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Xia Z, Zhu X, Chen X, Zhou Y, Luo Q, Yang J. Unveiling the Composition-Dependent Catalytic Mechanism of Pt-Ni Alloys for Oxygen Reduction: A First-Principles Study. J Phys Chem Lett 2024:9566-9574. [PMID: 39265186 DOI: 10.1021/acs.jpclett.4c02164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/14/2024]
Abstract
Unveiling the composition-dependent catalytic mechanism of Pt-based alloy cathodes for the oxygen reduction reaction (ORR) helps improve the proton exchange membrane fuel cells. Using density functional theory calculations, this study investigates the ORR catalytic performance of the Pt-Ni system with various compositions (1.00, ∼0.99, 0.75, 0.50, 0.25, ∼0.01, and 0.00). The ordered solid solution PtNi3(111) system shows activity comparable to Pt(111) and is cost-effective. The Ni1/Pt(111) system, featuring a single Ni atom on the Pt(111) surface as a surface single-atom alloy (SSAA), demonstrates the highest activity with an overpotential of only 0.28, which could be further reduced to 0.21 V by decreasing the surface Ni concentration to 1/16 monolayer coverage. The predicted high activity of Ni1/Pt(111) is confirmed when considering factors such as the implicit solution environment, constant potential conditions, and protonation capability. Moreover, surface-adsorbed oxygen species driven by reaction conditions stabilize these single Ni atoms of Ni1/Pt(111) by preventing segregation and dissolution processes, thereby exhibiting a dual functionality. This study reveals the composition dependence of Pt-based alloys and highlights the stability mechanisms of SSAA catalysts during the ORR.
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Affiliation(s)
- Zhiyuan Xia
- Institutes of Physical Science and Information Technology, Anhui University, Hefei, Anhui 230601, China
| | - Xiangyu Zhu
- Institutes of Physical Science and Information Technology, Anhui University, Hefei, Anhui 230601, China
| | - Xing Chen
- Institutes of Physical Science and Information Technology, Anhui University, Hefei, Anhui 230601, China
| | - Yanan Zhou
- School of Material Science and Chemical Engineering, Ningbo University, Ningbo 315211, China
| | - Qiquan Luo
- Institutes of Physical Science and Information Technology, Anhui University, Hefei, Anhui 230601, China
| | - Jinlong Yang
- Department of Chemical Physics, Key Laboratory of Precision and Intelligent Chemistry, Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China
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2
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150 years of oxygen chemistry. NATURE COMPUTATIONAL SCIENCE 2024; 4:461. [PMID: 39079977 DOI: 10.1038/s43588-024-00670-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/03/2024]
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3
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Rice PS, Lee G, Schwartz B, Autrey T, Ginovska B. Leveraging Curvature on N-Doped Carbon Materials for Hydrogen Storage. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2310162. [PMID: 38221703 DOI: 10.1002/smll.202310162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 12/25/2023] [Indexed: 01/16/2024]
Abstract
Carbon sorbent materials have shown great promise for solid-state hydrogen (H2) storage. Modification of these materials with nitrogen (N) dopants has been undertaken to develop materials that can store H2 at ambient temperatures. In this work density functional theory (DFT) calculations are used to systematically probe the influence of curvature on the stability and activity of undoped and N-doped carbon materials toward H binding. Specifically, four models of carbon materials are used: graphene, [5,5] carbon nanotube, [5,5] D5d-C120, and C60, to extract and correlate the thermodynamic properties of active sites with varying degrees of sp2 hybridization (curvature). From the calculations and analysis, it is found that graphitic N-doping is thermodynamically favored on more pyramidal sites with increased curvature. In contrast, it is found that the hydrogen binding energy is weakly affected by curvature and is dominated by electronic effects induced by N-doping. These findings highlight the importance of modulating the heteroatom doping configuration and the lattice topology when developing materials for H2 storage.
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Affiliation(s)
- Peter S Rice
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, WA, 99352, USA
| | - Gabriel Lee
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, WA, 99352, USA
| | - Brayden Schwartz
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, WA, 99352, USA
| | - Tom Autrey
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, WA, 99352, USA
| | - Bojana Ginovska
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, WA, 99352, USA
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4
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Qiao Z, Jiang R, Xu H, Cao D, Zeng XC. A General Descriptor for Single-Atom Catalysts with Axial Ligands. Angew Chem Int Ed Engl 2024:e202407812. [PMID: 38771728 DOI: 10.1002/anie.202407812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2024] [Revised: 05/16/2024] [Accepted: 05/21/2024] [Indexed: 05/23/2024]
Abstract
Decoration of an axial coordination ligand (ACL) on the active metal site is a highly effective and versatile strategy to tune activity of single-atom catalysts (SACs). However, the regulation mechanism of ACLs on SACs is still incompletely known. Herein, we investigate diversified combinations of ACL-SACs, including all 3d-5d transition metals and ten prototype ACLs. We identify that ACLs can weaken the adsorption capability of the metal atom (M) by raising the bonding energy levels of the M-O bond while enhancing dispersity of the d orbital of M. Through examination of various local configurations and intrinsic parameters of ACL-SACs, a general structure descriptor σ is constructed to quantify the structure-activity relationship of ACL-SACs which solely based on a few key intrinsic features. Importantly, we also identified the axial ligand descriptor σACL, as a part of σ, which can serve as a potential descriptor to determine the rate-limiting steps (RLS) of ACL-SACs in experiment. And we predicted several ACL-SACs, namely, CrN4-, FeN4-, CoN4-, RuN4-, RhN4-, OsN4-, IrN4- and PtN4-ACLs, that entail markedly higher activities than the benchmark catalysts of Pt and IrO2 for oxygen reduction reaction and oxygen evolution reaction, respectively, thereby supporting that the general descriptor σ can provide a simple and cost-effective method to assess efficient electrocatalysts.
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Affiliation(s)
- Zelong Qiao
- State Key Laboratory of Organic-Inorganic Composites, Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Run Jiang
- State Key Laboratory of Organic-Inorganic Composites, Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Haoxiang Xu
- State Key Laboratory of Organic-Inorganic Composites, Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Dapeng Cao
- State Key Laboratory of Organic-Inorganic Composites, Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Xiao Cheng Zeng
- Department of Materials Science & Engineering, City University of Hong Kong, Kowloon, 99977, Hong Kong
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5
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Khamaru K, Pal U, Shee S, Lo R, Seal K, Ghosh P, Maiti NC, Banerji B. Metal-Free Activation of Molecular Oxygen by Quaternary Ammonium-Based Ionic Liquid: A Detail Mechanistic Study. J Am Chem Soc 2024; 146:6912-6925. [PMID: 38421821 DOI: 10.1021/jacs.3c14366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2024]
Abstract
Most oxidation processes in common organic synthesis and chemical biology require transition metal catalysts or metalloenzymes. Herein, we report a detailed mechanistic study of a metal-free oxygen (O2) activation protocol on benzylamine/alcohols using simple quaternary alkylammonium-based ionic liquids to produce products such as amide, aldehyde, imine, and in some cases, even aromatized products. NMR and various control experiments established the product formation and reaction mechanism, which involved the conversion of molecular oxygen into a hydroperoxyl radical via a proton-coupled electron transfer process. Detection of hydrogen peroxide in the reaction medium using colorimetric analysis supported the proposed mechanism of oxygen activation. Furthermore, first-principles calculations using density functional theory (DFT) revealed that reaction coordinates and transition state spin densities have a unique spin conversion of triplet oxygen leading to formation of singlet products via a minimum energy crossing point. In addition to DFT, domain-based local pair natural orbital coupled cluster, (DLPNO-CCSD(T)), and complete active space self-consistent field, CASSCF(20,14) methods complemented the above findings. Partial density of states analysis showed stabilization of π* orbital of oxygen in the presence of ionic liquid, making it susceptible to hydrogen abstraction in a mild, metal-free condition. Inductively coupled plasma atomic emission spectroscopic (ICP-AES) analysis of reactant and ionic liquids clearly showed the absence of any significant transition metal contamination. The current results described the origin of O2 activation within the context of molecular orbital (MO) theory and opened up a new avenue for the use of ionic liquids as inexpensive, multifunctional and high-performance alternative to metal-based catalysts for O2 activation.
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Affiliation(s)
| | - Uttam Pal
- CSIR-Indian Institute of Chemical Biology, Kolkata 700032, India
| | - Subhankar Shee
- CSIR-Indian Institute of Chemical Biology, Kolkata 700032, India
| | - Rabindranath Lo
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, v.v.i., Flemingovo nám. 2, 16610 Prague 6, Czech Republic
| | - Kaushik Seal
- CSIR-Indian Institute of Chemical Biology, Kolkata 700032, India
| | - Prasanta Ghosh
- Department of Chemistry, Ramakrishna Mission Residential College (Autonomous), Narendrapur, Kolkata 700103, India
| | - Nakul Chandra Maiti
- CSIR-Indian Institute of Chemical Biology, Kolkata 700032, India
- Academy of Scientific and Innovative Research (AcSIR), Kolkata 700032, India
| | - Biswadip Banerji
- CSIR-Indian Institute of Chemical Biology, Kolkata 700032, India
- Academy of Scientific and Innovative Research (AcSIR), Kolkata 700032, India
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Zhang P, Chen HC, Zhu H, Chen K, Li T, Zhao Y, Li J, Hu R, Huang S, Zhu W, Liu Y, Pan Y. Inter-site structural heterogeneity induction of single atom Fe catalysts for robust oxygen reduction. Nat Commun 2024; 15:2062. [PMID: 38453927 PMCID: PMC10920901 DOI: 10.1038/s41467-024-46389-3] [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: 09/19/2023] [Accepted: 02/23/2024] [Indexed: 03/09/2024] Open
Abstract
Metal-nitrogen-carbon catalysts with hierarchically dispersed porosity are deemed as efficient geometry for oxygen reduction reaction (ORR). However, catalytic performance determined by individual and interacting sites originating from structural heterogeneity is particularly elusive and yet remains to be understood. Here, an efficient hierarchically porous Fe single atom catalyst (Fe SAs-HP) is prepared with Fe atoms densely resided at micropores and mesopores. Fe SAs-HP exhibits robust ORR performance with half-wave potential of 0.94 V and turnover frequency of 5.99 e-1s-1site-1 at 0.80 V. Theoretical simulations unravel a structural heterogeneity induced optimization, where mesoporous Fe-N4 acts as real active centers as a result of long-range electron regulation by adjacent microporous sites, facilitating O2 activation and desorption of key intermediate *OH. Multilevel operando characterization results identify active Fe sites undergo a dynamic evolution from basic Fe-N4 to active Fe-N3 under working conditions. Our findings reveal the structural origin of enhanced intrinsic activity for hierarchically porous Fe-N4 sites.
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Affiliation(s)
- Peng Zhang
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao, 266580, China
| | - Hsiao-Chien Chen
- Center for Reliability Science and Technologies, Chang Gung University, Taoyuan, 33302, Taiwan
- Kidney Research Center, Department of Nephrology, Chang Gung Memorial Hospital, Linkou, Taoyuan, 33305, Taiwan
| | - Houyu Zhu
- School of Materials Science and Engineering, China University of Petroleum (East China), Qingdao, 266580, China
| | - Kuo Chen
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao, 266580, China
| | - Tuya Li
- School of Materials Science and Engineering, China University of Petroleum (East China), Qingdao, 266580, China
| | - Yilin Zhao
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao, 266580, China
| | - Jiaye Li
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao, 266580, China
| | - Ruanbo Hu
- State Key Lab of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Siying Huang
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao, 266580, China
| | - Wei Zhu
- State Key Lab of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Yunqi Liu
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao, 266580, China.
| | - Yuan Pan
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao, 266580, China.
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7
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Zhang Z, Li J, Wang YG. Modeling Interfacial Dynamics on Single Atom Electrocatalysts: Explicit Solvation and Potential Dependence. Acc Chem Res 2024; 57:198-207. [PMID: 38166366 DOI: 10.1021/acs.accounts.3c00589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2024]
Abstract
ConspectusSingle atom electrocatalysts, with noble metal-free composition, maximal atom efficiency, and exceptional reactivity toward various energy and environmental applications, have become a research hot spot in the recent decade. Their simplicity and the isolated nature of the atomic structure of their active site have also made them an ideal model catalyst system for studying reaction mechanisms and activity trends. However, the state of the single atom active sites during electrochemical reactions may not be as simple as is usually assumed. To the contrary, the single atom electrocatalysts have been reported to be under greater influence from interfacial dynamics, with solvent and electrolyte ions perpetually interacting with the electrified active center under an applied electrode potential. These complexities render the activity trends and reaction mechanisms derived from simplistic models dubious.In this Account, with a few popular single atom electrocatalysis systems, we show how the change in electrochemical potential induces nontrivial variation in the free energy profile of elemental electrochemical reaction steps, demonstrate how the active centers with different electronic structure features can induce different solvation structures at the interface even for the same reaction intermediate of the simplest electrochemical reaction, and discuss the implication of the complexities on the kinetics and thermodynamics of the reaction system to better address the activity and selectivity trends. We also venture into more intriguing interfacial phenomena, such as alternative reaction pathways and intermediates that are favored and stabilized by solvation and polarization effects, long-range interfacial dynamics across the region far beyond the contact layer, and the dynamic activation or deactivation of single atom sites under operation conditions. We show the necessity of including realistic aspects (explicit solvent, electrolyte, and electrode potential) into the model to correctly capture the physics and chemistry at the electrochemical interface and to understand the reaction mechanisms and reactivity trends. We also demonstrate how the popular simplistic design principles fail and how they can be revised by including the kinetics and interfacial factors in the model. All of these rich dynamics and chemistry would remain hidden or overlooked otherwise. We believe that the complexity at an electrochemical interface is not a curse but a blessing in that it enables deeper understanding and finer control of the potential-dependent free energy landscape of electrochemical reactions, which opens up new dimensions for further design and optimization of single atom electrocatalysts and beyond. Limitations of current methods and challenges faced by the theoretical and experimental communities are discussed, along with the possible solutions awaiting development in the future.
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Affiliation(s)
- Zisheng Zhang
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Jun Li
- Department of Chemistry and Key Laboratory of Organic Optoelectronics & Molecular Engineering of Ministry of Education, Tsinghua University, Beijing 100084, China
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Liu H, Sun F, Yang L, Chen M, Wang H. Gaining insight into the impact of electronic property and interface electrostatic field on ORR kinetics in alloy engineering via theoretical prognostication and experimental validation. J Colloid Interface Sci 2023; 652:890-900. [PMID: 37634362 DOI: 10.1016/j.jcis.2023.08.125] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 07/27/2023] [Accepted: 08/20/2023] [Indexed: 08/29/2023]
Abstract
Alloy engineering has been utilized as a potent strategy to modulate the oxygen reduction reaction (ORR) activity. However, the regulatory mechanism underpinning the ORR kinetics by means of alloy engineering is still shrouded in ambiguity. This work places emphasis on the kinetics of the ORR concerning Pt3M (M = Cr, Co, Cu, Pd, Sn, and Ir) catalysts, and integrates theoretical prognostication and experimental validation to illuminate the fundamental principles of alloy engineering. The ORR kinetic activity, as prognosticated by theory, shows significant agreement with experimental results, provided that the rate-determining step (RDS) accounts for a dominant role in the potential-independent kinetic mechanism. In essence, alloy engineering manipulates electronic properties through electron transfer to modulate intermediate adsorption and adjusts the interface electric field (Efield) to regulate hydrogen atom transport, ultimately influencing kinetics. The Efield holds greater significance in ORR kinetics compared to the intermediate adsorption (EadsO), the corresponding degrees of correlation with free energy barriers (Ea) of RDS are -0.89, and 0.75, respectively. This work highlights the nature of alloy engineering for ORR kinetics modulation and assists in the design of efficient catalysts.
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Affiliation(s)
- Haijun Liu
- Harbin Institute of Technology, Harbin 150001, China; Department of Mechanical and Energy Engineering, Southern University of Science and Technology, Shenzhen 518055, China; Key Laboratory of Energy Conversion and Storage Technologies (Southern University of Science and Technology), Ministry of Education, Shenzhen 518055, China
| | - Fengman Sun
- Harbin Institute of Technology, Harbin 150001, China; Department of Mechanical and Energy Engineering, Southern University of Science and Technology, Shenzhen 518055, China; Key Laboratory of Energy Conversion and Storage Technologies (Southern University of Science and Technology), Ministry of Education, Shenzhen 518055, China
| | - Lin Yang
- Department of Mechanical and Energy Engineering, Southern University of Science and Technology, Shenzhen 518055, China; Key Laboratory of Energy Conversion and Storage Technologies (Southern University of Science and Technology), Ministry of Education, Shenzhen 518055, China; School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang 453007, China
| | - Ming Chen
- Department of Mechanical and Energy Engineering, Southern University of Science and Technology, Shenzhen 518055, China; Key Laboratory of Energy Conversion and Storage Technologies (Southern University of Science and Technology), Ministry of Education, Shenzhen 518055, China.
| | - Haijiang Wang
- Department of Mechanical and Energy Engineering, Southern University of Science and Technology, Shenzhen 518055, China; Key Laboratory of Energy Conversion and Storage Technologies (Southern University of Science and Technology), Ministry of Education, Shenzhen 518055, China.
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9
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Zhao CX, Liu X, Liu JN, Wang J, Wan X, Wang C, Li XY, Shui J, Song L, Peng HJ, Li BQ, Zhang Q. Molecular Recognition Regulates Coordination Structure of Single-Atom Sites. Angew Chem Int Ed Engl 2023; 62:e202313028. [PMID: 37851474 DOI: 10.1002/anie.202313028] [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: 09/03/2023] [Revised: 10/04/2023] [Accepted: 10/11/2023] [Indexed: 10/19/2023]
Abstract
Coordination engineering for single-atom sites has drawn increasing attention, yet its chemical synthesis remains a tough issue, especially for tailorable coordination structures. Herein, a molecular recognition strategy is proposed to fabricate single-atom sites with regulable local coordination structures. Specifically, a heteroatom-containing ligand serves as the guest molecule to induce coordination interaction with the metal-containing host, precisely settling the heteroatoms into the local structure of single-atom sites. As a proof of concept, thiophene is selected as the guest molecule, and sulfur atoms are successfully introduced into the local coordination structure of iron single-atom sites. Ultrahigh oxygen reduction electrocatalytic activity is achieved with a half-wave potential of 0.93 V versus reversible hydrogen electrode. Furthermore, the strategy possesses excellent universality towards diversified types of single-atom sites. This work makes breakthroughs in the fabrication of single-atom sites and affords new opportunities in structural regulation at the atomic level.
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Affiliation(s)
- Chang-Xin Zhao
- Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology, Department of Chemical Engineering, Tsinghua University, Beijing, 100084, China
| | - Xinyan Liu
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu, 611731, Sichuan, China
| | - Jia-Ning Liu
- Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology, Department of Chemical Engineering, Tsinghua University, Beijing, 100084, China
| | - Juan Wang
- Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing, 100081, China
- School of Materials Science and Engineering, Beijing Institute of Technology, Beijing, 100081, China
| | - Xin Wan
- School of Materials Science and Engineering, Beihang University, Beijing, 100191, China
| | - Changda Wang
- National Synchrotron Radiation Laboratory, CAS Center for Excellence in Nanoscience, University of Science and Technology of China, Hefei, 230029, Anhui, China
| | - Xi-Yao Li
- Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology, Department of Chemical Engineering, Tsinghua University, Beijing, 100084, China
| | - Jianglan Shui
- School of Materials Science and Engineering, Beihang University, Beijing, 100191, China
| | - Li Song
- National Synchrotron Radiation Laboratory, CAS Center for Excellence in Nanoscience, University of Science and Technology of China, Hefei, 230029, Anhui, China
| | - Hong-Jie Peng
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu, 611731, Sichuan, China
| | - Bo-Quan Li
- Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing, 100081, China
- School of Materials Science and Engineering, Beijing Institute of Technology, Beijing, 100081, China
| | - Qiang Zhang
- Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology, Department of Chemical Engineering, Tsinghua University, Beijing, 100084, China
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10
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Yu S, Levell Z, Jiang Z, Zhao X, Liu Y. What Is the Rate-Limiting Step of Oxygen Reduction Reaction on Fe-N-C Catalysts? J Am Chem Soc 2023; 145:25352-25356. [PMID: 37955970 DOI: 10.1021/jacs.3c09193] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Oxygen reduction reaction (ORR) is essential to various renewable energy technologies. An important catalyst for ORR is single iron atoms embedded in nitrogen-doped graphene (Fe-N-C). However, the rate-limiting step of the ORR on Fe-N-C is unknown, significantly impeding understanding and improvement. Here, we report the activation energies of all of the steps, calculated by ab initio molecular dynamics simulations under constant electrode potential. In contrast to the common belief that a hydrogenation step limits the reaction rate, we find that the rate-limiting step is oxygen molecule replacing adsorbed water on Fe. This occurs through concerted motion of H2O desorption and O2 adsorption, without leaving the site bare. Interestingly, despite being an apparent "thermal" process that is often considered to be potential-independent, the barrier reduces with the electrode potential. This can be explained by stronger Fe-O2 binding and weaker Fe-H2O binding at a lower potential, due to O2 gaining electrons and H2O donating electrons to the catalyst. Our study offers new insights into the ORR on Fe-N-C and highlights the importance of kinetic studies in heterogeneous electrochemistry.
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Affiliation(s)
- Saerom Yu
- Texas Materials Institute and Department of Mechanical Engineering, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Zachary Levell
- Texas Materials Institute and Department of Mechanical Engineering, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Zhou Jiang
- Texas Materials Institute and Department of Mechanical Engineering, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Xunhua Zhao
- Texas Materials Institute and Department of Mechanical Engineering, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Yuanyue Liu
- Texas Materials Institute and Department of Mechanical Engineering, The University of Texas at Austin, Austin, Texas 78712, United States
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11
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Liu JC, Luo F, Li J. Electrochemical Potential-Driven Shift of Frontier Orbitals in M-N-C Single-Atom Catalysts Leading to Inverted Adsorption Energies. J Am Chem Soc 2023; 145:25264-25273. [PMID: 37939166 DOI: 10.1021/jacs.3c08697] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2023]
Abstract
Electronic structure is essential to understanding the catalytic mechanism of metal single-atom catalysts (SACs), especially under electrochemical conditions. This study delves into the nuanced modulation of "frontier orbitals" in SACs on nitrogen-doped graphene (N-C) substrates by electrochemical potentials. We observe shifts in Fermi level and changes of d-orbital occupation with alterations in electrochemical potentials, emphasizing a synergy between the discretized atomic orbitals of metals and the continuous bands of the N-C based environment. Using O2 and CO2 as model adsorbates, we highlight the direct consequences of these shifts on adsorption energies, unveiling an intriguing inversion of adsorption energies on Co/N-C SAC under negative electrochemical potentials. Such insights are attributed to the role of the dxz and dz2 orbitals, pivotal for stabilizing the π* orbitals of O2. Through this exploration, our work offers insights on the interplay between electronic structures and adsorption behaviors in SACs, paving the way for enhanced catalyst design strategies in electrochemical processes.
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Affiliation(s)
- Jin-Cheng Liu
- Center for Rare Earth and Inorganic Functional Materials, School of Materials Science and Engineering & National Institute for Advanced Materials, Nankai University, Tianjin 300350, China
| | - Feng Luo
- Center for Rare Earth and Inorganic Functional Materials, School of Materials Science and Engineering & National Institute for Advanced Materials, Nankai University, Tianjin 300350, China
| | - Jun Li
- Department of Chemistry and Engineering Research Center of Advanced Rare-Earth Materials of Ministry of Education, Tsinghua University, Beijing 100084, China
- Department of Chemistry and Guangdong Provincial Key Laboratory of Catalytic Chemistry, Southern University of Science and Technology, Shenzhen 518055, China
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12
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Han Y, Ye K, Huang Y, Wu Z, Hu P, Zhang G. Leveraging Interlayer Interaction in M-N-C Catalysts for Enhanced Activity in Oxygen Reduction Reactions. J Phys Chem Lett 2023; 14:9900-9908. [PMID: 37903101 DOI: 10.1021/acs.jpclett.3c02385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2023]
Abstract
Atomically dispersed metal-nitrogen-carbon (M-N-C) materials are deemed promising catalysts for the oxygen reduction reaction (ORR) in fuel cells. Yet the multilayer nature of M-N-C has been largely neglected in computational analysis. To bridge the gap, we conducted a first-principles investigation using bilayer M-N-C models (TMNx/G-TMNy/G, TM = Mn, Fe, Co, Ni, Cu, G = graphene, x, y = 3 or 4), where the TMs on the top serves as the active center. While in-plane TMN4 at the bottom has a minimal impact on the ORR, out-of-plane TMN3 substantially influences the adsorption free energy of OH through a strong interlayer bonding interaction. By leveraging interlayer interactions, we appreciably lowered the overpotential of selected TMN4 (TM = Co, Ni, Cu) and achieved a minimum of 0.40 V on CoN4/G-CuN3/G. Constant potential calculations revealed weak dependence of OH binding energy on external voltage and obtained results comparable to constant charge calculation. This study provided new physical insight into modulating naturally occurring multilayer M-N-C catalysts.
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Affiliation(s)
- Yulan Han
- School of Chemistry and Chemical Engineering, Queen's University Belfast, Belfast BT9 5AG, U.K
- Hefei National Research Center for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui 230026 China
| | - Ke Ye
- Hefei National Research Center for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui 230026 China
| | - Yang Huang
- School of Chemistry and Chemical Engineering, Queen's University Belfast, Belfast BT9 5AG, U.K
| | - Ziye Wu
- School of Information, Guizhou University of Finance and Economics, Guiyang 550025, China
| | - P Hu
- School of Chemistry and Chemical Engineering, Queen's University Belfast, Belfast BT9 5AG, U.K
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Guozhen Zhang
- Hefei National Research Center for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui 230026 China
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13
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Hu X, Su NQ. Targeted Spin-State Regulation to Boost Oxygen Reduction Reaction. J Phys Chem Lett 2023; 14:9872-9882. [PMID: 37902469 DOI: 10.1021/acs.jpclett.3c02412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2023]
Abstract
Catalytic reactions are known to be significantly affected by spin states and their variations during reaction processes, yet the mechanisms behind them remain not fully understood, thus preventing the rational optimization of catalysis. Here, we explore the relationship between the spin states of active sites and their catalytic performance, taking the oxygen reduction reaction as an example. We demonstrate that the catalytic performance is spin-state-dependent and can be improved by adjusting spin states during the catalytic process. To this end, we further investigate the possibility of altering the spin states of transition metals through the application of external fields, such as adsorbed species. By studying the influence of the strength of adsorbed ligands on spin states and its impact on catalytic performance, our results show that optimal catalytic performance is achieved when the strength of the external field is neither too strong nor too weak, forming a volcano-like relationship between the catalytic performance and the external field strength. Our findings can have far-reaching implications for the rational design of high-performance catalysis.
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Affiliation(s)
- Xiuli Hu
- Department of Chemistry, Frontiers Science Center for New Organic Matter, State Key Laboratory of Advanced Chemical Power Sources, Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Nankai University, Tianjin 300071, China
| | - Neil Qiang Su
- Department of Chemistry, Frontiers Science Center for New Organic Matter, State Key Laboratory of Advanced Chemical Power Sources, Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Nankai University, Tianjin 300071, China
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14
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Wang Y, Meng S, Liu M. Collective Behavior of Single-Atom Catalysts: A Synergistic Effect between Strain and Site Configuration. J Phys Chem Lett 2023; 14:9918-9925. [PMID: 37903129 DOI: 10.1021/acs.jpclett.3c02530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2023]
Abstract
Fe single-atom catalysts on N-doped graphene (Fe-NC) exhibit good and variable catalytic activity linked to the active site density and configuration. Here, we comprehensively investigate the Fe-NC catalysts under various strained states and site densities to address the interplay between the active site density, local strain, site geometry, and oxygen evolution reaction (OER) activity. It is found that the active site density is closely associated with in-plane strain, which can be tuned by popping up Fe single atoms from the graphene film and, thereby, modulating the OER catalytic activity. Further analysis indicates that there exist three orientations of the FeN4 active site, each introducing specific anisotropic strain. As a result, the in-plane strain correlates with both the orientation and density of the active site, ultimately influencing catalytic activity. Our findings demonstrate the synergistic effects of multiple factors in single-atom catalysts, providing new insights into the rational design and fine tuning single-atom catalysts via collective interactions.
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Affiliation(s)
- Yanan Wang
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, People's Republic of China
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Sheng Meng
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, People's Republic of China
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Miao Liu
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, People's Republic of China
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
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15
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Zhang P, Chen K, Li J, Wang M, Li M, Liu Y, Pan Y. Bifunctional Single Atom Catalysts for Rechargeable Zinc-Air Batteries: From Dynamic Mechanism to Rational Design. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2303243. [PMID: 37283478 DOI: 10.1002/adma.202303243] [Citation(s) in RCA: 23] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 05/21/2023] [Indexed: 06/08/2023]
Abstract
Ever-growing demands for rechargeable zinc-air batteries (ZABs) call for efficient bifunctional electrocatalysts. Among various electrocatalysts, single atom catalysts (SACs) have received increasing attention due to the merits of high atom utilization, structural tunability, and remarkable activity. Rational design of bifunctional SACs relies heavily on an in-depth understanding of reaction mechanisms, especially dynamic evolution under electrochemical conditions. This requires a systematic study in dynamic mechanisms to replace current trial and error modes. Herein, fundamental understanding of dynamic oxygen reduction reaction and oxygen evolution reaction mechanisms for SACs is first presented combining in situ and/or operando characterizations and theoretical calculations. By highlighting structure-performance relationships, rational regulation strategies are particularly proposed to facilitate the design of efficient bifunctional SACs. Furthermore, future perspectives and challenges are discussed. This review provides a thorough understanding of dynamic mechanisms and regulation strategies for bifunctional SACs, which are expected to pave the avenue for exploring optimum single atom bifunctional oxygen catalysts and effective ZABs.
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Affiliation(s)
- Peng Zhang
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao, 266580, China
| | - Kuo Chen
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao, 266580, China
| | - Jiaye Li
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao, 266580, China
| | - Minmin Wang
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao, 266580, China
| | - Min Li
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao, 266580, China
| | - Yunqi Liu
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao, 266580, China
| | - Yuan Pan
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao, 266580, China
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16
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Liu Y, Liu X, Gong J, Li Y, Yuan X, Zhang G, Wu Q, Li Z. Electronic Structure Modulation of Fe-N 4-C for Oxygen Evolution Reaction via Transition Metal Dopants and Axial Ligands. ACS APPLIED MATERIALS & INTERFACES 2023; 15:40614-40622. [PMID: 37586076 DOI: 10.1021/acsami.3c08220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/18/2023]
Abstract
The popular single-atom catalyst (SAC) Fe-N4 is generally believed to be an excellent oxygen reduction reaction (ORR) electrocatalyst, which is less active in the oxygen evolution reaction (OER). Herein, FeM-N6 configuration catalysts (M = Fe, Co, Ni, Cu, Ag, and Au) were constructed for the oxygen evolution reaction by embedding M dopants on Fe-N4 systems based on the density functional theory. The electronic structure analysis reveals that the Fe-M metal interactions play dominant roles in regulating the d orbital distributions of Fe sites, which in turn alter the catalytic OER performance. Subsequent thermodynamic results indicate that the potential-determining step (PDS) for all catalysts is the formation of OOH*, which exhibits a tendency of decreased overpotentials with enhanced metal interactions. Apart from these, the effects of axial ligands on the OER activity of the catalysts in practical conditions were considered. Generally, most of the axial ligands are found to be thermodynamically favorable for the OER process. Interestingly, a competitive relationship of the electrons from the d orbital of Fe sites was found between the axial ligand and the adsorbed intermediate species during the reaction, which raises the energy barrier for OH* to O* conversion and can even alter the PDS in certain cases. The present work sheds new light on the design of future high-performance OER catalysts.
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Affiliation(s)
- Yangfan Liu
- School of Materials Science and Engineering, Central South University, 410083 Changsha, P. R. China
| | - Xinghan Liu
- Hunan Key Laboratory of Nanophotonics and Devices, School of Physics and Electronics, Central South University, 410083 Changsha, P. R. China
| | - Jun Gong
- School of Mechanical Engineering, Hunan University of Science and Technology, 411201 Xiangtan, P. R. China
- Department of Chemical Engineering, Tsinghua University, 100084 Beijing, P. R. China
| | - Yejun Li
- School of Materials Science and Engineering, Central South University, 410083 Changsha, P. R. China
- Hunan Key Laboratory of Nanophotonics and Devices, School of Physics and Electronics, Central South University, 410083 Changsha, P. R. China
| | - Xiaoming Yuan
- Hunan Key Laboratory of Nanophotonics and Devices, School of Physics and Electronics, Central South University, 410083 Changsha, P. R. China
| | - Gufei Zhang
- POLIMA-Center for Polariton-driven Light-Matter Interactions & Danish Institute for Advanced Study, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Qing Wu
- Information and Network Center, Central South University, 410083 Changsha, P. R. China
| | - Zhou Li
- School of Materials Science and Engineering, Central South University, 410083 Changsha, P. R. China
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17
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Bai J, Tang Y, Lin C, Jiang X, Zhang C, Qin H, Zhou Q, Xiang M, Lian Y, Deng Y. Iron clusters regulate local charge distribution in Fe-N 4 sites to boost oxygen electroreduction. J Colloid Interface Sci 2023; 648:440-447. [PMID: 37302227 DOI: 10.1016/j.jcis.2023.06.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 05/23/2023] [Accepted: 06/04/2023] [Indexed: 06/13/2023]
Abstract
The atomically-dispersed and nitrogen-coordinated iron (FeNC) on a carbon catalyst is a potential non-noble metal catalyst that can replace precious metal electrocatalysts. However, its activity is often unsatisfactory owing to the symmetric charge distribution around the iron matrix. In this study, atomically- dispersed Fe-N4 and Fe nanoclusters loaded with N-doped porous carbon (FeNCs/FeSAs-NC-Z8@34) were rationally fabricated by introducing homologous metal clusters and increasing the N content of the support. FeNCs/FeSAs-NC-Z8@34 exhibited a half-wave potential of 0.918 V, which exceeded that of the commercial benchmark Pt/C catalyst. Theoretical calculations verified that introducing Fe nanoclusters can break the symmetric electronic structure of Fe-N4, thus inducing charge redistribution. Furthermore, it can optimize a part of Fe 3d occupancy orbitals and accelerate OO fracture in OOH* (rate-determining step), thus significantly improving oxygen reduction reaction activity. This work provides a reasonably advanced pathway to modulate the electronic structure of the single-atom center and optimize the catalytic activity of single-atom catalysts.
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Affiliation(s)
- Jirong Bai
- Research Center of secondary Resources and Environment, School of Chemical Engineering and Materials, Changzhou Institute of Technology, Changzhou, 213022, China.
| | - Yiming Tang
- Research Center of secondary Resources and Environment, School of Chemical Engineering and Materials, Changzhou Institute of Technology, Changzhou, 213022, China
| | - Cheng Lin
- Research Center of secondary Resources and Environment, School of Chemical Engineering and Materials, Changzhou Institute of Technology, Changzhou, 213022, China
| | - Xiankai Jiang
- Research Center of secondary Resources and Environment, School of Chemical Engineering and Materials, Changzhou Institute of Technology, Changzhou, 213022, China.
| | - Chunyong Zhang
- School of Chemistry and Environmental Engineering, Jiangsu University of Technology, Changzhou 213001, China
| | - Hengfei Qin
- School of Chemistry and Environmental Engineering, Jiangsu University of Technology, Changzhou 213001, China
| | - Quanfa Zhou
- Research Center of secondary Resources and Environment, School of Chemical Engineering and Materials, Changzhou Institute of Technology, Changzhou, 213022, China
| | - Mei Xiang
- Research Center of secondary Resources and Environment, School of Chemical Engineering and Materials, Changzhou Institute of Technology, Changzhou, 213022, China
| | - Yuebin Lian
- Research Center of secondary Resources and Environment, School of Chemical Engineering and Materials, Changzhou Institute of Technology, Changzhou, 213022, China
| | - Yaoyao Deng
- Research Center of secondary Resources and Environment, School of Chemical Engineering and Materials, Changzhou Institute of Technology, Changzhou, 213022, China.
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18
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Du Z, Deng K, Kan E, Zhan C. Exploring the catalytic activity of graphene-based TM-N xC 4-x single atom catalysts for the oxygen reduction reaction via density functional theory calculation. Phys Chem Chem Phys 2023; 25:13913-13922. [PMID: 37184027 DOI: 10.1039/d3cp01168b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Electrocatalysts for the oxygen reduction reaction (ORR) are extremely crucial for advanced energy conversion technologies, such as fuel cell batteries. A promising ORR catalyst usually should have low overpotentials, rich catalytic sites and low cost. In the past decade, single-atom catalyst (SAC) TM-N4 (TM = Fe, Co, etc.) embedded graphene matrixes have been widely studied for their promising performance and low cost for ORR catalysis, but the effect of coordination on the ORR activity is not fully understood. In this work, we will employ density functional theory (DFT) calculations to systematically investigate the ORR activity of 40 different 3d transition metal single-atom catalysts (SACs) supported on nitrogen-doped graphene supports, ranging from vanadium to zinc. Five different nitrogen coordination configurations (TM-NxC4-x with x = 0, 1, 2, 3, and 4) were studied to reveal how C/N substitution affects the ORR activity. By looking at the stability, free energy diagram, overpotential, and scaling relationship, our calculation showed that partial C substitution can effectively improve the ORR performance of Mn, Co, Ni, and Zn-based SACs. The volcano plot obtained from the scaling relationship indicated that the substitution of N by C could distinctively affect the potential-limiting step in the ORR, which leads to the enhanced or weakened ORR performance. Density of states and d-band center analysis suggested that this coordination-tuned ORR activity can be explained by the shift of the d-band center due to the coordination effect. Finally, four candidates with optimal ORR activity and dynamic stability were proposed from the pool: NiC4, CoNC3, CrN4, and ZnN3C. Our work provides a feasible designing strategy to improve the ORR activity of graphene-based TM-N4 SACs by tuning the coordination environment, which may have potential implication in the high-performance fuel cell development.
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Affiliation(s)
- Zhengwei Du
- Department of Applied Physics, Nanjing University of Science and Technology, Nanjing 210094, China.
| | - Kaiming Deng
- Department of Applied Physics, Nanjing University of Science and Technology, Nanjing 210094, China.
- MIIT Key Laboratory of Semiconductor Microstructure and Quantum Sensing, P. R. China
| | - Erjun Kan
- Department of Applied Physics, Nanjing University of Science and Technology, Nanjing 210094, China.
- MIIT Key Laboratory of Semiconductor Microstructure and Quantum Sensing, P. R. China
| | - Cheng Zhan
- Department of Applied Physics, Nanjing University of Science and Technology, Nanjing 210094, China.
- MIIT Key Laboratory of Semiconductor Microstructure and Quantum Sensing, P. R. China
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19
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Manopo J, Lubis TP, Maryono MAME, Arifin P, Winata T, Widita R, Darma Y. Strongly bound Wannier-Mott exciton in pristine (LaO)MnAs and origin of ferrimagnetism in F-doped (LaO)MnAs. RSC Adv 2023; 13:14033-14040. [PMID: 37181508 PMCID: PMC10167672 DOI: 10.1039/d3ra01506h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 04/23/2023] [Indexed: 05/16/2023] Open
Abstract
We study the electronic, magnetic, and optical properties of (LaO1-xFx)MnAs (x = 0, 0.0625, 0.125, 0.25) systems, calculated using the generalized gradient approximation (GGA) corrected by Hubbard energy (U) = 1 eV. For x = 0, this system shows equal bandgap (Eg) values for spin-up and spin-down of 0.826 eV, with antiferromagnetic (AFM) properties and local magnetic moment in the Mn site of 3.86 μB per Mn. By doping F with x = 0.0625, the spin-up and spin-down Eg values decrease to 0.778 and 0.798 eV, respectively. This system, along with antiferromagnetic properties, also has a local magnetic moment in the Mn site of 3.83 μB per Mn. Increasing doping F to x = 0.125 induces increases of Eg to 0.827 and 0.839 eV for spin-up and spin-down. However, the AFM remains, where μMn slightly decreases to 3.81 μB per Mn. Furthermore, the excess electron from the F ion induces the Fermi level to move toward the conduction band and changes the bandgap type from indirect bandgap (Γ → M) to direct bandgap (Γ → Γ). Increasing x to 25% induces the decrease of spin-up and spin-down Eg to 0.488 and 0.465 eV, respectively. This system shows that the AFM changes to ferrimagnetism (FIM) for x = 25%, with a total magnetic moment of 0.78 μB per cell, which is mostly contributed by Mn 3d and As 4p local magnetic moments. The change from AFM to FIM behavior results from competition between superexchange AFM ordering and Stoner's exchange ferromagnetic ordering. Pristine (LaO)MnAs exhibits high excitonic binding energy (∼146.5 meV) due to a flat band structure. Our study shows that doping F in the (LaO)MnAs system significantly modifies the electronic, magnetic, and optical properties for novel advanced device applications.
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Affiliation(s)
- Jessie Manopo
- Quantum Semiconductor and Devices Lab, Department of Physics, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology Jalan Ganesha 10 Bandung 40132 Indonesia
- Physics of Electronic Materials Research Division, Department of Physics, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology Jalan Ganesha 10 Bandung 40132 Indonesia
- Research Collaboration Center for Quantum Technology 2.0 Bandung 40132 Indonesia
| | - Tio Prince Lubis
- Quantum Semiconductor and Devices Lab, Department of Physics, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology Jalan Ganesha 10 Bandung 40132 Indonesia
- Physics of Electronic Materials Research Division, Department of Physics, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology Jalan Ganesha 10 Bandung 40132 Indonesia
| | - Muhammad Arief Mustajab Enha Maryono
- Physics of Electronic Materials Research Division, Department of Physics, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology Jalan Ganesha 10 Bandung 40132 Indonesia
| | - Pepen Arifin
- Physics of Electronic Materials Research Division, Department of Physics, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology Jalan Ganesha 10 Bandung 40132 Indonesia
| | - Toto Winata
- Physics of Electronic Materials Research Division, Department of Physics, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology Jalan Ganesha 10 Bandung 40132 Indonesia
| | - Rena Widita
- Nuclear Physics and Biophysics Research Division, Department of Physics, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology Jalan Ganesha 10 Bandung 40132 Indonesia
| | - Yudi Darma
- Quantum Semiconductor and Devices Lab, Department of Physics, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology Jalan Ganesha 10 Bandung 40132 Indonesia
- Physics of Electronic Materials Research Division, Department of Physics, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology Jalan Ganesha 10 Bandung 40132 Indonesia
- Research Collaboration Center for Quantum Technology 2.0 Bandung 40132 Indonesia
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20
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Liu K, Fu J, Luo T, Ni G, Li H, Zhu L, Wang Y, Lin Z, Sun Y, Cortés E, Liu M. Potential-Dependent Active Moiety of Fe-N-C Catalysts for the Oxygen Reduction Reaction. J Phys Chem Lett 2023; 14:3749-3756. [PMID: 37043683 DOI: 10.1021/acs.jpclett.3c00583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
The real active moiety of Fe-N-C single-atom catalysts (SACs) during the oxygen reduction reaction (ORR) depends on the applied potential. Here, we examine the ORR activity of various SAC active moieties (Fe-N4, Fe-(OH)N4, Fe-(O2)N4, and Fe-(OH2)N4) over a wide potential window ranging from -0.8 to 1.0 V (vs. SHE) using constant potential density functional theory calculations. We show that the ORR activity of the Fe-N4 moiety is hindered by the slow *OH protonation, while the Fe-(OH2)N4 (0.4 V ≤ U ≤ 1.0 V), *O2-assisted Fe-N4 (-0.6 V ≤ U ≤ 0.2 V), and Fe-(OH)N4 (U = -0.8 V) moieties dominate the ORR activity of the Fe-N-C catalysts at different potential windows. These oxygenated species modified the single-atom Fe sites and can promote *OH protonation by regulating the electron occupancy of the Fe 3dz2 (spin-up) and Fe 3dxz (spin-down) orbitals. Overall, our findings provide guidance for understanding the active moieties of SACs.
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Affiliation(s)
- Kang Liu
- School of Metallurgy and Environment, Central South University, Changsha, Hunan 410083, P. R. China
- Hunan Joint International Research Center for Carbon Dioxide Resource Utilization, School of Physics and Electronics, Central South University, Changsha, Hunan 410083, P. R. China
| | - Junwei Fu
- Hunan Joint International Research Center for Carbon Dioxide Resource Utilization, School of Physics and Electronics, Central South University, Changsha, Hunan 410083, P. R. China
| | - Tao Luo
- Hunan Joint International Research Center for Carbon Dioxide Resource Utilization, School of Physics and Electronics, Central South University, Changsha, Hunan 410083, P. R. China
| | - Ganghai Ni
- Hunan Joint International Research Center for Carbon Dioxide Resource Utilization, School of Physics and Electronics, Central South University, Changsha, Hunan 410083, P. R. China
| | - Hongmei Li
- Hunan Joint International Research Center for Carbon Dioxide Resource Utilization, School of Physics and Electronics, Central South University, Changsha, Hunan 410083, P. R. China
- School of Materials Science and Engineering, Zhengzhou University, Zhengzhou, Henan 450001, P. R. China
| | - Li Zhu
- Nanoinstitute Munich, Faculty of Physics, Ludwig Maximilians Universität München, 80539 München, Germany
| | - Ye Wang
- School of Energy and Power Engineering, Beihang University, Beijing 100191, China
| | - Zhang Lin
- School of Metallurgy and Environment, Central South University, Changsha, Hunan 410083, P. R. China
| | - Yifei Sun
- School of Energy and Power Engineering, Beihang University, Beijing 100191, China
- Research Center for Advanced Energy and Carbon Neutrality, Beihang University, Beijing 100191, China
| | - Emiliano Cortés
- Nanoinstitute Munich, Faculty of Physics, Ludwig Maximilians Universität München, 80539 München, Germany
| | - Min Liu
- Hunan Joint International Research Center for Carbon Dioxide Resource Utilization, School of Physics and Electronics, Central South University, Changsha, Hunan 410083, P. R. China
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21
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Barrio J, Pedersen A, Sarma SC, Bagger A, Gong M, Favero S, Zhao CX, Garcia-Serres R, Li AY, Zhang Q, Jaouen F, Maillard F, Kucernak A, Stephens IEL, Titirici MM. FeNC Oxygen Reduction Electrocatalyst with High Utilization Penta-Coordinated Sites. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2211022. [PMID: 36739474 DOI: 10.1002/adma.202211022] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 01/11/2023] [Indexed: 06/18/2023]
Abstract
Atomic Fe in N-doped carbon (FeNC) electrocatalysts for oxygen (O2 ) reduction at the cathode of proton exchange membrane fuel cells are the most promising alternative to platinum-group-metal catalysts. Despite recent progress on atomic FeNC O2 reduction, their controlled synthesis and stability for practical applications remain challenging. A two-step synthesis approach has recently led to significant advances in terms of Fe-loading and mass activity; however, the Fe utilization remains low owing to the difficulty of building scaffolds with sufficient porosity that electrochemically exposes the active sites. Herein, this issue is addressed by coordinating Fe in a highly porous nitrogen-doped carbon support (≈3295 m2 g-1 ), prepared by pyrolysis of inexpensive 2,4,6-triaminopyrimidine and a Mg2+ salt active site template and porogen. Upon Fe coordination, a high electrochemical active site density of 2.54 × 1019 sites gFeNC -1 and a record 52% FeNx electrochemical utilization based on in situ nitrite stripping are achieved. The Fe single atoms are characterized pre- and post-electrochemical accelerated stress testing by aberration-corrected high-angle annular dark field scanning transmission electron microscopy, showing no Fe clustering. Moreover, ex situ X-ray absorption spectroscopy and low-temperature Mössbauer spectroscopy suggest the presence of penta-coordinated Fe sites, which are further studied by density functional theory calculations.
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Affiliation(s)
- Jesús Barrio
- Department of Materials, Royal School of Mines, Imperial College London, London, SW7 2AZ, UK
- Department of Chemical Engineering, Imperial College London, London, SW7 2AZ, UK
| | - Angus Pedersen
- Department of Materials, Royal School of Mines, Imperial College London, London, SW7 2AZ, UK
- Department of Chemical Engineering, Imperial College London, London, SW7 2AZ, UK
| | - Saurav Ch Sarma
- Department of Chemical Engineering, Imperial College London, London, SW7 2AZ, UK
| | - Alexander Bagger
- Department of Chemical Engineering, Imperial College London, London, SW7 2AZ, UK
| | - Mengjun Gong
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, White City Campus, London, W12 0BZ, UK
| | - Silvia Favero
- Department of Chemical Engineering, Imperial College London, London, SW7 2AZ, UK
| | - Chang-Xin Zhao
- Department of Chemical Engineering, Tsinghua University, 1 Tsinghua Road, Beijing, 100084, P. R. China
| | - Ricardo Garcia-Serres
- Chemistry and Biology of Metals Laboratory, CNRS, CEA, IRIG, University Grenoble Alpes, 17 Rue Des Martyrs, Grenoble, 38000, France
| | - Alain Y Li
- Department of Chemical Engineering, Imperial College London, London, SW7 2AZ, UK
| | - Qiang Zhang
- Department of Chemical Engineering, Tsinghua University, 1 Tsinghua Road, Beijing, 100084, P. R. China
| | - Frédéric Jaouen
- Institute of Molecular Chemistry and Materials Sciences, CNRS, ENSCM, University of Montpellier, 1919 route de Mende, Montpellier, 34293, France
| | - Frédéric Maillard
- Laboratory of Electrochemistry and Physico-Chemistry of Materials and Interfaces (LEPMI), CNRS, University Savoie Mont-Blanc, Grenoble-INP, University Grenoble Alpes, Grenoble, 38000, France
| | - Anthony Kucernak
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, White City Campus, London, W12 0BZ, UK
| | - Ifan E L Stephens
- Department of Materials, Royal School of Mines, Imperial College London, London, SW7 2AZ, UK
| | - Maria-Magdalena Titirici
- Department of Chemical Engineering, Imperial College London, London, SW7 2AZ, UK
- Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, 2-1-1 Katahira, Aobaku, Sendai, Miyagi, 980-8577, Japan
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22
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Menachekanian S, Voegtle MJ, Warburton RE, Hammes-Schiffer S, Dawlaty JM. Inductive Effect Alone Cannot Explain Lewis Adduct Formation and Dissociation at Electrode Interfaces. J Am Chem Soc 2023; 145:5759-5768. [PMID: 36862607 DOI: 10.1021/jacs.2c12370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/03/2023]
Abstract
Understanding breaking and formation of Lewis bonds at an electrified interface is relevant to a large range of phenomena, including electrocatalysis and electroadsorption. The complexities of interfacial environments and associated reactions often impede a systematic understanding of this type of bond at interfaces. To address this challenge, we report the creation of a main group classic Lewis acid-base adduct on an electrode surface and its behavior under varying electrode potentials. The Lewis base is a self-assembled monolayer of mercaptopyridine and the Lewis acid is BF3, forming a Lewis bond between nitrogen and boron. The bond is stable at positive potentials but cleaves at potentials more negative of approximately -0.3 V vs Ag/AgCl without an associated current. We also show that if the Lewis acid BF3 is supplied from a reservoir of Li+BF4- electrolyte, the cleavage is completely reversible. We propose that the N-B Lewis bond is affected both by the field-induced intramolecular polarization (electroinduction) and by the ionic structures and ionic equilibria near the electrode. Our results indicate that the second effect is responsible for the Lewis bond cleavage at negative potentials. This work is relevant to understanding the fundamentals of electrocatalytic and electroadsorption processes.
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Affiliation(s)
- Sevan Menachekanian
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Matthew J Voegtle
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | | | | | - Jahan M Dawlaty
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
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23
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Liu T, Wang Y, Li Y. How pH Affects the Oxygen Reduction Reactivity of Fe–N–C Materials. ACS Catal 2023. [DOI: 10.1021/acscatal.2c05540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Tianyang Liu
- Jiangsu Key Laboratory of New Power Batteries, Jiangsu Collaborative Innovation Centre of Biomedical Functional Materials, School of Chemistry and Materials Science, Nanjing Normal University, Nanjing, Jiangsu 210023, P.R. China
| | - Yu Wang
- Jiangsu Key Laboratory of New Power Batteries, Jiangsu Collaborative Innovation Centre of Biomedical Functional Materials, School of Chemistry and Materials Science, Nanjing Normal University, Nanjing, Jiangsu 210023, P.R. China
| | - Yafei Li
- Jiangsu Key Laboratory of New Power Batteries, Jiangsu Collaborative Innovation Centre of Biomedical Functional Materials, School of Chemistry and Materials Science, Nanjing Normal University, Nanjing, Jiangsu 210023, P.R. China
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24
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Zhang J, Sun Y, Xiao M, Liu J. Candied Haws-Like Fe-N-C Catalysts with Broadened Carbon Interlayer Spacing for Efficient Zinc-Air Battery. ACS APPLIED MATERIALS & INTERFACES 2023; 15:953-962. [PMID: 36576782 DOI: 10.1021/acsami.2c16766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
As efficient nonprecious metal catalysts for oxygen reduction reaction (ORR), Fe-N-C materials are one of the most promising alternatives to Pt-based catalysts for fuel cells and metal-air batteries. However, the intrinsically low density of key active sites like FeN4 moieties hampers their commercial applications. Herein, we provide a smart strategy to construct a candied haws-like Fe-N-C catalyst (CH-FeNC) with broadened carbon interplanar spacing (>4 Å), starting with trehalose as a structure-built brick coupled with a zinc-zeolite imidazole framework (ZIF-8) and polyaniline (PANI) and then followed by copyrolysis carbonization of them. The obtained CH-FeNC exhibits half-wave potentials of 0.92 and 0.90 V (vs RHE) before and after 10,000 cycles in 0.1 M KOH, which are superior to the 0.90 and 0.85 V obtained by commercial Pt/C for ORR. The power density of a homemade zinc-air battery equipped with the catalyst is up to 131 mW cm-2, greater than that of Pt/C (124 mW cm-2). The extended X-ray absorption fine structure (EXAFS) results and density functional theory (DFT) theoretical calculations reveal that there exists enriched zigzag or armchair edge-hosted FeN4 active sites, located at the abundant interface between carbon components in this composite. Furthermore, the unique broadened carbon interlayer spacing plays a key role in deciding the ORR rate in alkaline but not in acidic environments because there exists a fifth ligand of active Fe in the form of FeN4 centers coupled with SO42- and ClO4- from acids.
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Affiliation(s)
- Jin Zhang
- Beijing University of Chemical Technology, No. 15 North Third Ring East Road, Beijing100029, P. R. China
| | - Yanhui Sun
- Beijing University of Chemical Technology, No. 15 North Third Ring East Road, Beijing100029, P. R. China
| | - Mingyue Xiao
- Beijing University of Chemical Technology, No. 15 North Third Ring East Road, Beijing100029, P. R. China
| | - Jingjun Liu
- Beijing University of Chemical Technology, No. 15 North Third Ring East Road, Beijing100029, P. R. China
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25
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Exploring the Potential Energy Surface of Pt 6 Sub-Nano Clusters Deposited over Graphene. Int J Mol Sci 2023; 24:ijms24010870. [PMID: 36614312 PMCID: PMC9820941 DOI: 10.3390/ijms24010870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 12/22/2022] [Accepted: 12/30/2022] [Indexed: 01/05/2023] Open
Abstract
Catalytic systems based on sub-nanoclusters deposited over different supports are promising for very relevant chemical transformations such as many electrocatalytic processes as the ORR. These systems have been demonstrated to be very fluxional, as they are able to change shape and interconvert between each other either alone or in the presence of adsorbates. In addition, an accurate representation of their catalytic activity requires the consideration of ensemble effects and not a single structure alone. In this sense, a reliable theoretical methodology should assure an accurate and extensive exploration of the potential energy surface to include all the relevant structures and with correct relative energies. In this context, we applied DFT in conjunction with global optimization techniques to obtain and analyze the characteristics of the many local minima of Pt6 sub-nanoclusters over a carbon-based support (graphene)-a system with electrocatalytic relevance. We also analyzed the magnetism and the charge transfer between the clusters and the support and paid special attention to the dependence of dispersion effects on the ensemble characteristics. We found that the ensembles computed with and without dispersion corrections are qualitatively similar, especially for the lowest-in-energy clusters, which we attribute to a (mainly) covalent binding to the surface. However, there are some significant variations in the relative stability of some clusters, which would significantly affect their population in the ensemble composition.
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26
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Hutchison P, Warburton RE, Surendranath Y, Hammes-Schiffer S. Correlation between Electronic Descriptor and Proton-Coupled Electron Transfer Thermodynamics in Doped Graphite-Conjugated Catalysts. J Phys Chem Lett 2022; 13:11216-11222. [PMID: 36445816 DOI: 10.1021/acs.jpclett.2c03278] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Graphite-conjugated catalysts (GCCs) provide a powerful framework for investigating correlations between electronic structure features and chemical reactivity of single-site heterogeneous catalysts. GCC-phenazine undergoes proton-coupled electron transfer (PCET) involving protonation of phenazine at its two nitrogen atoms with the addition of two electrons. Herein, this PCET reaction is investigated in the presence of defects, such as heteroatom dopants, in the graphitic surface. The proton-coupled redox potentials, EPCET, are computed using a constant potential periodic density functional theory (DFT) strategy. The electronic states directly involved in PCET for GCC-phenazine exhibit the same nitrogen orbital character as those for molecular phenazine. The energy εLUS of this phenazine-related lowest unoccupied electronic state in GCC-phenazine is identified as a descriptor for changes in PCET thermodynamics. Importantly, εLUS is obtained from only a single DFT calculation but can predict EPCET, which requires many such calculations. Similar electronic features may be useful descriptors for thermodynamic properties of other single-site catalysts.
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Affiliation(s)
- Phillips Hutchison
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Robert E Warburton
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Yogesh Surendranath
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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27
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Metal-Organic Framework-Derived Atomically Dispersed Co-N-C Electrocatalyst for Efficient Oxygen Reduction Reaction. Catalysts 2022. [DOI: 10.3390/catal12111462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
In this work, an atomically dispersed cobalt-nitrogen-carbon (Co-N-C) catalyst is prepared for the oxygen reduction reaction (ORR) by using a metal-organic framework (MOF) as a self-sacrifice template under high-temperature pyrolysis. Spherical aberration-corrected electron microscopy is employed to confirm the atomic dispersion of high-density Co atoms on the nitrogen-doped carbon scaffold. The X-ray photoelectron spectroscopy results verify the existence of Co-N-C active sites and their content changes with the Co content. The electrochemical results show that the electrocatalytic activity shows a volcano-shaped relationship, which increases with the Co content from 0 to 0.99 wt.% and then decreases when the presence of Co nanoparticles at 1.61 wt.%. The atomically dispersed Co-N-C catalyst with Co content of 0.99 wt.% shows an onset potential of 0.96 V vs. reversible hydrogen electrode (RHE) and a half-wave potential of 0.89 V vs. RHE toward ORR. The excellent ORR activity is attributed to the high density of the Co-N-C sites with high intrinsic activity and high specific surface area to expose more active sites.
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28
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Munarriz J, Zhang Z, Sautet P, Alexandrova AN. Graphite-Supported Pt n Cluster Electrocatalysts: Major Change of Active Sites as a Function of the Applied Potential. ACS Catal 2022. [DOI: 10.1021/acscatal.2c04643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Julen Munarriz
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 607 Charles E. Young Drive, Los Angeles, California 90095-1569, United States
- Departamento de Química Física y Analítica, Universidad de Oviedo, Julián Clavería no. 8, Campus Universitario de El Cristo, Oviedo, 33006 Spain
| | - Zisheng Zhang
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 607 Charles E. Young Drive, Los Angeles, California 90095-1569, United States
| | - Philippe Sautet
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 607 Charles E. Young Drive, Los Angeles, California 90095-1569, United States
- California NanoSystem Institute, University of California, Los Angeles, 607 Charles E. Young Drive, Los Angeles, California 90095-1569, United States
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, 5531 Boelter Hall, Los Angeles, California 90095, United States
| | - Anastassia N. Alexandrova
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 607 Charles E. Young Drive, Los Angeles, California 90095-1569, United States
- California NanoSystem Institute, University of California, Los Angeles, 607 Charles E. Young Drive, Los Angeles, California 90095-1569, United States
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Hu X, Chen S, Chen L, Tian Y, Yao S, Lu Z, Zhang X, Zhou Z. What is the Real Origin of the Activity of Fe-N-C Electrocatalysts in the O 2 Reduction Reaction? Critical Roles of Coordinating Pyrrolic N and Axially Adsorbing Species. J Am Chem Soc 2022; 144:18144-18152. [PMID: 36135972 DOI: 10.1021/jacs.2c08743] [Citation(s) in RCA: 58] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Fe-N-C electrocatalysts have emerged as promising substitutes for Pt-based catalysts for the oxygen reduction reaction (ORR). However, their real catalytic active site is still under debate. The underlying roles of different types of coordinating N including pyridinic and pyrrolic N in catalytic performance require thorough clarification. In addition, how to understand the pH-dependent activity of Fe-N-C catalysts is another urgent issue. Herein, we comprehensively studied 13 different N-coordinated FeNxC configurations and their corresponding ORR activity through simulations which mimic the realistic electrocatalytic environment on the basis of constant-potential implicit solvent models. We demonstrate that coordinating pyrrolic N contributes to a higher activity than pyridinic N, and pyrrolic FeN4C exhibits the highest activity in acidic media. Meanwhile, the in situ active site transformation to *O-FeN4C and *OH-FeN4C clarifies the origin of the higher activity of Fe-N-C in alkaline media. These findings can provide indispensable guidelines for rational design of better durable Fe-N-C catalysts.
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Affiliation(s)
- Xu Hu
- School of Materials Science and Engineering, Institute of New Energy Material Chemistry, Renewable Energy Conversion and Storage Center (ReCast), Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Nankai University, Tianjin 300350, China
| | - Suya Chen
- School of Materials Science and Engineering, Institute of New Energy Material Chemistry, Renewable Energy Conversion and Storage Center (ReCast), Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Nankai University, Tianjin 300350, China
| | - Letian Chen
- School of Materials Science and Engineering, Institute of New Energy Material Chemistry, Renewable Energy Conversion and Storage Center (ReCast), Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Nankai University, Tianjin 300350, China
| | - Yun Tian
- School of Chemical Engineering, Zhengzhou University, Zhengzhou 450001, Henan, China
| | - Sai Yao
- School of Materials Science and Engineering, Institute of New Energy Material Chemistry, Renewable Energy Conversion and Storage Center (ReCast), Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Nankai University, Tianjin 300350, China
| | - Zhengyu Lu
- School of Materials Science and Engineering, Institute of New Energy Material Chemistry, Renewable Energy Conversion and Storage Center (ReCast), Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Nankai University, Tianjin 300350, China
| | - Xu Zhang
- School of Chemical Engineering, Zhengzhou University, Zhengzhou 450001, Henan, China
| | - Zhen Zhou
- School of Materials Science and Engineering, Institute of New Energy Material Chemistry, Renewable Energy Conversion and Storage Center (ReCast), Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Nankai University, Tianjin 300350, China.,School of Chemical Engineering, Zhengzhou University, Zhengzhou 450001, Henan, China
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