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Jiao X, Dong W, Shi M, Wang H, Ding C, Wei Z, Gong G, Li Y, Li Y, Zuo B, Wang J, Zhang D, Pan M, Wang L, Xue QK. Significantly enhanced superconductivity in monolayer FeSe films on SrTiO 3(001) via metallic δ-doping. Natl Sci Rev 2024; 11:nwad213. [PMID: 38312379 PMCID: PMC10833465 DOI: 10.1093/nsr/nwad213] [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: 04/20/2023] [Revised: 07/19/2023] [Accepted: 07/25/2023] [Indexed: 02/06/2024] Open
Abstract
Superconductivity transition temperature (Tc) marks the inception of a macroscopic quantum phase-coherent paired state in fermionic systems. For 2D superconductivity, the paired electrons condense into a coherent superfluid state at Tc, which is usually lower than the pairing temperature, between which intrinsic physics including Berezinskii-Kosterlitz-Thouless transition and pseudogap state are hotly debated. In the case of monolayer FeSe superconducting films on SrTiO3(001), although the pairing temperature (Tp) is revealed to be 65-83 K by using spectroscopy characterization, the measured zero-resistance temperature ([Formula: see text]) is limited to 20 K. Here, we report significantly enhanced superconductivity in monolayer FeSe films by δ-doping of Eu or Al on SrTiO3(001) surface, in which [Formula: see text] is enhanced by 12 K with a narrowed transition width ΔTc ∼ 8 K, compared with non-doped samples. Using scanning tunneling microscopy/spectroscopy measurements, we demonstrate lowered work function of the δ-doped SrTiO3(001) surface and enlarged superconducting gaps in the monolayer FeSe with improved morphology/electronic homogeneity. Our work provides a practical route to enhance 2D superconductivity by using interface engineering.
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Affiliation(s)
- Xiaotong Jiao
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China
- School of Physics & Information Technology, Shaanxi Normal University, Xi'an 710119, China
| | - Wenfeng Dong
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China
| | - Mingxia Shi
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China
| | - Heng Wang
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China
| | - Cui Ding
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
| | - Zhongxu Wei
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China
- Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Guanming Gong
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China
| | - Yanan Li
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
- Department of Physics, The Pennsylvania State University, University Park, PA 16802, USA
| | - Yuanzhao Li
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China
| | - Binjie Zuo
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China
| | - Jian Wang
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
- Collaborative Innovation Center of Quantum Matter, Beijing 100871, China
- Hefei National Laboratory, Hefei 230088, China
| | - Ding Zhang
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China
| | - Minghu Pan
- School of Physics & Information Technology, Shaanxi Normal University, Xi'an 710119, China
| | - Lili Wang
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China
| | - Qi-Kun Xue
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
- Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
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2
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Yuan W, Chen B, Han ZK, You R, Jiang Y, Qi R, Li G, Wu H, Ganduglia-Pirovano MV, Wang Y. Direct in-situ insights into the asymmetric surface reconstruction of rutile TiO 2 (110). Nat Commun 2024; 15:1616. [PMID: 38388567 PMCID: PMC10883989 DOI: 10.1038/s41467-024-46011-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 02/09/2024] [Indexed: 02/24/2024] Open
Abstract
The reconstruction of rutile TiO2 (110) holds significant importance as it profoundly influences the surface chemistry and catalytic properties of this widely used material in various applications, from photocatalysis to solar energy conversion. Here, we directly observe the asymmetric surface reconstruction of rutile TiO2 (110)-(1×2) with atomic-resolution using in situ spherical aberration-corrected scanning transmission electron microscopy. Density functional theory calculations were employed to complement the experimental observations. Our findings highlight the pivotal role played by repulsive electrostatic interaction among the small polarons -formed by excess electrons following the removal of neutral oxygen atoms- and the subsequent surface relaxations induced by these polarons. The emergence and disappearance of these asymmetric structures can be controlled by adjusting the oxygen partial pressure. This research provides a deeper understanding, prediction, and manipulation of the surface reconstructions of rutile TiO2 (110), holding implications for a diverse range of applications and technological advancements involving rutile-based materials.
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Affiliation(s)
- Wentao Yuan
- Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, 310027, Hangzhou, China
- Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering, 030000, Taiyuan, China
| | - Bingwei Chen
- Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, 310027, Hangzhou, China
| | - Zhong-Kang Han
- Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, 310027, Hangzhou, China.
- Fritz Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195, Berlin, Germany.
| | - Ruiyang You
- Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, 310027, Hangzhou, China
| | - Ying Jiang
- Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, 310027, Hangzhou, China
| | - Rui Qi
- Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, 310027, Hangzhou, China
| | - Guanxing Li
- Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, 310027, Hangzhou, China
| | - Hanglong Wu
- Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, 310027, Hangzhou, China
| | | | - Yong Wang
- Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, 310027, Hangzhou, 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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Gaberle J, Shluger A. The role of surface reduction in the formation of Ti interstitials. RSC Adv 2019; 9:12182-12188. [PMID: 35515850 PMCID: PMC9063666 DOI: 10.1039/c9ra01015g] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 03/26/2019] [Indexed: 11/21/2022] Open
Abstract
Density functional theory simulations are used to investigate the formation and mobility of Ti interstitial ions, Tii, at the (110) surface of rutile TiO2.
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Affiliation(s)
- Julian Gaberle
- Department of Physics and Astronomy
- University College London
- WC1E 6BT London
- UK
| | - Alexander Shluger
- Department of Physics and Astronomy
- University College London
- WC1E 6BT London
- UK
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5
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Xu M, Shao S, Gao B, Lv J, Li Q, Wang Y, Wang H, Zhang L, Ma Y. Anatase (101)-like Structural Model Revealed for Metastable Rutile TiO 2(011) Surface. ACS APPLIED MATERIALS & INTERFACES 2017; 9:7891-7896. [PMID: 28230969 DOI: 10.1021/acsami.6b16449] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Titanium dioxide has been widely used as an efficient transition metal oxide photocatalyst. However, its photocatalytic activity is limited to the ultraviolet spectrum range due to the large bandgap beyond 3 eV. Efforts to reduce the bandgap to achieve a broader spectrum range of light absorption have been successfully attempted via the experimental synthesis of dopant-free metastable surface structures of rutile-type TiO2 (011) 2 × 1. This new surface phase possesses a reduced bandgap of ∼2.1 eV, showing great potential for an excellent photocatalyst covering a wide range of visible light. There is a need to establish the atomistic structure of this metastable surface to understand the physical cause for the bandgap reduction and to improve the future design of photocatalysts. Here, we report computational investigations in an effort to unravel this surface structure via swarm structure-searching simulations. The established structure adopts the anatase (101)-like structure model, where the topmost 2-fold O atoms form a quasi-hexagonal surface pattern and bond with the unsaturated 5-fold and 4-fold Ti atoms in the next layer. The predicted anatase (101)-like surface model can naturally explain the experimental observation of the STM images, the electronic bandgap, and the oxidation state of Ti4+. Dangling bonds on the anatase (101)-like surface are abundant making it a superior photocatalyst. First-principles molecular dynamics simulations have supported the high photocatalytic activity by showing that water and formic acid molecules dissociate spontaneously on the anatase (101)-like surface.
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Affiliation(s)
- Meiling Xu
- Beijing Computational Science Research Center , Beijing 100084, China
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Zhou R, Li D, Qu B, Sun X, Zhang B, Zeng XC. Rutile TiO 2(011)-2 × 1 Reconstructed Surfaces with Optical Absorption over the Visible Light Spectrum. ACS APPLIED MATERIALS & INTERFACES 2016; 8:27403-27410. [PMID: 27653160 DOI: 10.1021/acsami.6b10718] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The stable structures of the reconstructed rutile TiO2(011) surface are explored based on an evolutionary method. In addition to the well-known "brookite(001)-like" 2 × 1 reconstruction model, three 2 × 1 reconstruction structures are revealed for the first time, all being more stable in the high Ti-rich condition. Importantly, the predicted Ti4O4-2 × 1 surface model not only is in excellent agreement with the reconstructed metastable surface detected by Tao et al. [Nat. Chem. 3, 296 (2011)] from their STM experiment but also gives a consistent formation mechanism and electronic structures with the measured surface. The computed imaginary part of the dielectric function suggests that the newly predicted reconstructed surfaces are capable of optical absorption over the entire visible light spectrum, thereby offering high potential for photocatalytic applications.
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Affiliation(s)
- Rulong Zhou
- Laboratory of Amorphous Materials, School of Materials Science and Engineering, Hefei University of Technology , Hefei, Anhui 230009, China
| | - Dongdong Li
- Laboratory of Amorphous Materials, School of Materials Science and Engineering, Hefei University of Technology , Hefei, Anhui 230009, China
| | - Bingyan Qu
- Laboratory of Amorphous Materials, School of Materials Science and Engineering, Hefei University of Technology , Hefei, Anhui 230009, China
| | - Xiaorui Sun
- Laboratory of Amorphous Materials, School of Materials Science and Engineering, Hefei University of Technology , Hefei, Anhui 230009, China
| | - Bo Zhang
- Laboratory of Amorphous Materials, School of Materials Science and Engineering, Hefei University of Technology , Hefei, Anhui 230009, China
| | - Xiao Cheng Zeng
- Department of Chemistry and Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln , Lincoln, Nebraska 68588, United States
- Hefei National Laboratory for Physical Sciences at Microscale and Collaborative Innovation Center of Chemistry for Energy Materials, University of Science and Technology of China , Hefei, Anhui 230026, China
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7
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Miccio LA, Setvin M, Müller M, Abadía M, Piquero I, Lobo-Checa J, Schiller F, Rogero C, Schmid M, Sánchez-Portal D, Diebold U, Ortega JE. Interplay between Steps and Oxygen Vacancies on Curved TiO2(110). NANO LETTERS 2016; 16:2017-22. [PMID: 26752001 DOI: 10.1021/acs.nanolett.5b05286] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
A vicinal rutile TiO2(110) crystal with a smooth variation of atomic steps parallel to the [1-10] direction was analyzed locally with STM and ARPES. The step edge morphology changes across the samples, from [1-11] zigzag faceting to straight [1-10] steps. A step-bunching phase is attributed to an optimal (110) terrace width, where all bridge-bonded O atom vacancies (Obr vacs) vanish. The [1-10] steps terminate with a pair of 2-fold coordinated O atoms, which give rise to bright, triangular protrusions (St) in STM. The intensity of the Ti 3d-derived gap state correlates with the sum of Obr vacs plus St protrusions at steps, suggesting that both Obr vacs and steps contribute a similar effective charge to sample doping. The binding energy of the gap state shifts when going from the flat (110) surface toward densely stepped planes, pointing to differences in the Ti(3+) polaron near steps and at terraces.
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Affiliation(s)
- Luis A Miccio
- Centro de Física de Materiales (CSIC-UPV/EHU) , Manuel Lardizabal 5, 20018 San Sebastián, Spain
- Donostia International Physics Center (DIPC) , 20018 San Sebastián, Spain
| | - Martin Setvin
- Institute of Applied Physics, Vienna University of Technology , Wiedner Hauptstrasse 8-10/134, 1040 Vienna, Austria
| | - Moritz Müller
- CIC nanoGUNE , Avenido Tolosa 76, 20018 San Sebastián, Spain
| | - Mikel Abadía
- Centro de Física de Materiales (CSIC-UPV/EHU) , Manuel Lardizabal 5, 20018 San Sebastián, Spain
| | - Ignacio Piquero
- Centro de Física de Materiales (CSIC-UPV/EHU) , Manuel Lardizabal 5, 20018 San Sebastián, Spain
| | - Jorge Lobo-Checa
- Centro de Física de Materiales (CSIC-UPV/EHU) , Manuel Lardizabal 5, 20018 San Sebastián, Spain
| | - Frederik Schiller
- Centro de Física de Materiales (CSIC-UPV/EHU) , Manuel Lardizabal 5, 20018 San Sebastián, Spain
- Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität Marburg , 35032 Marburg, Germany
| | - Celia Rogero
- Centro de Física de Materiales (CSIC-UPV/EHU) , Manuel Lardizabal 5, 20018 San Sebastián, Spain
| | - Michael Schmid
- Institute of Applied Physics, Vienna University of Technology , Wiedner Hauptstrasse 8-10/134, 1040 Vienna, Austria
| | - Daniel Sánchez-Portal
- Centro de Física de Materiales (CSIC-UPV/EHU) , Manuel Lardizabal 5, 20018 San Sebastián, Spain
- Donostia International Physics Center (DIPC) , 20018 San Sebastián, Spain
| | - Ulrike Diebold
- Institute of Applied Physics, Vienna University of Technology , Wiedner Hauptstrasse 8-10/134, 1040 Vienna, Austria
| | - J Enrique Ortega
- Centro de Física de Materiales (CSIC-UPV/EHU) , Manuel Lardizabal 5, 20018 San Sebastián, Spain
- Donostia International Physics Center (DIPC) , 20018 San Sebastián, Spain
- Departamento de Física Aplicada, Universidad del País Vasco (UPV/EHU) , 20080 San Sebastián, Spain
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Wang C, Fan Q, Han Y, Martínez JI, Martín-Gago JA, Wang W, Ju H, Gottfried JM, Zhu J. Metalation of tetraphenylporphyrin with nickel on a TiO2(110)-1 × 2 surface. NANOSCALE 2016; 8:1123-1132. [PMID: 26667953 PMCID: PMC4693967 DOI: 10.1039/c5nr03134f] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The in situ metalation of tetraphenylporphyrin (2HTPP) with Ni on the reconstructed TiO2(110)-1 × 2 surface, resulting in the formation of adsorbed nickel(II)-tetraphenylporphyrin (NiTPP), has been investigated by synchrotron radiation photoemission spectroscopy (SRPES), scanning tunnelling microscopy (STM) and ab initio Density Functional Theory (DFT) calculations. The metalation can be realized at room temperature irrespective of the deposition order of Ni and 2HTPP, which however leads to different metalation degrees. Increasing the substrate temperature or Ni : 2HTPP ratio results in higher metalation degree, which ultimately reaches its limit at ∼85% (Ni : 2HTPP = 3 : 1) and ∼49% (Ni : 2HTPP = 1 : 1) for post- and pre-deposition of Ni, respectively. The reaction from 2HTPP to NiTPP is accompanied by changes of the molecular adsorption conformation and the adsorption site from a tilted two-lobed feature on added Ti2O3 rows to a four-lobed feature on top of troughs or cross-links of the TiO2(110)-1 × 2 surface. This interpretation of the STM data is supported by DFT-based STM simulations.
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Affiliation(s)
- Cici Wang
- National Synchrotron Radiation Laboratory and Collaborative Innovation Center of Suzhou Nano Science and Technology, University of Science and Technology of China, Hefei, 230029, P. R. China
| | - Qitang Fan
- National Synchrotron Radiation Laboratory and Collaborative Innovation Center of Suzhou Nano Science and Technology, University of Science and Technology of China, Hefei, 230029, P. R. China
| | - Yong Han
- National Synchrotron Radiation Laboratory and Collaborative Innovation Center of Suzhou Nano Science and Technology, University of Science and Technology of China, Hefei, 230029, P. R. China
| | - José I. Martínez
- ESISNA Group, Dept. Surfaces, Coatings and Molecular Astrophysics, Institute of Material Science of Madrid (ICMM-CSIC), Sor Juana Inés de la Cruz, 3, 28049, Madrid, Spain
| | - José A. Martín-Gago
- ESISNA Group, Dept. Surfaces, Coatings and Molecular Astrophysics, Institute of Material Science of Madrid (ICMM-CSIC), Sor Juana Inés de la Cruz, 3, 28049, Madrid, Spain
| | - Weijia Wang
- National Synchrotron Radiation Laboratory and Collaborative Innovation Center of Suzhou Nano Science and Technology, University of Science and Technology of China, Hefei, 230029, P. R. China
| | - Huanxin Ju
- National Synchrotron Radiation Laboratory and Collaborative Innovation Center of Suzhou Nano Science and Technology, University of Science and Technology of China, Hefei, 230029, P. R. China
| | - J. Michael Gottfried
- Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Str. 4, 35032, Marburg, Germany
| | - Junfa Zhu
- National Synchrotron Radiation Laboratory and Collaborative Innovation Center of Suzhou Nano Science and Technology, University of Science and Technology of China, Hefei, 230029, P. R. China
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Sheng X, Chen L, Xu T, Zhu K, Feng X. Understanding and removing surface states limiting charge transport in TiO 2 nanowire arrays for enhanced optoelectronic device performance. Chem Sci 2015; 7:1910-1913. [PMID: 29899914 PMCID: PMC5966746 DOI: 10.1039/c5sc04076k] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 12/08/2015] [Indexed: 12/04/2022] Open
Abstract
An effective wet-chemistry approach is demonstrated to minimize the trap states that limit electron transport in rutile TiO2 nanowire arrays, this leads to an over 20-fold enhancement in the electron diffusion coefficient.
Charge transport within electrode materials plays a key role in determining the optoelectronic device performance. Aligned single-crystal TiO2 nanowire arrays offer an ideal electron transport path and are expected to have higher electron mobility. Unfortunately, their transport is found not to be superior to that in nanoparticle films. Here we show that the low electron transport in rutile TiO2 nanowires is mainly caused by surface traps in relatively deep energy levels, which cannot be removed by conventional approaches, such as oxygen annealing treatment. Moreover, we demonstrate an effective wet-chemistry approach to minimize these trap states, leading to over 20-fold enhancement in electron diffusion coefficient and 62% improvement in solar cell performance. On the basis of our results, the potential of TiO2 NWs can be developed and well-utilized, which is significantly important for their practical applications.
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Affiliation(s)
- Xia Sheng
- College of Chemistry , Chemical Engineering and Materials Science , Soochow University , Suzhou 215123 , P. R. China .
| | - Liping Chen
- College of Chemistry , Chemical Engineering and Materials Science , Soochow University , Suzhou 215123 , P. R. China .
| | - Tao Xu
- Department of Chemistry and Biochemistry , Northern Illinois University , DeKalb , Illinois 60115 , USA
| | - Kai Zhu
- National Renewable Energy Laboratory , 1617 Cole Boulevard, Golden , Colorado 80401 , USA
| | - Xinjian Feng
- College of Chemistry , Chemical Engineering and Materials Science , Soochow University , Suzhou 215123 , P. R. China .
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Wang Q, Oganov AR, Zhu Q, Zhou XF. New reconstructions of the (110) surface of rutile TiO2 predicted by an evolutionary method. PHYSICAL REVIEW LETTERS 2014; 113:266101. [PMID: 25615358 DOI: 10.1103/physrevlett.113.266101] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2014] [Indexed: 06/04/2023]
Abstract
Reconstructions of the (110) surface of rutile TiO2 (the dominant surface of this important mineral and catalyst) are investigated using the evolutionary approach, resolving previous controversies. Depending on thermodynamic conditions, four different stable reconstructions are observed for this surface. We confirm the recently proposed "Ti2O3-(1×2)" and "Ti2O-(1×2)" reconstructions and predict two new reconstructions "Ti3O2-(1×2)" and "Ti3O3-(2×1)," which match experimental results. Furthermore, we find that surface electronic states are sensitive to reconstructions and, therefore, depend on thermodynamic conditions.
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Affiliation(s)
- Qinggao Wang
- Moscow Institute of Physics and Technology, 9 Institutskiy Lane, Dolgoprudny City, Moscow Region 141700, Russia and Department of Physics and Electrical Engineering, Anyang Normal University, Anyang, Henan Province 455000, People's Republic of China
| | - Artem R Oganov
- Moscow Institute of Physics and Technology, 9 Institutskiy Lane, Dolgoprudny City, Moscow Region 141700, Russia and Department of Geosciences and Center for Materials by Design, Stony Brook University, Stony Brook, New York 11794, USA and School of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an, Shanxi 710072, People's Republic of China
| | - Qiang Zhu
- Department of Geosciences and Center for Materials by Design, Stony Brook University, Stony Brook, New York 11794, USA
| | - Xiang-Feng Zhou
- Department of Geosciences and Center for Materials by Design, Stony Brook University, Stony Brook, New York 11794, USA
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11
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Ridley MK, Machesky ML, Kubicki JD. Anatase nanoparticle surface reactivity in NaCl media: a CD-MUSIC model interpretation of combined experimental and density functional theory studies. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:8572-8583. [PMID: 23745739 DOI: 10.1021/la4011955] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The effect of particle size on the primary charging behavior of a suite of monodisperse nanometer diameter (4, 20, and 40 nm) anatase samples has been quantitatively examined with macroscopic experimental studies. The experimental results were evaluated using surface complexation modeling, which explicitly incorporated corresponding molecular-scale information from density functional theory (DFT) simulation studies. Potentiometric titrations were completed in NaCl media, at five ionic strengths (from 0.005 to 0.3 m), and over a wide pH range (3-11), at a temperature of 25 °C. From the experimental results, the pH of zero net proton charge (pHznpc) for the 4 and 20 nm diameter samples was 6.42, whereas the pHznpc was 6.22 for the 40 nm sample. The slopes of the net proton charge curves increased with an increase in particle size. Multisite surface complexation and charge distribution (CD) models, with a Basic Stern layer description of the electric double layer, were developed to describe all experimental data. Fits to the experimental data included an inner-sphere Na-bidentate species, an outer-sphere Na-monodentate species, and outer-sphere Cl-monodentate species. DFT simulations found the Na-bidentate species to be the most stable species on the (101) anatase surface (the predominant crystal face). The CD value for the Na-bidentate species was calculated using a bond valence interpretation of the DFT-optimized geometry. The Stern layer capacitance value varied systematically with particle size. The collective experimental and modeling studies show that subtle differences exist in the interface reactivity of nanometer diameter anatase samples. These results should help to further elucidate an understanding of the solid-aqueous solution interface reactivity of nanosized particles.
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Affiliation(s)
- Moira K Ridley
- Department of Geosciences, Texas Tech University, Lubbock, Texas 79409-1053, USA.
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12
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Defect-Driven Restructuring of TiO2 Surface and Modified Reactivity Toward Deposited Gold Atoms. Catalysts 2013. [DOI: 10.3390/catal3010276] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Lu W, Bruner B, Casillas G, Mejía-Rosales S, Farmer PJ, José-Yacamán M. Direct oxygen imaging in titania nanocrystals. NANOTECHNOLOGY 2012; 23:335706. [PMID: 22863879 DOI: 10.1088/0957-4484/23/33/335706] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Recently, rutile nanotwins were synthesized using high temperature organic solvent methods, yielding two kinds of common high-quality rutile twinned nanocrystals, (101) and (301) twins, accompanied by minor rutile nanorods (Lu et al 2012 CrystEngComm 14 3120-4). In this report, the atomic structures of the rutile and anatase nanocrystals are directly resolved with no need for calculation or image simulation using atomic resolution STEM techniques. The locations of the oxygen rows in the rutile twins' boundaries are directly determined from both HAADF images and ABF images. To the best of our knowledge, this is the first time oxygen columns have been distinguished in rutile twin boundaries using HAADF and BF imaging.
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Affiliation(s)
- Weigang Lu
- Department of Chemistry and Biochemistry, Baylor University, Waco, TX 76796, USA
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Yang F, Kundu S, Vidal AB, Graciani J, Ramírez PJ, Senanayake SD, Stacchiola D, Evans J, Liu P, Sanz JF, Rodriguez JA. Determining the Behavior of RuOx Nanoparticles in Mixed-Metal Oxides: Structural and Catalytic Properties of RuO2/TiO2(110) Surfaces. Angew Chem Int Ed Engl 2011. [DOI: 10.1002/ange.201103798] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Yang F, Kundu S, Vidal AB, Graciani J, Ramírez PJ, Senanayake SD, Stacchiola D, Evans J, Liu P, Sanz JF, Rodriguez JA. Determining the Behavior of RuOx Nanoparticles in Mixed-Metal Oxides: Structural and Catalytic Properties of RuO2/TiO2(110) Surfaces. Angew Chem Int Ed Engl 2011; 50:10198-202. [DOI: 10.1002/anie.201103798] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2011] [Revised: 07/04/2011] [Indexed: 11/11/2022]
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16
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Evidence of Coulomb blockade behavior in a quasi-zero-dimensional quantum well on TiO2 surface. Proc Natl Acad Sci U S A 2010; 107:14968-72. [PMID: 20679246 DOI: 10.1073/pnas.1009310107] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Line defects on the surface of rutile TiO(2)(110) form in pairs separated by 1.2 nm creating a quantum well. The well is effectively closed by the presence of two charged structures at both ends separated by a distance in the 10-20 nm range. As expected for quantum confinement a long period oscillatory feature of the local density of states is observed and attributed to the formation of discrete quantum states inside the system. It is at first glance surprising that the lowest energy quantum state of the well can be observed at room temperature. The properties of the quantum state cannot be explained in an independent-electron, band-like theory. Instead, electron-electron correlation must be included to give a satisfactory picture of the spatial distribution of the charge density. Theory predicts charging energies of 1.30 eV and 1.14 eV for quantum well lengths of 14 nm and 16 nm, respectively, in good agreement with a classical calculation and the size dependence of the capacitance. This observation opens up the possibility of experimentally imaging the transition from a Coulomb blockade localized in a zero-dimensional system to an independent-particle or band-like behavior in an extended one-dimensional system.
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17
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Bowker M, Bennett RA. The role of Ti(3+) interstitials in TiO(2)(110) reduction and oxidation. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2009; 21:474224. [PMID: 21832503 DOI: 10.1088/0953-8984/21/47/474224] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Here we describe results which teach us much about the mechanism of the reduction and oxidation of TiO(2)(110) by the application of scanning tunnelling microscopy imaging at high temperatures. Titania reduces at high temperature by thermal oxygen loss to leave localized (i.e. Ti(3+)) and delocalized electrons on the lattice Ti, and a reduced titania interstitial that diffuses into the bulk of the crystal. The interstitial titania can be recalled to the surface by treatment in very low pressures of oxygen, occurring at a significant rate even at 573 K. This re-oxidation occurs by re-growth of titania layers in a Volmer-Weber manner, by a repeating sequence in which in-growth of extra titania within the cross-linked (1 × 2) structure completes the (1 × 1) bulk termination. The next layer then initiates with the nucleation of points and strings which extend to form islands of cross-linked (1 × 2), which once again grow and fill in to reform the (1 × 1). This process continues in a cyclical manner to form many new layers of well-ordered titania. The details of the mechanism and kinetics of the process are considered.
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Affiliation(s)
- Michael Bowker
- Wolfson Nanoscience Laboratory, School of Chemistry, Cardiff University, Cardiff CF10 3AT, UK
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18
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Nolan M, Mulley JS, Bennett RA. Charge transfer in Cr adsorption and reaction at the rutile TiO2(110) surface. Phys Chem Chem Phys 2009; 11:2156-60. [DOI: 10.1039/b819724e] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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19
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Shibata N, Goto A, Choi SY, Mizoguchi T, Findlay SD, Yamamoto T, Ikuhara Y. Direct Imaging of Reconstructed Atoms on TiO
2
(110) Surfaces. Science 2008; 322:570-3. [DOI: 10.1126/science.1165044] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- N. Shibata
- Institute of Engineering Innovation, University of Tokyo, 2-11-16, Yayoi, Bunkyo, Tokyo 113-8656, Japan
- Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency, 4-1-8 Honcho Kawaguchi, Saitama 332-0012, Japan
- Nanostructures Research Laboratory, Japan Fine Ceramic Center, 2-4-1 Mutsuno, Atsuta-ku, Nagoya 456-8587, Japan
- World Premier International Research Center, Advanced Institute for Materials Research, Tohoku University, 2-1-1, Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - A. Goto
- Institute of Engineering Innovation, University of Tokyo, 2-11-16, Yayoi, Bunkyo, Tokyo 113-8656, Japan
- Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency, 4-1-8 Honcho Kawaguchi, Saitama 332-0012, Japan
- Nanostructures Research Laboratory, Japan Fine Ceramic Center, 2-4-1 Mutsuno, Atsuta-ku, Nagoya 456-8587, Japan
- World Premier International Research Center, Advanced Institute for Materials Research, Tohoku University, 2-1-1, Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - S.-Y. Choi
- Institute of Engineering Innovation, University of Tokyo, 2-11-16, Yayoi, Bunkyo, Tokyo 113-8656, Japan
- Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency, 4-1-8 Honcho Kawaguchi, Saitama 332-0012, Japan
- Nanostructures Research Laboratory, Japan Fine Ceramic Center, 2-4-1 Mutsuno, Atsuta-ku, Nagoya 456-8587, Japan
- World Premier International Research Center, Advanced Institute for Materials Research, Tohoku University, 2-1-1, Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - T. Mizoguchi
- Institute of Engineering Innovation, University of Tokyo, 2-11-16, Yayoi, Bunkyo, Tokyo 113-8656, Japan
- Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency, 4-1-8 Honcho Kawaguchi, Saitama 332-0012, Japan
- Nanostructures Research Laboratory, Japan Fine Ceramic Center, 2-4-1 Mutsuno, Atsuta-ku, Nagoya 456-8587, Japan
- World Premier International Research Center, Advanced Institute for Materials Research, Tohoku University, 2-1-1, Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - S. D. Findlay
- Institute of Engineering Innovation, University of Tokyo, 2-11-16, Yayoi, Bunkyo, Tokyo 113-8656, Japan
- Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency, 4-1-8 Honcho Kawaguchi, Saitama 332-0012, Japan
- Nanostructures Research Laboratory, Japan Fine Ceramic Center, 2-4-1 Mutsuno, Atsuta-ku, Nagoya 456-8587, Japan
- World Premier International Research Center, Advanced Institute for Materials Research, Tohoku University, 2-1-1, Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - T. Yamamoto
- Institute of Engineering Innovation, University of Tokyo, 2-11-16, Yayoi, Bunkyo, Tokyo 113-8656, Japan
- Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency, 4-1-8 Honcho Kawaguchi, Saitama 332-0012, Japan
- Nanostructures Research Laboratory, Japan Fine Ceramic Center, 2-4-1 Mutsuno, Atsuta-ku, Nagoya 456-8587, Japan
- World Premier International Research Center, Advanced Institute for Materials Research, Tohoku University, 2-1-1, Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Y. Ikuhara
- Institute of Engineering Innovation, University of Tokyo, 2-11-16, Yayoi, Bunkyo, Tokyo 113-8656, Japan
- Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency, 4-1-8 Honcho Kawaguchi, Saitama 332-0012, Japan
- Nanostructures Research Laboratory, Japan Fine Ceramic Center, 2-4-1 Mutsuno, Atsuta-ku, Nagoya 456-8587, Japan
- World Premier International Research Center, Advanced Institute for Materials Research, Tohoku University, 2-1-1, Katahira, Aoba-ku, Sendai 980-8577, Japan
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Warschkow O, Wang Y, Subramanian A, Asta M, Marks LD. Structure and local-equilibrium thermodynamics of the c(2x2) reconstruction of rutile TiO2 (100). PHYSICAL REVIEW LETTERS 2008; 100:086102. [PMID: 18352638 DOI: 10.1103/physrevlett.100.086102] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2007] [Indexed: 05/26/2023]
Abstract
We resolve the structure of a c(2x2) reconstruction of the rutile TiO2 (100) surface using a combination of transmission electron diffraction, direct methods analysis, and density functional theory. The surface structure contains an ordered array of subsurface oxygen vacancies and is in local thermodynamic equilibrium with bulk TiO2, but not the with oxygen gas-phase environment. The transition into a bulklike (1x1) reconstruction offers insights into the time-dependent local thermodynamics of TiO2 surface reconstruction under global nonequilibrium conditions.
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Affiliation(s)
- O Warschkow
- School of Physics, The University of Sydney, Sydney, NSW 2006, Australia
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21
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Lun Pang C, Lindsay R, Thornton G. Chemical reactions on rutile TiO2(110). Chem Soc Rev 2008; 37:2328-53. [DOI: 10.1039/b719085a] [Citation(s) in RCA: 435] [Impact Index Per Article: 27.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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22
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Bondarchuk O, Lyubinetsky I. Preparation of TiO2(110)-(1x1) surface via UHV cleavage: an scanning tunneling microscopy study. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2007; 78:113907. [PMID: 18052488 DOI: 10.1063/1.2814160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
TiO2(110) surface was successfully prepared in situ by UHV cleaving of a commercial TiO2 crystal. Scanning tunneling microscopy (STM) imaging revealed atomically flat more than 1 mum wide terraces with (110) orientation separated by steps running in [001] direction, with very low kink density. Atomically resolved STM images show periodicity in the [001] and [110] directions with the unit cell parameters measured to approximately 3 and 6.5 A, respectively, which are closed to the expected values of bulk terminated (1 x 1) surface.
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Affiliation(s)
- O Bondarchuk
- Center for Materials Chemistry, Texas Materials Institute, University of Texas, Austin, Texas 78712, USA.
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23
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Abstract
Surface structures of rutile TiO(2) (011) are determined by a combination of noncontact atomic force microscopy (NC-AFM), scanning tunneling microscopy (STM), and density functional calculations. The surface exhibits rowlike (n x 1) structures running along the [01] direction. Microfaceting missing-row structural models can explain the experimental results very well. Calculated images for NC-AFM and STM are in good agreement with the experimental results. A decrease of the density of dangling bonds stabilizes the surface energy, which results in the microfaceting missing-row reconstructions.
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Affiliation(s)
- Toshitaka Kubo
- National Institute of Advanced Industrial Science and Technology, Tsukuba Central 5-2, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan.
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Bennett RA, McCavish ND, Basham M, Dhanak VR, Newton MA. Structure of adsorbed organometallic rhodium: model single atom catalysts. PHYSICAL REVIEW LETTERS 2007; 98:056102. [PMID: 17358876 DOI: 10.1103/physrevlett.98.056102] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2006] [Indexed: 05/14/2023]
Abstract
We have determined the structure of a complex rhodium carbonyl chloride [Rh(CO)2Cl] molecule adsorbed on the TiO2(110) surface by the normal incidence x-ray standing wave technique. The data show that the technique is applicable to reducible oxide systems and that the dominant adsorbed species is undissociated with Rh binding atop bridging oxygen and to the Cl found close to the fivefold coordinated Ti ions in the surface. A minority geminal dicarbonyl species, where Rh-Cl bond scission has occurred, is found bridging the bridging oxygen ions forming a high-symmetry site.
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Affiliation(s)
- R A Bennett
- Department of Physics, University of Reading, Whiteknights, Reading, RG6 6AF, United Kingdom
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