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Huang X, Xu H. Regulating Excess Electrons in Reducible Metal Oxides for Enhanced Oxygen Evolution Reaction Activity: A Mini-Review. Chemphyschem 2024; 25:e202400081. [PMID: 38303551 DOI: 10.1002/cphc.202400081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Accepted: 01/31/2024] [Indexed: 02/03/2024]
Abstract
Identifying a universal activity descriptor for metal oxides, akin to the d-band center for transition metals, remains a significant challenge in catalyst design, largely due to the intricate electronic structures of metal oxides. This review highlights a major advancement in formulating the number of excess electrons (NEE) as an activity descriptor for oxygen evolution reaction (OER) on reducible metal oxide surfaces. We elaborate on the quantitative relationship between NEE and the adsorption properties of OER intermediates, and unveil the decisive role of the octet rule on the OER performance of these oxides. This insight provides a robust theoretical basis for designing effective OER catalysts. Moreover, we discuss critical experimental evidence supporting this theory and summarize recent advances in employing NEE as a guiding principle for developing highly efficient OER catalysts experimentally.
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Affiliation(s)
- Xiang Huang
- Department of Physics, Southern University of Science and Technology, Shenzhen, 518055, China
- Quantum Science Center of Guangdong-Hong Kong-Macao Greater Bay Area, Guangdong, Shenzhen, 518045, China
| | - Hu Xu
- Department of Physics, Southern University of Science and Technology, Shenzhen, 518055, China
- Quantum Science Center of Guangdong-Hong Kong-Macao Greater Bay Area, Guangdong, Shenzhen, 518045, China
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2
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Ma X, Shi Y, Cheng Z, Liu X, Liu J, Guo Z, Cui X, Sun X, Zhao J, Tan S, Wang B. Unveiling diverse coordination-defined electronic structures of reconstructed anatase TiO 2(001)-(1 × 4) surface. Nat Commun 2024; 15:2326. [PMID: 38485720 PMCID: PMC10940315 DOI: 10.1038/s41467-024-46570-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Accepted: 02/27/2024] [Indexed: 03/18/2024] Open
Abstract
Transition metal oxides (TMOs) exhibit fascinating physicochemical properties, which originate from the diverse coordination structures between the transition metal and oxygen atoms. Accurate determination of such structure-property relationships of TMOs requires to correlate structural and electronic properties by capturing the global parameters with high resolution in energy, real, and momentum spaces, but it is still challenging. Herein, we report the determination of characteristic electronic structures from diverse coordination environments on the prototypical anatase-TiO2(001) with (1 × 4) reconstruction, using high-resolution angle-resolved photoemission spectroscopy and scanning tunneling microscopy/atomic force microscopy, in combination with density functional theory calculation. We unveil that the shifted positions of O 2s and 2p levels and the gap-state Ti 3p levels can sensitively characterize the O and Ti coordination environments in the (1 × 4) reconstructed surface, which show distinguishable features from those in bulk. Our findings provide a paradigm to interrogate the intricate reconstruction-relevant properties in many other TMO surfaces.
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Affiliation(s)
- Xiaochuan Ma
- Hefei National Research Center for Physical Sciences at the Microscale and New Cornerstone Science Laboratory, University of Science and Technology of China, Hefei, Anhui, 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, Anhui, 230088, China
| | - Yongliang Shi
- Hefei National Research Center for Physical Sciences at the Microscale and New Cornerstone Science Laboratory, University of Science and Technology of China, Hefei, Anhui, 230026, China
| | - Zhengwang Cheng
- School of Science and Hubei Engineering Technology Research Center of Energy Photoelectric Device and System, Hubei University of Technology, Wuhan, Hubei, 430068, China
| | - Xiaofeng Liu
- School of Physics, Hefei University of Technology, Hefei, Auhui, 230009, China
| | - Jianyi Liu
- Hefei National Research Center for Physical Sciences at the Microscale and New Cornerstone Science Laboratory, University of Science and Technology of China, Hefei, Anhui, 230026, China
| | - Ziyang Guo
- Hefei National Research Center for Physical Sciences at the Microscale and New Cornerstone Science Laboratory, University of Science and Technology of China, Hefei, Anhui, 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, Anhui, 230088, China
| | - Xuefeng Cui
- Hefei National Research Center for Physical Sciences at the Microscale and New Cornerstone Science Laboratory, University of Science and Technology of China, Hefei, Anhui, 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, Anhui, 230088, China
| | - Xia Sun
- Hefei National Research Center for Physical Sciences at the Microscale and New Cornerstone Science Laboratory, University of Science and Technology of China, Hefei, Anhui, 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, Anhui, 230088, China
| | - Jin Zhao
- Hefei National Research Center for Physical Sciences at the Microscale and New Cornerstone Science Laboratory, University of Science and Technology of China, Hefei, Anhui, 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, Anhui, 230088, China
| | - Shijing Tan
- Hefei National Research Center for Physical Sciences at the Microscale and New Cornerstone Science Laboratory, University of Science and Technology of China, Hefei, Anhui, 230026, China.
- Hefei National Laboratory, University of Science and Technology of China, Hefei, Anhui, 230088, China.
| | - Bing Wang
- Hefei National Research Center for Physical Sciences at the Microscale and New Cornerstone Science Laboratory, University of Science and Technology of China, Hefei, Anhui, 230026, China.
- Hefei National Laboratory, University of Science and Technology of China, Hefei, Anhui, 230088, China.
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3
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He CY, Li Y, Zhou ZH, Liu BH, Gao XH. High-Entropy Photothermal Materials. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024:e2400920. [PMID: 38437805 DOI: 10.1002/adma.202400920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Revised: 02/28/2024] [Indexed: 03/06/2024]
Abstract
High-entropy (HE) materials, celebrated for their extraordinary chemical and physical properties, have garnered increasing attention for their broad applications across diverse disciplines. The expansive compositional range of these materials allows for nuanced tuning of their properties and innovative structural designs. Recent advances have been centered on their versatile photothermal conversion capabilities, effective across the full solar spectrum (300-2500 nm). The HE effect, coupled with hysteresis diffusion, imparts these materials with desirable thermal and chemical stability. These attributes position HE materials as a revolutionary alternative to traditional photothermal materials, signifying a transformative shift in photothermal technology. This review delivers a comprehensive summary of the current state of knowledge regarding HE photothermal materials, emphasizing the intricate relationship between their compositions, structures, light-absorbing mechanisms, and optical properties. Furthermore, the review outlines the notable advances in HE photothermal materials, emphasizing their contributions to areas, such as solar water evaporation, personal thermal management, solar thermoelectric generation, catalysis, and biomedical applications. The review culminates in presenting a roadmap that outlines prospective directions for future research in this burgeoning field, and also outlines fruitful ways to develop advanced HE photothermal materials and to expand their promising applications.
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Affiliation(s)
- Cheng-Yu He
- Laboratory of Clean Energy Chemistry and Materials, State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yang Li
- State Key Laboratory of Fluid Power and Mechatronic Systems, School of Mechanical Engineering, Zhejiang University, Hangzhou, 310027, China
- Key Laboratory of Advanced Manufacturing Technology of Zhejiang Province, School of Mechanical Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Zhuo-Hao Zhou
- Laboratory of Clean Energy Chemistry and Materials, State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000, China
| | - Bao-Hua Liu
- Laboratory of Clean Energy Chemistry and Materials, State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000, China
| | - Xiang-Hu Gao
- Laboratory of Clean Energy Chemistry and Materials, State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
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4
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Li J, Wang T, Xia S, Chen W, Ren Z, Sun M, Che L, Yang X, Zhou C. Site-Selective Excitation of Ti 3+ Ions in Rutile TiO 2 via Anisotropic Intra-Atomic 3d → 3d Transition. JACS AU 2024; 4:491-501. [PMID: 38425939 PMCID: PMC10900497 DOI: 10.1021/jacsau.3c00600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Revised: 12/06/2023] [Accepted: 01/03/2024] [Indexed: 03/02/2024]
Abstract
Site-selective excitation (SSE), which is usually realized by tuning the wavelength of absorbed light, is an ideal way to study bond-selective chemistry, analyze the crystal structure, investigate protein conformation, etc., eventually leading to active manipulation of desired processes. Herein, SSE has been explored in (110)-, (100)-, and (011)-faced rutile TiO2, a prototypical material in both surface science and photocatalysis fields. Using ultraviolet photoelectron spectroscopy and photon energy-, substrate orientation-, and laser polarization-dependent two-photon photoemission spectroscopy (2PPE), intra-atomic 3d → 3d transition from the split Ti3+ 3d orbitals, i.e., band gap states and excited states at ∼1.00 eV below and ∼2.40 eV above the Fermi level, respectively, has been proven for all of the samples, suggesting that it is a common property of this material. The distinct structure of rutile TiO2 results in the anisotropic 3d → 3d transitions with the transition dipole moment along the long axes ([110] and [11̅0]) of TiO6 blocking units. This anisotropy facilitates the selective excitation of Ti3+ ions in the two types of TiO6, which cannot be realized by conventional wavelength tuning, via polarization alignment of the excitation source. Discovery in this work builds the foundation for future investigation of site-selective photophysical and photochemical processes and eventually possible active manipulation in this material at the atomic level.
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Affiliation(s)
- Jialong Li
- Department
of Physics, School of Science, Dalian Maritime
University, 116026 Dalian, China
- State
Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 116023 Dalian, China
| | - Tianjun Wang
- State
Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 116023 Dalian, China
| | - Shucai Xia
- State
Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 116023 Dalian, China
| | - Wei Chen
- State
Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 116023 Dalian, China
- University
of Chinese Academy of Sciences, No.19A Yuquan Road, Shijingshan District, 100049 Beijing, China
| | - Zefeng Ren
- State
Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 116023 Dalian, China
| | - Min Sun
- Department
of Physics, School of Science, Dalian Maritime
University, 116026 Dalian, China
| | - Li Che
- Department
of Physics, School of Science, Dalian Maritime
University, 116026 Dalian, China
| | - Xueming Yang
- State
Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 116023 Dalian, China
- Department
of Chemistry, Southern University of Science
and Technology, 1088
Xueyuan Road, 518055 Shenzhen, Guangdong, China
| | - Chuanyao Zhou
- State
Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 116023 Dalian, China
- University
of Chinese Academy of Sciences, No.19A Yuquan Road, Shijingshan District, 100049 Beijing, China
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5
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Wang Z, Labat F. Modeling stoichiometric and oxygen defective TiO 2 anatase bulk and (101) surface: structural and electronic properties from hybrid DFT. J Mol Model 2023; 29:174. [PMID: 37166566 DOI: 10.1007/s00894-023-05584-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 05/05/2023] [Indexed: 05/12/2023]
Abstract
CONTEXT We present a periodic hybrid DFT investigation of the structural and electronic properties of both stoichiometric and oxygen-defective TiO2 anatase bulk and (101) surface, in singlet and triplet spin states. In all cases, an excellent agreement with available photoelectron spectroscopy data has been obtained, reproducing the offsets of the deep defect levels positions from the conduction band minimum of TiO2 created upon oxygen vacancy (VO) formation. For the bulk, different local structural polaronic distortions around the VO site have been evidenced depending on the spin state considered. Although a similar conclusion has been drawn for the defective surface for the nine different vacancy positions which have been considered, large migration of the twofold coordinated surface O atom has also been evidenced, up to the initial vacancy site in some cases. The very good agreement obtained with available experimental data regarding the offsets from the conduction band minimum of the deep defect levels positions both for the bulk and the (101) surface of TiO2 anatase is encouraging for the application of the proposed hybrid-based computational strategy to TiO2 surface-related processes such as TiO2-based photocatalysis in which oxygen vacancies are known to play a key role. METHODS All calculations have been performed with Crystal17, considering different hybrid functionals with both effective core pseudopotentials and all-electron atom-centered basis sets, as well as additional empirical dispersion effects with the D2 and D3 models.
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Affiliation(s)
- Zihan Wang
- Chimie ParisTech, PSL University, CNRS UMR 8060, Institute of Chemistry for Life and Health Sciences, Theoretical Chemistry and Modeling Group, F-75005, Paris, France
| | - Frédéric Labat
- Chimie ParisTech, PSL University, CNRS UMR 8060, Institute of Chemistry for Life and Health Sciences, Theoretical Chemistry and Modeling Group, F-75005, Paris, France.
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6
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Apergi S, Koch C, Brocks G, Olthof S, Tao S. Decomposition of Organic Perovskite Precursors on MoO 3: Role of Halogen and Surface Defects. ACS APPLIED MATERIALS & INTERFACES 2022; 14:34208-34219. [PMID: 35107986 PMCID: PMC9353771 DOI: 10.1021/acsami.1c20847] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Despite the rapid progress in perovskite solar cells, their commercialization is still hindered by issues regarding long-term stability, which can be strongly affected by metal oxide-based charge extraction layers next to the perovskite material. With MoO3 being one of the most successful hole transport layers in organic photovoltaics, the disastrous results of its combination with perovskite films came as a surprise but was soon attributed to severe chemical instability at the MoO3/perovskite interface. To discover the atomistic origin of this instability, we combine density functional theory (DFT) calculations and X-ray photoelectron spectroscopy (XPS) measurements to investigate the interaction of MoO3 with the perovskite precursors MAI, MABr, FAI, and FABr. From DFT calculations we suggest a scenario that is based upon oxygen vacancies playing a key role in interface degradation reactions. Not only do these vacancies promote decomposition reactions of perovskite precursors, but they also constitute the reaction centers for redox reactions leading to oxidation of the halides and reduction of Mo. Specifically iodides are proposed to be reactive, while bromides do not significantly affect the oxide. XPS measurements reveal a severe reduction of Mo and a loss of the halide species when the oxide is interfaced with I-containing precursors, which is consistent with the proposed scenario. In line with the latter, experimentally observed effects are much less pronounced in case of Br-containing precursors. We further find that the reactivity of the MoO3 substrate can be moderated by reducing the number of oxygen vacancies through a UV/ozone treatment, though it cannot be fully eliminated.
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Affiliation(s)
- Sofia Apergi
- Materials
Simulation and Modelling, Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
- Center
for Computational Energy Research, Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - Christine Koch
- Department
of Chemistry, University of Cologne, Greinstraße 4-6, 50939 Cologne, Germany
| | - Geert Brocks
- Materials
Simulation and Modelling, Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
- Center
for Computational Energy Research, Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
- Computational
Materials Science, Faculty of Science and Technology and MESA+, Institute
for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Selina Olthof
- Department
of Chemistry, University of Cologne, Greinstraße 4-6, 50939 Cologne, Germany
| | - Shuxia Tao
- Materials
Simulation and Modelling, Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
- Center
for Computational Energy Research, Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
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7
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Ma X, Shi Y, Liu J, Li X, Cui X, Tan S, Zhao J, Wang B. Hydrogen-Bond Network Promotes Water Splitting on the TiO 2 Surface. J Am Chem Soc 2022; 144:13565-13573. [DOI: 10.1021/jacs.2c03690] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Xiaochuan Ma
- Hefei National Research Center for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Yongliang Shi
- Center for Spintronics and Quantum Systems, State Key Laboratory for Mechanical Behavior of Materials, School of Materials Science and Engineering, Xi’an Jiaotong University, Xi’an, Shaanxi 710049, China
| | - Jianyi Liu
- Hefei National Research Center for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Xintong Li
- Hefei National Research Center for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Xuefeng Cui
- Hefei National Research Center for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, China
| | - Shijing Tan
- Hefei National Research Center for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, China
| | - Jin Zhao
- Hefei National Research Center for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- ICQD/Hefei National Research Center for Physical Sciences at the Microscale, and CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics, and Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Bing Wang
- Hefei National Research Center for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, China
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8
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Pacchioni G, Rahman TS. Defect engineering of oxide surfaces: dream or reality? JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:291501. [PMID: 35504272 DOI: 10.1088/1361-648x/ac6c6d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 05/03/2022] [Indexed: 06/14/2023]
Abstract
In this brief perspective we analyze the present status of the field of defect engineering of oxide surfaces. In particular we discuss the tools and techniques available to generate, identify, quantify, and characterize point defects at oxide surfaces and the main areas where these centers play a role in practical applications.
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Affiliation(s)
- Gianfranco Pacchioni
- Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, via R. Cozzi 55, 202125, Milano, Italy
| | - Talat S Rahman
- Department of Physics, University of Central Florida, Orlando, FL 32816, United States of America
- Renewable Energy and Chemical Transformation Cluster, University of Central Florida, Orlando, FL 32816, United States of America
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9
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Shi BX, Kapil V, Zen A, Chen J, Alavi A, Michaelides A. General embedded cluster protocol for accurate modeling of oxygen vacancies in metal-oxides. J Chem Phys 2022; 156:124704. [DOI: 10.1063/5.0087031] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The O vacancy (Ov) formation energy, EOv, is an important property of a metal-oxide, governing its performance in applications such as fuel cells or heterogeneous catalysis. These defects are routinely studied with density functional theory (DFT). However, it is well-recognized that standard DFT formulations (e.g., the generalized gradient approximation) are insufficient for modeling the Ov, requiring higher levels of theory. The embedded cluster method offers a promising approach to compute EOv accurately, giving access to all electronic structure methods. Central to this approach is the construction of quantum(-mechanically treated) clusters placed within suitable embedding environments. Unfortunately, current approaches to constructing the quantum clusters either require large system sizes, preventing application of high-level methods, or require significant manual input, preventing investigations of multiple systems simultaneously. In this work, we present a systematic and general quantum cluster design protocol that can determine small converged quantum clusters for studying the Ov in metal-oxides with accurate methods, such as local coupled cluster with single, double, and perturbative triple excitations. We apply this protocol to study the Ov in the bulk and surface planes of rutile TiO2 and rock salt MgO, producing the first accurate and well-converged determinations of EOv with this method. These reference values are used to benchmark exchange–correlation functionals in DFT, and we find that all the studied functionals underestimate EOv, with the average error decreasing along the rungs of Jacob’s ladder. This protocol is automatable for high-throughput calculations and can be generalized to study other point defects or adsorbates.
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Affiliation(s)
- Benjamin X. Shi
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Venkat Kapil
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
- Churchill College, University of Cambridge, Storey’s Way, Cambridge CB3 0DS, United Kingdom
| | - Andrea Zen
- Dipartimento di Fisica Ettore Pancini, Università di Napoli Federico II, Monte S. Angelo, I-80126 Napoli, Italy
- Department of Earth Sciences, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Ji Chen
- School of Physics, Peking University, Beijing 100871, China
| | - Ali Alavi
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Angelos Michaelides
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
- Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom
- Thomas Young Centre and London Centre for Nanotechnology, 17-19 Gordon Street, London WC1H 0AH, United Kingdom
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10
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Tanner AJ, Thornton G. TiO 2 Polarons in the Time Domain: Implications for Photocatalysis. J Phys Chem Lett 2022; 13:559-566. [PMID: 35014263 PMCID: PMC9097515 DOI: 10.1021/acs.jpclett.1c03677] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 01/03/2022] [Indexed: 06/14/2023]
Abstract
Exploiting the availability of solar energy to produce valuable chemicals is imperative in our quest for a sustainable energy cycle. TiO2 has emerged as an efficient photocatalyst, and as such its photochemistry has been studied extensively. It is well-known that polaronic defect states impact the activity of this chemistry. As such, understanding the fundamental excitation mechanisms deserves the attention of the scientific community. However, isolating the contribution of polarons to these processes has required increasingly creative experimental techniques and expensive theory. In this Perspective, we discuss recent advances in this field, with a particular focus on two-photon photoemission spectroscopy (2PPE) and density functional theory (DFT), and discuss the implications for photocatalysis.
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11
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Wang T, Chen W, Xia S, Ren Z, Dai D, Yang X, Zhou C. Anisotropic d-d Transition in Rutile TiO 2. J Phys Chem Lett 2021; 12:10515-10520. [PMID: 34677987 DOI: 10.1021/acs.jpclett.1c02931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The band gap state of TiO2, which is dominated by Ti3+ 3d character, is of great relevance to light absorption, electron trapping, charge recombination, and conduction band structure. Despite the importance, the explanation of the excitation from this state is controversial. To this end, the electronic structures of TiO2(110) and TiO2(011)-(2 × 1) have been systematically measured with two-photon photoemission spectroscopy. The results reveal the anisotropic nature of the electronic structure in rutile TiO2 at seemingly equivalent directions of [110] and [11̅0], the long axes of the TiO6 blocking unit. Although the resonant energy of these two d-d transitions is identical, the energy levels are systematically shifted by 0.1 eV. We propose this anisotropy originates from the broken symmetry of the rutile TiO2 crystals caused by the surface. The proposed asymmetry-caused electronic structure anisotropy could be generalized to other similar materials and may affect associated catalytic properties. This work provides an important benchmark for related calculations.
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Affiliation(s)
- Tianjun Wang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Science, 457 Zhongshan Road, Dalian 116023, Liaoning, P.R. China
| | - Wei Chen
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Science, 457 Zhongshan Road, Dalian 116023, Liaoning, P.R. China
- University of Chinese Academy of Sciences, No. 19A Yuquan Road, Shijingshan District, 100049 Beijing, P.R. China
| | - Shucai Xia
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Science, 457 Zhongshan Road, Dalian 116023, Liaoning, P.R. China
- University of Chinese Academy of Sciences, No. 19A Yuquan Road, Shijingshan District, 100049 Beijing, P.R. China
| | - Zefeng Ren
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Science, 457 Zhongshan Road, Dalian 116023, Liaoning, P.R. China
| | - Dongxu Dai
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Science, 457 Zhongshan Road, Dalian 116023, Liaoning, P.R. China
| | - Xueming Yang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Science, 457 Zhongshan Road, Dalian 116023, Liaoning, P.R. China
- Department of Chemistry, Southern University of Science and Technology, 1088 Xueyuan Road, Shenzhen, Guangdong 518055, P.R. China
| | - Chuanyao Zhou
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Science, 457 Zhongshan Road, Dalian 116023, Liaoning, P.R. China
- University of Chinese Academy of Sciences, No. 19A Yuquan Road, Shijingshan District, 100049 Beijing, P.R. China
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12
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Zeng J, Li Z, Jiang H, Wang X. Progress on photocatalytic semiconductor hybrids for bacterial inactivation. MATERIALS HORIZONS 2021; 8:2964-3008. [PMID: 34609391 DOI: 10.1039/d1mh00773d] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Due to its use of green and renewable energy and negligible bacterial resistance, photocatalytic bacterial inactivation is to be considered a promising sterilization process. Herein, we explore the relevant mechanisms of the photoinduced process on the active sites of semiconductors with an emphasis on the active sites of semiconductors, the photoexcited electron transfer, ROS-induced toxicity and interactions between semiconductors and bacteria. Pristine semiconductors such as metal oxides (TiO2 and ZnO) have been widely reported; however, they suffer some drawbacks such as narrow optical response and high photogenerated carrier recombination. Herein, some typical modification strategies will be discussed including noble metal doping, ion doping, hybrid heterojunctions and dye sensitization. Besides, the biosafety and biocompatibility issues of semiconductor materials are also considered for the evaluation of their potential for further biomedical applications. Furthermore, 2D materials have become promising candidates in recent years due to their wide optical response to NIR light, superior antibacterial activity and favorable biocompatibility. Besides, the current research limitations and challenges are illustrated to introduce the appealing directions and design considerations for the future development of photocatalytic semiconductors for antibacterial applications.
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Affiliation(s)
- Jiayu Zeng
- State Key Laboratory of Bioelectronics (Chien-Shiung Wu Lab), School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China.
| | - Ziming Li
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Hui Jiang
- State Key Laboratory of Bioelectronics (Chien-Shiung Wu Lab), School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China.
| | - Xuemei Wang
- State Key Laboratory of Bioelectronics (Chien-Shiung Wu Lab), School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China.
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13
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Etim UJ, Bai P, Gazit OM, Zhong Z. Low-Temperature Heterogeneous Oxidation Catalysis and Molecular Oxygen Activation. CATALYSIS REVIEWS 2021. [DOI: 10.1080/01614940.2021.1919044] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Ubong J. Etim
- Department of Chemical Engineering, Guangdong Technion-Israel Institute of Technology (GTIIT), Shantou, Guangdong, China
| | - Peng Bai
- College of Chemical Engineering, China University of Petroleum, Qingdao, China
| | - Oz M. Gazit
- Wolfson Faculty of Chemical Engineering, Technion – Israel Institute of Technology, Haifa, Israel
| | - Ziyi Zhong
- Department of Chemical Engineering, Guangdong Technion-Israel Institute of Technology (GTIIT), Shantou, Guangdong, China
- Technion Israel Institute of Technology (IIT), Haifa, Israel
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14
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Zhang H, Zhang Z, Liu Y, Fang X, Xu J, Wang X, Xu X. Band-Gap Engineering: A New Tool for Tailoring the Activity of Semiconducting Oxide Catalysts for CO Oxidation. J Phys Chem Lett 2021; 12:9188-9196. [PMID: 34528804 DOI: 10.1021/acs.jpclett.1c02471] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Cation or anion vacancies in semiconducting oxides usually benefit activity for CO oxidation. To study the nature of vacancy engineering for a thermocatalytic reaction, we adopted lattice doping of cations with varied valence states to construct anion and cation vacancies in n-type and p-type semiconducting CeO2 and NiO, respectively. Doping cations can effectively regulate the number of the vacancies, thus tailoring the activity for CO oxidation. The strong correlation of activation energy and specific activity with a catalyst band gap verified that the nature of vacancy engineering for activity of CeO2 and NiO for CO oxidation can be attributed to tailoring of the band gap. The larger the vacancy amount, the smaller the band gap, and the lower the activation energy, thus giving a higher specific activity. Band-gap engineering, widely used for photocatalytic processes, can be a new tool for tailoring the activity of semiconducting oxide catalysts for thermocatalytic reactions.
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Affiliation(s)
- Hongmin Zhang
- Key Laboratory of Jiangxi Province for Environment and Energy Catalysis, College of Chemistry, Nanchang University, Nanchang, Jiangxi 330031, China
| | - Zhiqiang Zhang
- Key Laboratory of Jiangxi Province for Environment and Energy Catalysis, College of Chemistry, Nanchang University, Nanchang, Jiangxi 330031, China
| | - Yameng Liu
- Key Laboratory of Jiangxi Province for Environment and Energy Catalysis, College of Chemistry, Nanchang University, Nanchang, Jiangxi 330031, China
| | - Xiuzhong Fang
- Key Laboratory of Jiangxi Province for Environment and Energy Catalysis, College of Chemistry, Nanchang University, Nanchang, Jiangxi 330031, China
| | - Junwei Xu
- Key Laboratory of Jiangxi Province for Environment and Energy Catalysis, College of Chemistry, Nanchang University, Nanchang, Jiangxi 330031, China
| | - Xiang Wang
- Key Laboratory of Jiangxi Province for Environment and Energy Catalysis, College of Chemistry, Nanchang University, Nanchang, Jiangxi 330031, China
| | - Xianglan Xu
- Key Laboratory of Jiangxi Province for Environment and Energy Catalysis, College of Chemistry, Nanchang University, Nanchang, Jiangxi 330031, China
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15
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Yim CM, Lamoureux PS, Mellor A, Pang CL, Idriss H, Pacchioni G, Thornton G. Size and Shape Dependence of the Electronic Structure of Gold Nanoclusters on TiO 2. J Phys Chem Lett 2021; 12:8363-8369. [PMID: 34432476 DOI: 10.1021/acs.jpclett.1c02167] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Understanding the mechanism behind the superior catalytic power of single- or few-atom heterogeneous catalysts has become an important topic in surface chemistry. This is particularly the case for gold, with TiO2 being an efficient support. Here we use scanning tunneling microscopy/spectroscopy with theoretical calculations to investigate the adsorption geometry and local electronic structure of several-atom Au clusters on rutile TiO2(110), with the clusters fabricated by controlled manipulation of single atoms. Our study confirms that Au1 and Au2 clusters prefer adsorption at surface O vacancies. Au3 clusters adsorb at O vacancies in a linear-chain configuration parallel to the surface; in the absence of O vacancies they adsorb at Ti5c sites with a structure of a vertically pointing upright triangle. We find that both the electronic structure and cluster-substrate charge transfer depend critically on the cluster size, bonding configuration, and local environment. This suggests the possibility of engineering cluster selectivity for specific catalytic reactions.
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Affiliation(s)
- Chi-Ming Yim
- Department of Chemistry and London Centre for Nanotechnology, University College London, 20 Gordon Street, London WC1H 0AJ, U.K
| | - Philomena Schlexer Lamoureux
- Dipartimento di Scienza dei Materiali, Università degli Studi Milano-Bicocca, via R. Cozzi 55, 20126 Milano, Italy
| | - Andrew Mellor
- Department of Chemistry and London Centre for Nanotechnology, University College London, 20 Gordon Street, London WC1H 0AJ, U.K
| | - Chi L Pang
- Department of Chemistry and London Centre for Nanotechnology, University College London, 20 Gordon Street, London WC1H 0AJ, U.K
| | - Hicham Idriss
- Surface Science and Advanced Characterisation, Chemical Sciences Division, SABIC-CRD at KAUST, Thuwal 23955, Saudi Arabia
| | - Gianfranco Pacchioni
- Dipartimento di Scienza dei Materiali, Università degli Studi Milano-Bicocca, via R. Cozzi 55, 20126 Milano, Italy
| | - Geoff Thornton
- Department of Chemistry and London Centre for Nanotechnology, University College London, 20 Gordon Street, London WC1H 0AJ, U.K
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16
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Tanner AJ, Kerr R, Fielding HH, Thornton G. Chemical Modification of Polaronic States in Anatase TiO 2(101). THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2021; 125:14348-14355. [PMID: 34267854 PMCID: PMC8273885 DOI: 10.1021/acs.jpcc.1c03684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Revised: 06/02/2021] [Indexed: 06/13/2023]
Abstract
Two polymorphs of TiO2, anatase and rutile, are employed in photocatalytic applications. It is broadly accepted that anatase is the more catalytically active and subsequently finds wider commercial use. In this work, we focus on the Ti3+ polaronic states of anatase TiO2(101), which lie at ∼1.0 eV binding energy and are known to increase catalytic performance. Using UV-photoemission and two-photon photoemission spectroscopies, we demonstrate the capability to tune the excited state resonance of polarons by controlling the chemical environment. Anatase TiO2(101) contains subsurface polarons which undergo sub-band-gap photoexcitation to states ∼2.0 eV above the Fermi level. Formic acid adsorption dramatically influences the polaronic states, increasing the binding energy by ∼0.3 eV. Moreover, the photoexcitation oscillator strength changes significantly, resonating with states ∼3.0 eV above the Fermi level. We show that this behavior is likely due to the surface migration of subsurface oxygen vacancies.
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Affiliation(s)
- Alex J. Tanner
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
- London
Centre for Nanotechnology, University College
London, 17-19 Gordon Street, London WC1H 0AH, United Kingdom
| | - Robin Kerr
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
- London
Centre for Nanotechnology, University College
London, 17-19 Gordon Street, London WC1H 0AH, United Kingdom
| | - Helen H. Fielding
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | - Geoff Thornton
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
- London
Centre for Nanotechnology, University College
London, 17-19 Gordon Street, London WC1H 0AH, United Kingdom
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17
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Tanner AJ, Wen B, Ontaneda J, Zhang Y, Grau-Crespo R, Fielding HH, Selloni A, Thornton G. Polaron-Adsorbate Coupling at the TiO 2(110)-Carboxylate Interface. J Phys Chem Lett 2021; 12:3571-3576. [PMID: 33819053 PMCID: PMC8054240 DOI: 10.1021/acs.jpclett.1c00678] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 03/31/2021] [Indexed: 06/12/2023]
Abstract
Understanding how adsorbates influence polaron behavior is of fundamental importance in describing the catalytic properties of TiO2. Carboxylic acids adsorb readily at TiO2 surfaces, yet their influence on polaronic states is unknown. Using UV photoemission spectroscopy (UPS), two-photon photoemission spectroscopy (2PPE), and density functional theory (DFT) we show that dissociative adsorption of formic and acetic acids has profound, yet different, effects on the surface density, crystal field, and photoexcitation of polarons in rutile TiO2(110). We also show that these variations are governed by the contrasting electrostatic properties of the acids, which impacts the extent of polaron-adsorbate coupling. The density of polarons in the surface region increases more in formate-terminated TiO2(110) relative to acetate. Consequently, increased coupling gives rise to new photoexcitation channels via states 3.83 eV above the Fermi level. The onset of this process is 3.45 eV, likely adding to the catalytic photoyield.
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Affiliation(s)
- Alex J. Tanner
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
- London
Centre for Nanotechnology, University College
London, 17-19 Gordon
Street, London WC1H 0AH, United Kingdom
| | - Bo Wen
- Department
of Chemistry, Princeton University, Princeton, New Jersey 08540, United States
| | - Jorge Ontaneda
- Department
of Chemistry, University of Reading, Whiteknights, Reading RG6 6AX, United Kingdom
| | - Yu Zhang
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
- London
Centre for Nanotechnology, University College
London, 17-19 Gordon
Street, London WC1H 0AH, United Kingdom
| | - Ricardo Grau-Crespo
- Department
of Chemistry, University of Reading, Whiteknights, Reading RG6 6AX, United Kingdom
| | - Helen H. Fielding
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | - Annabella Selloni
- Department
of Chemistry, Princeton University, Princeton, New Jersey 08540, United States
| | - Geoff Thornton
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
- London
Centre for Nanotechnology, University College
London, 17-19 Gordon
Street, London WC1H 0AH, United Kingdom
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18
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Chen J, Bogdanov NA, Usvyat D, Fang W, Michaelides A, Alavi A. The color center singlet state of oxygen vacancies in TiO2. J Chem Phys 2020; 153:204704. [DOI: 10.1063/5.0030658] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Affiliation(s)
- Ji Chen
- School of Physics, Peking University, Beijing 100871, People’s Republic of China
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-St. 2, D-12489 Berlin, Germany
| | - Nikolay A. Bogdanov
- Max Planck Institute for Solid State Research, Heisenbergstrasse 1, 70569 Stuttgart, Germany
| | - Denis Usvyat
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-St. 2, D-12489 Berlin, Germany
| | - Wei Fang
- Laboratory of Physical Chemistry, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Angelos Michaelides
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-St. 2, D-12489 Berlin, Germany
- Department of Physics and Astronomy, London Centre for Nanotechnology, Thomas Young Centre, University College London, Gower Street, London WC1E 6BT, United Kingdom
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Ali Alavi
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-St. 2, D-12489 Berlin, Germany
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
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19
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Guo C, Meng X, Fu H, Wang Q, Wang H, Tian Y, Peng J, Ma R, Weng Y, Meng S, Wang E, Jiang Y. Probing Nonequilibrium Dynamics of Photoexcited Polarons on a Metal-Oxide Surface with Atomic Precision. PHYSICAL REVIEW LETTERS 2020; 124:206801. [PMID: 32501065 DOI: 10.1103/physrevlett.124.206801] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2019] [Revised: 01/26/2020] [Accepted: 04/09/2020] [Indexed: 06/11/2023]
Abstract
Understanding the nonequilibrium dynamics of photoexcited polarons at the atomic scale is of great importance for improving the performance of photocatalytic and solar-energy materials. Using a pulsed-laser-combined scanning tunneling microscopy and spectroscopy, here we succeeded in resolving the relaxation dynamics of single polarons bound to oxygen vacancies on the surface of a prototypical photocatalyst, rutile TiO_{2}(110). The visible-light excitation of the defect-derived polarons depletes the polaron states and leads to delocalized free electrons in the conduction band, which is further corroborated by ab initio calculations. We found that the trapping time of polarons becomes considerably shorter when the polaron is bound to two surface oxygen vacancies than that to one. In contrast, the lifetime of photogenerated free electrons is insensitive to the atomic-scale distribution of the defects but correlated with the averaged defect density within a nanometer-sized area. Those results shed new light on the photocatalytically active sites at the metal-oxide surface.
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Affiliation(s)
- Chaoyu Guo
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, People's Republic of China
- Physical Science Laboratory, Huairou National Comprehensive Science Centre, Beijing 101400, People's Republic of China
| | - Xiangzhi Meng
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, People's Republic of China
| | - Huixia Fu
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Qin Wang
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, People's Republic of China
| | - Huimin Wang
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Ye Tian
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, People's Republic of China
| | - Jinbo Peng
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, People's Republic of China
| | - Runze Ma
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, People's Republic of China
| | - Yuxiang Weng
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Sheng Meng
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- Collaborative Innovation Center of Quantum Matter, Beijing 100871, People's Republic of China
| | - Enge Wang
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, People's Republic of China
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- Collaborative Innovation Center of Quantum Matter, Beijing 100871, People's Republic of China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Ying Jiang
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, People's Republic of China
- Collaborative Innovation Center of Quantum Matter, Beijing 100871, People's Republic of China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, People's Republic of China
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20
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Di Liberto G, Tosoni S, Illas F, Pacchioni G. Nature of SrTiO3/TiO2 (anatase) heterostructure from hybrid density functional theory calculations. J Chem Phys 2020; 152:184704. [DOI: 10.1063/5.0007138] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Affiliation(s)
- Giovanni Di Liberto
- Dipartimento di Scienza dei Materiali, Università di Milano Bicocca, via Roberto Cozzi 55, 20125 Milano, Italy
| | - Sergio Tosoni
- Dipartimento di Scienza dei Materiali, Università di Milano Bicocca, via Roberto Cozzi 55, 20125 Milano, Italy
| | - Francesc Illas
- Departament de Ciència de Materials i Química Física and Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona, c/Martí i Franquès 1-11, 08028 Barcelona, Spain
| | - Gianfranco Pacchioni
- Dipartimento di Scienza dei Materiali, Università di Milano Bicocca, via Roberto Cozzi 55, 20125 Milano, Italy
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21
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Kick M, Grosu C, Schuderer M, Scheurer C, Oberhofer H. Mobile Small Polarons Qualitatively Explain Conductivity in Lithium Titanium Oxide Battery Electrodes. J Phys Chem Lett 2020; 11:2535-2540. [PMID: 32162917 DOI: 10.1021/acs.jpclett.0c00568] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Lithium titanium oxide Li4Ti5O12 is an intriguing anode material promising particularly long-life batteries, due to its remarkable phase stability during (dis)charging of the cell. However, its usage is limited by its low intrinsic electronic conductivity. Introducing oxygen vacancies can be one method for overcoming this drawback, possibly by altering the charge carrier transport mechanism. We use Hubbard corrected density functional theory to show that polaronic states in combination with a possible hopping mechanism can play a crucial role in the experimentally observed increase in electronic conductivity. To gauge polaronic charge mobility, we compute the relative stabilities of different localization patterns and estimate polaron hopping barrier heights.
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Affiliation(s)
- Matthias Kick
- Chair for Theoretical Chemistry and Catalysis Research Center, Technical University of Munich, Lichtenbergstrasse 4, 85747 Garching, Germany
| | - Cristina Grosu
- Chair for Theoretical Chemistry and Catalysis Research Center, Technical University of Munich, Lichtenbergstrasse 4, 85747 Garching, Germany
- Institute of Energy and Climate Research (IEK-9), Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Markus Schuderer
- Chair for Theoretical Chemistry and Catalysis Research Center, Technical University of Munich, Lichtenbergstrasse 4, 85747 Garching, Germany
| | - Christoph Scheurer
- Chair for Theoretical Chemistry and Catalysis Research Center, Technical University of Munich, Lichtenbergstrasse 4, 85747 Garching, Germany
| | - Harald Oberhofer
- Chair for Theoretical Chemistry and Catalysis Research Center, Technical University of Munich, Lichtenbergstrasse 4, 85747 Garching, Germany
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22
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Nagatsuka N, Wilde M, Fukutani K. Hydrogenation and hydrogen diffusion at the anatase TiO2(101) surface. J Chem Phys 2020; 152:074708. [DOI: 10.1063/1.5142776] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Naoki Nagatsuka
- Institute of Industrial Science, The University of Tokyo, Komaba Meguro-ku, Tokyo 153-8505, Japan
| | - Markus Wilde
- Institute of Industrial Science, The University of Tokyo, Komaba Meguro-ku, Tokyo 153-8505, Japan
| | - Katsuyuki Fukutani
- Institute of Industrial Science, The University of Tokyo, Komaba Meguro-ku, Tokyo 153-8505, Japan
- Advanced Science Research Center, Japan Atomic Energy Agency (JAEA), Tokai, Ibaraki 319-1195, Japan
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23
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Mellor A, Wilson A, Pang CL, Yim CM, Maccherozzi F, Dhesi SS, Muryn CA, Idriss H, Thornton G. Photoemission core level binding energies from multiple sized nanoparticles on the same support: TiO 2(110)/Au. J Chem Phys 2020; 152:024709. [PMID: 31941300 DOI: 10.1063/1.5135760] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
A novel method of measuring the core level binding energies of multiple sized nanoparticles on the same substrate is demonstrated using the early stage of Au nanoparticle growth on reduced r-TiO2(110). This method employed in situ scanning tunneling microscopy (STM) and microfocused X-ray photoemission spectroscopy. An STM tip-shadowing method was used to synthesize patterned areas of Au nanoparticles on the substrate with different coverages and sizes. Patterns were identified and imaged using a UV photoelectron emission microscope. The Au 4f core level binding energies of the nanoparticles were investigated as a function of Au nanoparticle coverage and size. A combination of initial and final state effects modifies the binding energies of the Au 4f core levels as the nanoparticle size changes. When single Au atoms and Au3 clusters are present, the Au 4f7/2 binding energy, 84.42 eV, is similar to that observed at a high coverage (1.8 monolayer equivalent), resulting from a cancellation of initial and final state effects. As the coverage is increased, there is a decrease in binding energy, which then increases at a higher coverage to 84.39 eV. These results are consistent with a Volmer-Weber nucleation-growth model of Au nanoparticles at oxygen vacancies, resulting in electron transfer to the nanoparticles.
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Affiliation(s)
- Andrew Mellor
- Department of Chemistry and London Centre for Nanotechnology, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | - Axel Wilson
- Diamond Light Source, Harwell Science and Innovation Campus, Oxfordshire OX11 0DE, United Kingdom
| | - Chi L Pang
- Department of Chemistry and London Centre for Nanotechnology, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | - Chi M Yim
- Department of Chemistry and London Centre for Nanotechnology, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | - Francesco Maccherozzi
- Diamond Light Source, Harwell Science and Innovation Campus, Oxfordshire OX11 0DE, United Kingdom
| | - Sarnjeet S Dhesi
- Diamond Light Source, Harwell Science and Innovation Campus, Oxfordshire OX11 0DE, United Kingdom
| | - Christopher A Muryn
- School of Chemistry and Photon Science Institute, The University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Hicham Idriss
- Department of Chemistry and London Centre for Nanotechnology, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | - Geoff Thornton
- Department of Chemistry and London Centre for Nanotechnology, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
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24
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Jain N, Roy A, De A. Ba-addition induced enhanced surface reducibility of SrTiO 3: implications on catalytic aspects. NANOSCALE ADVANCES 2019; 1:4938-4946. [PMID: 36133134 PMCID: PMC9417473 DOI: 10.1039/c9na00540d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 10/28/2019] [Indexed: 06/16/2023]
Abstract
Surface reducibility engineering is one of the vital tools to enhance the catalytic activity of materials. A heavy redox treatment can be utilized to affect the structure and surface of catalytic materials. Here, we choose SrTiO3 (STO) with a cubic perovskite structure as a system to induce oxygen vacancies by using nascent hydrogen from NaBH4 leading to a heavily reduced version of SrTiO3 (RSTO). To further understand the surface reduction and its dependence on foreign-ion (Ba) incorporation into SrTiO3, Sr0.5Ba0.5TiO3 (SBTO) and BaTiO3 (BTO) are synthesized using a facile hydrothermal method. The reduced version of the pristine and mixed oxide shows distinct optical absorptions, indicating oxygen vacancy-mediated reducibility engineering. Detailed CO oxidation experiments suggest the order of activity over the as-prepared and reduced supports as STO > SBTO > BTO and RSBTO > RSTO > RBTO, respectively. The interesting observation of reversal of CO oxidation activity over STO and SBTO after reduction negates the assumption of a similar intensity of reduction on the surfaces of these oxide supports. The fundamental aspect of surface reducibility is addressed using temperature programmed reduction/oxidation (TPR/TPO) and XPS.
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Affiliation(s)
- Noopur Jain
- Department of Biological Sciences, National University of Singapore (NUS) Singapore
- Materials Research Centre, Indian Institute of Science (IISc) Bangalore-560012 India
| | - Ahin Roy
- Department of Biological Sciences, National University of Singapore (NUS) Singapore
| | - Angana De
- Department of Biological Sciences, National University of Singapore (NUS) Singapore
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25
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Walenta CA, Tschurl M, Heiz U. Introducing catalysis in photocatalysis: What can be understood from surface science studies of alcohol photoreforming on TiO 2. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:473002. [PMID: 31342942 DOI: 10.1088/1361-648x/ab351a] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Mechanisms in heterogeneous photocatalysis have traditionally been interpreted by the band-structure model and analogously to electrochemistry. This has led to the establishment of 'band-engineering' as a leading principle for the discovery of more efficient photocatalysts. In such a picture, mainly thermodynamic aspects are taken into account, while kinetics are often ignored. This holds in particular for chemical kinetics, which are, other than those for charge carrier dynamics, often not at all considered for the interpretation of the catalysts' photocatalytic performance. However, while being usually neglected in photocatalyis, they are a traditional and powerful tool in thermal catalysis and are still applied with great success in this field. While surface science studies made substantial contributes to thermal catalysis, analogous studies in heterogeneous photocatalysis still play only a minor role. In this review, the authors show that the photo-physics of defined materials in well-defined environments can be correlated with photochemical events on a surface, highlighting the importance of well-characterized semiconductors for the interpretation of mechanisms in heterogeneous photochemistry. The work focuses on contributions from surface science, which were obtained for the model system of a titania single crystal and alcohol photo-reforming. It is demonstrated that only surface science studies have so far enabled the elucidation of molecularly precise reaction mechanisms, the determination of reaction intermediates and assignment of reactive sites. As the identification of these properties remain major prerequisites for a breakthrough in photocatalysis research, the work also discusses the implications of the findings for applied systems. In general, the results from surface science demonstrate that photocatalytic systems shall also be approached by a perspective originating from heterogeneous catalysis rather than solely from an electrochemical point of view.
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Kick M, Oberhofer H. Towards a transferable design of solid-state embedding models on the example of a rutile TiO2 (110) surface. J Chem Phys 2019; 151:184114. [DOI: 10.1063/1.5125204] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- M. Kick
- Chair for Theoretical Chemistry and Catalysis Research Center, Technical University of Munich, Lichtenbergstr. 4, 85747 Garching, Germany
| | - H. Oberhofer
- Chair for Theoretical Chemistry and Catalysis Research Center, Technical University of Munich, Lichtenbergstr. 4, 85747 Garching, Germany
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27
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Dong S, Li B, Cui X, Tan S, Wang B. Photoresponses of Supported Au Single Atoms on TiO 2(110) through the Metal-Induced Gap States. J Phys Chem Lett 2019; 10:4683-4691. [PMID: 31364858 DOI: 10.1021/acs.jpclett.9b01527] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
When a metal single-atom (SA) catalyst is supported on a semiconducting photocatalyst, the charge transfer of the photoexcited carriers to metal SAs can provide a synergetic activity for the co-catalysts. Here, we report the interfacial electronic coupling of the Au SAs on the TiO2(110) surface using scanning tunneling microscopy/spectroscopy, in combination with first-principles calculations. Distinct energy and spatial distributions of the metal-induced gap states (MIGSs) are experimentally revealed for the Au SAs adsorbed at the terminal Ti sites and the oxygen vacancies. The localized MIGS below the Fermi level provides a dedicated channel for the transfer of a photoexcited hole from the TiO2 substrate to the adsorbed Au SAs. The hole can weaken the Ti-Au bonding and activate the diffusion of Au SAs. Our results shed light on combining the advantages of photocatalysis and metal SA catalysis using a co-catalyst, which is promising to promote chemical reactions at low temperatures.
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Affiliation(s)
- Shihui Dong
- Hefei National Research Center for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics , University of Science and Technology of China , Hefei , Anhui 230026 , China
| | - Bin Li
- Hefei National Research Center for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics , University of Science and Technology of China , Hefei , Anhui 230026 , China
| | - Xuefeng Cui
- Hefei National Research Center for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics , University of Science and Technology of China , Hefei , Anhui 230026 , China
| | - Shijing Tan
- Hefei National Research Center for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics , University of Science and Technology of China , Hefei , Anhui 230026 , China
| | - Bing Wang
- Hefei National Research Center for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics , University of Science and Technology of China , Hefei , Anhui 230026 , China
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Hao YN, Chen T, Zhang X, Zhou H, Ma Y. Ti-Ti σ bond at oxygen vacancy inducing the deep defect level in anatase TiO2 (101) surface. J Chem Phys 2019; 150:224702. [DOI: 10.1063/1.5108595] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Ya-nan Hao
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
| | - Tingwei Chen
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
| | - Xiao Zhang
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
| | - He Zhou
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
| | - Yuchen Ma
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
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Liu B, Zhao X, Yu J, Parkin IP, Fujishima A, Nakata K. Intrinsic intermediate gap states of TiO2 materials and their roles in charge carrier kinetics. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY C-PHOTOCHEMISTRY REVIEWS 2019. [DOI: 10.1016/j.jphotochemrev.2019.02.001] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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31
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Huang X, Wang J, Tao HB, Tian H, Xu H. An essential descriptor for the oxygen evolution reaction on reducible metal oxide surfaces. Chem Sci 2019; 10:3340-3345. [PMID: 30996921 PMCID: PMC6430015 DOI: 10.1039/c8sc04521f] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 02/01/2019] [Indexed: 11/23/2022] Open
Abstract
The number of excess electrons (NEE), as a descriptor, perfectly reproduces the OER volcano curve of TiO2(110) plotted using ΔGO – ΔGOH.
The development of a universal activity descriptor like the d-band model for transition metal catalysts is of great importance to catalyst design. However, due to the complicated electronic structures of metal oxides, the correlation of the binding energies of reaction intermediates (*OH, *O, and *OOH) in the oxygen evolution reaction (OER) with experimentally controllable properties of metal oxides has not been well established. Here we demonstrate that excess electrons are the essential factor that governs the binding properties of intermediates on the surfaces of reducible metal oxides. We propose that the number of excess electrons (NEE) is an essential activity descriptor toward the OER activities of these oxides, which perfectly reproduces the volcano curve plotted using the descriptor ΔGO – ΔGOH, so that tuning NEE can effectively tailor the OER activities of reducible metal oxide based catalysts. Guided by this descriptor, we predict a novel non-precious catalyst with an overpotential of 0.54 eV, which could be a potential alternative to current Ru or Ir based catalysts.
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Affiliation(s)
- Xiang Huang
- Department of Physics , Southern University of Science and Technology , Shenzhen 518055 , China . .,School of Physics and Technology , Wuhan University , Wuhan 430072 , China
| | - Jiong Wang
- School of Chemical and Biomedical Engineering , Nanyang Technological University , 62 Nanyang Drive , Singapore 637459 , Singapore
| | - Hua Bing Tao
- School of Chemical and Biomedical Engineering , Nanyang Technological University , 62 Nanyang Drive , Singapore 637459 , Singapore
| | - Hao Tian
- Department of Physics , Southern University of Science and Technology , Shenzhen 518055 , China .
| | - Hu Xu
- Department of Physics , Southern University of Science and Technology , Shenzhen 518055 , China .
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Sarkar A, Khan GG. The formation and detection techniques of oxygen vacancies in titanium oxide-based nanostructures. NANOSCALE 2019; 11:3414-3444. [PMID: 30734804 DOI: 10.1039/c8nr09666j] [Citation(s) in RCA: 125] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
TiO2 and other titanium oxide-based nanomaterials have drawn immense attention from researchers in different scientific domains due to their fascinating multifunctional properties, relative abundance, environmental friendliness, and bio-compatibility. However, the physical and chemical properties of titanium oxide-based nanomaterials are found to be explicitly dependent on the presence of various crystal defects. Oxygen vacancies are the most common among them and have always been the subject of both theoretical and experimental research as they play a crucial role in tuning the inherent properties of titanium oxides. This review highlights different strategies for effectively introducing oxygen vacancies in titanium oxide-based nanomaterials, as well as a discussion on the positions of oxygen vacancies inside the TiO2 band gap based on theoretical calculations. Additionally, a detailed review of different experimental techniques that are extensively used for identifying oxygen vacancies in TiO2 nanostructures is also presented.
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Affiliation(s)
- Ayan Sarkar
- Centre for Research in Nanoscience and Nanotechnology, University of Calcutta, Block-JD2, Sector-III, Salt Lake, Kolkata 700106, West Bengal, India.
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Leedahl B, de Boer T, Yuan X, Moewes A. Oxygen Vacancy Induced Structural Distortions in Black Titania: A Unique Approach using Soft X-ray EXAFS at the O-K Edge. Chemistry 2019; 25:3272-3278. [DOI: 10.1002/chem.201805423] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Indexed: 11/06/2022]
Affiliation(s)
- Brett Leedahl
- Department of Physics and Engineering Physics; University of Saskatchewan; 116 Science Place Saskatoon Saskatchewan S7N 5E2 Canada
| | - Tristan de Boer
- Department of Physics and Engineering Physics; University of Saskatchewan; 116 Science Place Saskatoon Saskatchewan S7N 5E2 Canada
| | - Xiaotao Yuan
- Beijing National Laboratory for Molecular Sciences and State Key, Laboratory of Rare Earth Materials Chemistry and Applications, College of, Chemistry and Molecular Engineering; Peking University; Beijing 100871 China
| | - Alexander Moewes
- Department of Physics and Engineering Physics; University of Saskatchewan; 116 Science Place Saskatoon Saskatchewan S7N 5E2 Canada
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34
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Kick M, Reuter K, Oberhofer H. Intricacies of DFT+U, Not Only in a Numeric Atom Centered Orbital Framework. J Chem Theory Comput 2019; 15:1705-1718. [DOI: 10.1021/acs.jctc.8b01211] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Matthias Kick
- Chair for Theoretical Chemistry and Catalysis Research Center, Technical University of Munich, Lichtenbergstrasse 4, Garching 85747, Germany
| | - Karsten Reuter
- Chair for Theoretical Chemistry and Catalysis Research Center, Technical University of Munich, Lichtenbergstrasse 4, Garching 85747, Germany
| | - Harald Oberhofer
- Chair for Theoretical Chemistry and Catalysis Research Center, Technical University of Munich, Lichtenbergstrasse 4, Garching 85747, Germany
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35
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Humphrey DS, Pang CL, Chen Q, Thornton G. Electron induced nanoscale engineering of rutile TiO 2 surfaces. NANOTECHNOLOGY 2019; 30:025303. [PMID: 30411713 DOI: 10.1088/1361-6528/aae95b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Electron stimulated modifications of the rutile TiO2(110) surface have been investigated using scanning tunnelling microscopy tip pulses and electron beam irradiation. Tip pulses on the 'as-prepared' surface induce local surface reconstruction and removal of surface hydroxyls in a region around the reconstruction. A defocused beam from an electron gun as well as tip pulses have been used to generate a number of oxygen deficient surfaces. All tip pulse features display an oval profile, which can be attributed to the anisotropic conductivity of the TiO2(110) surface. A novel oxygen deficient phase with well-ordered defective 'nano-cracks' has been identified, which can be produced by either electron beam irradiation or low flash anneal temperatures (∼570 K). Annealing such surfaces to moderate temperatures (∼850 K) leads to mixed 1 × 1 and 1 × 2 surfaces, until now only achievable by annealing in oxygen or ageing by repeated sputter/anneal cycles. Heating to normal preparation temperatures (1000 K) reforms the clean, well-ordered 1 × 1 surface termination. Our results demonstrate the potential of electron induced processes to modify the oxygen composition and structure of the TiO2(110) surface in a controllable and reversible way for selective surface patterning and surface reactivity modification.
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Affiliation(s)
- David S Humphrey
- London Centre for Nanotechnology and Chemistry Department, University College London, 17-19 Gordon Street, London, WC1H 0AJ, United Kingdom
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36
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Walenta CA, Kollmannsberger SL, Courtois C, Pereira RN, Stutzmann M, Tschurl M, Heiz U. Why co-catalyst-loaded rutile facilitates photocatalytic hydrogen evolution. Phys Chem Chem Phys 2019; 21:1491-1496. [DOI: 10.1039/c8cp05513k] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The photocatalytic H2 evolution on co-catalyst loaded titania is interpreted by a new mechanism, in which the co-catalyst acts as a recombination center for hydrogen and not as a reduction site of a photoreaction.
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Affiliation(s)
- Constantin A. Walenta
- Chair of Physical Chemistry
- Department of Chemistry & Catalysis Research Center
- Technische Universität München
- 85748 Garching
- Germany
| | - Sebastian L. Kollmannsberger
- Chair of Physical Chemistry
- Department of Chemistry & Catalysis Research Center
- Technische Universität München
- 85748 Garching
- Germany
| | - Carla Courtois
- Chair of Physical Chemistry
- Department of Chemistry & Catalysis Research Center
- Technische Universität München
- 85748 Garching
- Germany
| | - Rui N. Pereira
- Walter Schottky Institute and Physics Department
- Technische Universität München
- 85748 Garching
- Germany
| | - Martin Stutzmann
- Nanosystems Initiative Munich
- 80799 München
- Germany
- Walter Schottky Institute and Physics Department
- Technische Universität München
| | - Martin Tschurl
- Chair of Physical Chemistry
- Department of Chemistry & Catalysis Research Center
- Technische Universität München
- 85748 Garching
- Germany
| | - Ueli Heiz
- Chair of Physical Chemistry
- Department of Chemistry & Catalysis Research Center
- Technische Universität München
- 85748 Garching
- Germany
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37
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Wen B, Yin WJ, Selloni A, Liu LM. Defects, Adsorbates, and Photoactivity of Rutile TiO 2 (110): Insight by First-Principles Calculations. J Phys Chem Lett 2018; 9:5281-5287. [PMID: 30152233 DOI: 10.1021/acs.jpclett.8b02286] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We investigate the effect of adsorbates on the structure and photoabsorption of reduced TiO2 by first-principles calculations of rutile TiO2(110) in the presence of both titanium interstitials (Tiint's) and adsorbed water or methanol. Our results show that while Tiint's prefer to reside in deep inner layers when the surface is clean, they tend to diffuse toward the surface in the presence of water or methanol. This migration is due to the mutual stabilization of the adsorbates and Tiint defects in the near-surface region. We also find that adsorbed water/methanol changes the orbital character and localization sites of the excess electrons associated with the Tiint. These results can explain why the adsorption of water and methanol enhances the photoabsorption of the reduced TiO2(110) surface.
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Affiliation(s)
- Bo Wen
- Beijing Computational Science Research Center , Beijing 100193 , China
| | - Wen-Jin Yin
- School of Physics , Beihang University , Beijing 100191 , China
- School of Physics and Electronic Science , Hunan University of Science and Technology , Xiangtan 411201 , China
| | - Annabella Selloni
- Department of Chemistry , Princeton University , Princeton , New Jersey 08544 , United States
| | - Li-Min Liu
- Beijing Computational Science Research Center , Beijing 100193 , China
- School of Physics , Beihang University , Beijing 100191 , China
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38
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Gao Q, Chen H, Li K, Liu Q. Band Gap Engineering and Room-Temperature Ferromagnetism by Oxygen Vacancies in SrSnO 3 Epitaxial Films. ACS APPLIED MATERIALS & INTERFACES 2018; 10:27503-27509. [PMID: 30001107 DOI: 10.1021/acsami.8b08508] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Perovskite SrSnO3 (SSO) thin films were epitaxially grown on LaAlO3 (001) substrates by pulsed laser deposition at various oxygen pressures. X-ray diffraction was carried out to characterize the microstructure of the films, and the results showed that the unit-cell volume of the films increased gradually with lowering the growth oxygen pressures while remaining the perovskite structure. X-ray photoelectron spectroscopy results indicated that oxygen vacancies (OVs) existed in SSO thin films. Optical property measurements showed that all samples have a transmittance of more than 75% in the visible and near-infrared wavelength region. Furthermore, the band gaps of SSO films were found to increase from 4.56 to 5.21 eV with the decrease of deposition oxygen pressures calculated by linear fitting absorption edges of optical transmittance. In order to further ascertain the effect of OVs on band gaps of SSO films, the as-deposited 10 Pa film was annealed at 10-4 Pa oxygen pressures and the band gap was found to increase by more than 1 eV. Density functional theory was used to explain the effects of OVs on band gaps and the ferromagnetism of SSO films, and the results suggested that an impurity energy level of OVs appeared near the Fermi level, causing the widening of the band gaps, which is consistent with our experimental results. Meanwhile, the room-temperature ferromagnetism was observed in the SSO films, and saturation magnetization increased gradually from 4.46 to 7.69 emu/cm3 with decreasing the growth oxygen pressures.
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Affiliation(s)
- Qiang Gao
- School of Physics and Electronic Information , Huaibei Normal University , Huaibei 235000 , P. R. China
| | - Hengli Chen
- School of Material Science and Engineering , Hebei University of Technology , Tianjin 300130 , China
| | - Kaifeng Li
- School of Physics and Electronic Information , Huaibei Normal University , Huaibei 235000 , P. R. China
| | - Qinzhuang Liu
- School of Physics and Electronic Information , Huaibei Normal University , Huaibei 235000 , P. R. China
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39
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Tuning defects in oxides at room temperature by lithium reduction. Nat Commun 2018; 9:1302. [PMID: 29615620 PMCID: PMC5882908 DOI: 10.1038/s41467-018-03765-0] [Citation(s) in RCA: 166] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 03/09/2018] [Indexed: 12/21/2022] Open
Abstract
Defects can greatly influence the properties of oxide materials; however, facile defect engineering of oxides at room temperature remains challenging. The generation of defects in oxides is difficult to control by conventional chemical reduction methods that usually require high temperatures and are time consuming. Here, we develop a facile room-temperature lithium reduction strategy to implant defects into a series of oxide nanoparticles including titanium dioxide (TiO2), zinc oxide (ZnO), tin dioxide (SnO2), and cerium dioxide (CeO2). Our lithium reduction strategy shows advantages including all-room-temperature processing, controllability, time efficiency, versatility and scalability. As a potential application, the photocatalytic hydrogen evolution performance of defective TiO2 is examined. The hydrogen evolution rate increases up to 41.8 mmol g−1 h−1 under one solar light irradiation, which is ~3 times higher than that of the pristine nanoparticles. The strategy of tuning defect oxides used in this work may be beneficial for many other related applications. Defective oxides are attractive for energy conversion and storage applications, but it remains challenging to implant defects in oxides under mild conditions. Here, the authors develop a versatile lithium reduction strategy to engineer the defects of oxides at room temperature leading to enhanced photocatalytic properties.
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40
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Fe3O4-TiO2: Gd nanoparticles with enhanced photocatalytic activity and magnetic recyclability. POWDER TECHNOL 2018. [DOI: 10.1016/j.powtec.2017.11.049] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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41
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Zhang Y, Gan Y, Niu W, Norrman K, Yan X, Christensen DV, von Soosten M, Zhang H, Shen B, Pryds N, Sun J, Chen Y. Tuning the Two-Dimensional Electron Gas at Oxide Interfaces with Ti-O Configurations: Evidence from X-ray Photoelectron Spectroscopy. ACS APPLIED MATERIALS & INTERFACES 2018; 10:1434-1439. [PMID: 29226677 DOI: 10.1021/acsami.7b16510] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A chemical redox reaction can lead to a two-dimensional electron gas at the interface between a TiO2-terminated SrTiO3 (STO) substrate and an amorphous LaAlO3 capping layer. When replacing the STO substrate with rutile and anatase TiO2 substrates, considerable differences in the interfacial conduction are observed. On the basis of X-ray photoelectron spectroscopy (XPS) and transport measurements, we conclude that the interfacial conduction comes from redox reactions, and that the differences among the materials systems result mainly from variations in the activation energies for the diffusion of oxygen vacancies at substrate surfaces.
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Affiliation(s)
- Yu Zhang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences , Beijing 100190, Peoples' Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences , Beijing 100049, People's Republic of China
- Department of Energy Conversion and Storage, Technical University of Denmark , Risø Campus, 4000 Roskilde, Denmark
| | - Yulin Gan
- Department of Energy Conversion and Storage, Technical University of Denmark , Risø Campus, 4000 Roskilde, Denmark
| | - Wei Niu
- Department of Energy Conversion and Storage, Technical University of Denmark , Risø Campus, 4000 Roskilde, Denmark
| | - Kion Norrman
- Department of Energy Conversion and Storage, Technical University of Denmark , Risø Campus, 4000 Roskilde, Denmark
| | - Xi Yan
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences , Beijing 100190, Peoples' Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences , Beijing 100049, People's Republic of China
| | - Dennis Valbjørn Christensen
- Department of Energy Conversion and Storage, Technical University of Denmark , Risø Campus, 4000 Roskilde, Denmark
| | - Merlin von Soosten
- Department of Energy Conversion and Storage, Technical University of Denmark , Risø Campus, 4000 Roskilde, Denmark
| | - Hongrui Zhang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences , Beijing 100190, Peoples' Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences , Beijing 100049, People's Republic of China
| | - Baogen Shen
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences , Beijing 100190, Peoples' Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences , Beijing 100049, People's Republic of China
| | - Nini Pryds
- Department of Energy Conversion and Storage, Technical University of Denmark , Risø Campus, 4000 Roskilde, Denmark
| | - Jirong Sun
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences , Beijing 100190, Peoples' Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences , Beijing 100049, People's Republic of China
| | - Yunzhong Chen
- Department of Energy Conversion and Storage, Technical University of Denmark , Risø Campus, 4000 Roskilde, Denmark
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Hao QQ, Wang ZQ, Dai DX, Zhou CY, Yang XM. Photoelectron Spectroscopic Study of Methanol Adsorbed Rutile TiO2(110) Surface. CHINESE J CHEM PHYS 2017. [DOI: 10.1063/1674-0068/30/cjcp1711219] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Qun-qing Hao
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian 116023, China
| | - Zhi-qiang Wang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian 116023, China
- School of Physics and Optoelectronic Engineering, Xidian University, Xi'an 710071 China
| | - Dong-xu Dai
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian 116023, China
| | - Chuan-yao Zhou
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian 116023, China
| | - Xue-ming Yang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian 116023, China
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43
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Wang R, Fan H. The location of excess electrons on H2O/TiO2(110) surface and its role in the surface reactions. Mol Phys 2017. [DOI: 10.1080/00268976.2017.1371801] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Ruimin Wang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, P. R. China
- University of Chinese Academy of Sciences, 19 A Yuquan Road, Beijing, P. R. China
| | - Hongjun Fan
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, P. R. China
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44
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Han B, Hang Hu Y. Investigation on H-containing shallow trap of hydrogenated TiO 2 with in situ Fourier transform infrared diffuse reflection spectroscopy. NANOTECHNOLOGY 2017; 28:304001. [PMID: 28598336 DOI: 10.1088/1361-6528/aa787c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A novel technique, high temperature high pressure in situ Fourier transform infrared diffuse reflection spectroscopy, was successfully used to investigate the formation and stability of shallow trap states in P25 TiO2 nanoparticles. Two types of shallow traps (with and without H atoms) were identified. The H-containing shallow trap can be easily generated by heating in H2 atmosphere. However, the trap is unstable in vacuum at 600 °C. In contrast, the H-free shallow trap, which can be formed by heating in vacuum, is stable even at 600 °C. The energy gaps between shallow trap states and the conduction band are 0.09 eV for H-containing shallow trap and 0.13 eV for H-free shallow trap, indicating that the H-containing shallow trap state is closer to the conduction band than that without H.
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Affiliation(s)
- Bing Han
- Department of Materials Science and Engineering, Michigan Technological University, 1400 Townsend Drive, Houghton, MI-49931-1295, United States of America
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Gobaut B, Orgiani P, Sambri A, di Gennaro E, Aruta C, Borgatti F, Lollobrigida V, Céolin D, Rueff JP, Ciancio R, Bigi C, Das PK, Fujii J, Krizmancic D, Torelli P, Vobornik I, Rossi G, Miletto Granozio F, Scotti di Uccio U, Panaccione G. Role of Oxygen Deposition Pressure in the Formation of Ti Defect States in TiO 2(001) Anatase Thin Films. ACS APPLIED MATERIALS & INTERFACES 2017; 9:23099-23106. [PMID: 28613812 DOI: 10.1021/acsami.7b03181] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We report the study of anatase TiO2(001)-oriented thin films grown by pulsed laser deposition on LaAlO3(001). A combination of in situ and ex situ methods has been used to address both the origin of the Ti3+-localized states and their relationship with the structural and electronic properties on the surface and the subsurface. Localized in-gap states are analyzed using resonant X-ray photoelectron spectroscopy and are related to the Ti3+ electronic configuration, homogeneously distributed over the entire film thickness. We find that an increase in the oxygen pressure corresponds to an increase in Ti3+ only in a well-defined range of deposition pressure; outside this range, Ti3+ and the strength of the in-gap states are reduced.
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Affiliation(s)
- Benoit Gobaut
- Elettra Sincrotrone Trieste S.c.p.A. , Basovizza, I-34012 Trieste, Italy
| | | | - Alessia Sambri
- CNR-SPIN, UOS Napoli , I-80126 Napoli, Italy
- Department of Physics, University of Napoli Federico II , I-80126 Napoli, Italy
| | - Emiliano di Gennaro
- CNR-SPIN, UOS Napoli , I-80126 Napoli, Italy
- Department of Physics, University of Napoli Federico II , I-80126 Napoli, Italy
| | - Carmela Aruta
- CNR-SPIN, UOS Napoli , I-80126 Napoli, Italy
- Department of Physics, University of Napoli Federico II , I-80126 Napoli, Italy
| | | | | | - Denis Céolin
- Synchrotron SOLEIL , L'Orme des Merisiers, BP 48, Saint Aubin, 91192 Gif sur Yvette, France
| | - Jean-Pascal Rueff
- Synchrotron SOLEIL , L'Orme des Merisiers, BP 48, Saint Aubin, 91192 Gif sur Yvette, France
- Laboratoire de Chimie Physique-Matière et Rayonnement, UPMC Université; Paris 06, CNRS, UMR 7614 , F-75005 Paris, France
| | | | - Chiara Bigi
- CNR-IOM, Laboratorio TASC , I-34149 Trieste, Italy
- Department of Physics, University of Milano , I-20133 Milano, Italy
| | - Pranab Kumar Das
- CNR-IOM, Laboratorio TASC , I-34149 Trieste, Italy
- International Centre for Theoretical Physics (ICTP) , I-34100 Trieste, Italy
| | - Jun Fujii
- CNR-IOM, Laboratorio TASC , I-34149 Trieste, Italy
| | | | | | | | - Giorgio Rossi
- CNR-IOM, Laboratorio TASC , I-34149 Trieste, Italy
- Department of Physics, University of Milano , I-20133 Milano, Italy
| | - Fabio Miletto Granozio
- CNR-SPIN, UOS Napoli , I-80126 Napoli, Italy
- Department of Physics, University of Napoli Federico II , I-80126 Napoli, Italy
| | - Umberto Scotti di Uccio
- CNR-SPIN, UOS Napoli , I-80126 Napoli, Italy
- Department of Physics, University of Napoli Federico II , I-80126 Napoli, Italy
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46
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Spectroscopic and kinetic insights of Pt-dispersion over microwave-synthesized GO-supported Pt-TiO 2 for CO oxidation. MOLECULAR CATALYSIS 2017. [DOI: 10.1016/j.mcat.2017.01.014] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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47
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Hussain H, Tocci G, Woolcot T, Torrelles X, Pang CL, Humphrey DS, Yim CM, Grinter DC, Cabailh G, Bikondoa O, Lindsay R, Zegenhagen J, Michaelides A, Thornton G. Structure of a model TiO 2 photocatalytic interface. NATURE MATERIALS 2017; 16:461-466. [PMID: 27842073 DOI: 10.1038/nmat4793] [Citation(s) in RCA: 117] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 10/06/2016] [Indexed: 05/21/2023]
Abstract
The interaction of water with TiO2 is crucial to many of its practical applications, including photocatalytic water splitting. Following the first demonstration of this phenomenon 40 years ago there have been numerous studies of the rutile single-crystal TiO2(110) interface with water. This has provided an atomic-level understanding of the water-TiO2 interaction. However, nearly all of the previous studies of water/TiO2 interfaces involve water in the vapour phase. Here, we explore the interfacial structure between liquid water and a rutile TiO2(110) surface pre-characterized at the atomic level. Scanning tunnelling microscopy and surface X-ray diffraction are used to determine the structure, which is comprised of an ordered array of hydroxyl molecules with molecular water in the second layer. Static and dynamic density functional theory calculations suggest that a possible mechanism for formation of the hydroxyl overlayer involves the mixed adsorption of O2 and H2O on a partially defected surface. The quantitative structural properties derived here provide a basis with which to explore the atomistic properties and hence mechanisms involved in TiO2 photocatalysis.
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Affiliation(s)
- H Hussain
- London Centre for Nanotechnology and Department of Chemistry, University College London, 20 Gordon Street, London WC1H OAJ, UK
- ESRF, 6 rue Jules Horowitz, F-38000 Grenoble cedex, France
| | - G Tocci
- London Centre for Nanotechnology and Department of Chemistry, University College London, 20 Gordon Street, London WC1H OAJ, UK
| | - T Woolcot
- London Centre for Nanotechnology and Department of Chemistry, University College London, 20 Gordon Street, London WC1H OAJ, UK
| | - X Torrelles
- Institut de Ciència de Materials de Barcelona (CSIC), Campus UAB, 08193 Bellaterra, Spain
| | - C L Pang
- London Centre for Nanotechnology and Department of Chemistry, University College London, 20 Gordon Street, London WC1H OAJ, UK
| | - D S Humphrey
- London Centre for Nanotechnology and Department of Chemistry, University College London, 20 Gordon Street, London WC1H OAJ, UK
| | - C M Yim
- London Centre for Nanotechnology and Department of Chemistry, University College London, 20 Gordon Street, London WC1H OAJ, UK
| | - D C Grinter
- London Centre for Nanotechnology and Department of Chemistry, University College London, 20 Gordon Street, London WC1H OAJ, UK
| | - G Cabailh
- Sorbonne Universités, UPMC Univ Paris 06, CNRS-UMR 7588, Institut des NanoSciences de Paris, F-75005 Paris, France
| | - O Bikondoa
- Department of Physics, University of Warwick, Gibbet Hill Road, Coventry C4 7AL, UK
| | - R Lindsay
- Corrosion and Protection Centre, School of Materials, The University of Manchester, Sackville Street, Manchester M13 9PL, UK
| | - J Zegenhagen
- ESRF, 6 rue Jules Horowitz, F-38000 Grenoble cedex, France
| | - A Michaelides
- London Centre for Nanotechnology and Department of Chemistry, University College London, 20 Gordon Street, London WC1H OAJ, UK
| | - G Thornton
- London Centre for Nanotechnology and Department of Chemistry, University College London, 20 Gordon Street, London WC1H OAJ, UK
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48
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Liu G, Chen T, Liu X, Jin F, Yuan S, Ma Y. Electronic structures of rutile (011)(2 × 1) surfaces: A many-body perturbation theory study. J Chem Phys 2017; 146:124702. [DOI: 10.1063/1.4978793] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Guokui Liu
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
| | - Tingwei Chen
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
| | - Xiaobiao Liu
- School of Physics and State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
| | - Fan Jin
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
| | - Shiling Yuan
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
| | - Yuchen Ma
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
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49
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Batalović K, Bundaleski N, Radaković J, Abazović N, Mitrić M, Silva RA, Savić M, Belošević-Čavor J, Rakočević Z, Rangel CM. Modification of N-doped TiO 2 photocatalysts using noble metals (Pt, Pd) - a combined XPS and DFT study. Phys Chem Chem Phys 2017; 19:7062-7071. [PMID: 28225131 DOI: 10.1039/c7cp00188f] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Nitrogen-doped TiO2 (N-TiO2) is considered as one of the most promising materials for various photocatalytic applications, while noble metals Pd and Pt are known as good catalysts for hydrogen evolution. This work focuses on the determination of structural and electronic modifications of N-TiO2, achieved by noble metal deposition at the surface, as a starting indicator for potential applications. We focus on the properties of easily synthesized nanocrystalline nitrogen-doped anatase TiO2, modified by depositing small amounts of Pd (0.05 wt%) and Pt (0.10 wt%), aiming to demonstrate efficient enhancement of optical properties. The chemical states of dopants are studied in detail, using X-ray photoemission spectroscopy, to address the potential of N-TiO2 to act as a support for metallic nanoparticles. DFT calculations are used to resolve substitutional from interstitial nitrogen doping of anatase TiO2, as well as to study the combined effect of nitrogen doping and oxygen vacancy formation. Based on the binding energies calculated using Slater's transition state theory, dominant contribution to the N 1s binding energy at 399.8 eV is ascribed to interstitially doped nitrogen in anatase TiO2. Given that both structure and photocatalytic properties depend greatly on the synthesis procedure, this work contributes further to establishing correlation between the structure and optical properties of the noble metal modified N-TiO2 system.
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Affiliation(s)
- K Batalović
- Institute of Nuclear Sciences Vinča, University of Belgrade, P.O. Box 522, 11001 Belgrade, Serbia.
| | - N Bundaleski
- Institute of Nuclear Sciences Vinča, University of Belgrade, P.O. Box 522, 11001 Belgrade, Serbia.
| | - J Radaković
- Institute of Nuclear Sciences Vinča, University of Belgrade, P.O. Box 522, 11001 Belgrade, Serbia.
| | - N Abazović
- Institute of Nuclear Sciences Vinča, University of Belgrade, P.O. Box 522, 11001 Belgrade, Serbia.
| | - M Mitrić
- Institute of Nuclear Sciences Vinča, University of Belgrade, P.O. Box 522, 11001 Belgrade, Serbia.
| | - R A Silva
- LNEG, National Laboratory for Energy and Geology, Paço do Lumiar 22, 1649-038 Lisbon, Portugal
| | - M Savić
- Institute of Nuclear Sciences Vinča, University of Belgrade, P.O. Box 522, 11001 Belgrade, Serbia.
| | - J Belošević-Čavor
- Institute of Nuclear Sciences Vinča, University of Belgrade, P.O. Box 522, 11001 Belgrade, Serbia.
| | - Z Rakočević
- Institute of Nuclear Sciences Vinča, University of Belgrade, P.O. Box 522, 11001 Belgrade, Serbia.
| | - C M Rangel
- LNEG, National Laboratory for Energy and Geology, Paço do Lumiar 22, 1649-038 Lisbon, Portugal
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50
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Xu CQ, Lee MS, Wang YG, Cantu DC, Li J, Glezakou VA, Rousseau R. Structural Rearrangement of Au-Pd Nanoparticles under Reaction Conditions: An ab Initio Molecular Dynamics Study. ACS NANO 2017; 11:1649-1658. [PMID: 28121422 DOI: 10.1021/acsnano.6b07409] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The structure, composition, and atomic distribution of nanoalloys under operating conditions are of significant importance for their catalytic activity. In the present work, we use ab initio molecular dynamics simulations to understand the structural behavior of Au-Pd nanoalloys supported on rutile TiO2 under different conditions. We find that the Au-Pd structure is strongly dependent on the redox properties of the support, originating from strong metal-support interactions. Under reducing conditions, Pd atoms are inclined to move toward the metal/oxide interface, as indicated by a significant increase of Pd-Ti bonds. This could be attributed to the charge localization at the interface that leads to Coulomb attractions to positively charged Pd atoms. In contrast, under oxidizing conditions, Pd atoms would rather stay inside or on the exterior of the nanoparticle. Moreover, Pd atoms on the alloy surface can be stabilized by hydrogen adsorption, forming Pd-H bonds, which are stronger than Au-H bonds. Our work offers critical insights into the structure and redox properties of Au-Pd nanoalloy catalysts under working conditions.
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Affiliation(s)
- Cong-Qiao Xu
- Department of Chemistry, Tsinghua University , Beijing 100084, China
| | | | | | | | - Jun Li
- Department of Chemistry, Tsinghua University , Beijing 100084, China
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