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Elimination of Indoor Volatile Organic Compounds on Au/SBA-15 Catalysts: Insights into the Nature, Size, and Dispersion of the Active Sites and Reaction Mechanism. Catalysts 2022. [DOI: 10.3390/catal12111365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Gold catalysts, with different particle sizes ranging from 19 to 556 Å, and supported on SBA-15 mesoporous silica, were prepared by using deposition-precipitation, co-precipitation, and impregnation methods. All samples were characterised by TEM, EXAFS, XPS, XRD, CFR (Continuous Flow Reactor), and TPR. The sample which proved to have the highest activity was characterised by TAP (Temporal Analysis of Products) as well. XPS, wide-angle XRD, EXAFS, and H2-TPR measurements and data analysis confirmed that gold was present as Au0 only on all samples. The size of the Au nanoparticle was determined from TEM measurements and confirmed through wide-angle XRD measurements. EXAFS measurements showed that as the Au-Au coordination number decreased the Au-Au bond length decreased. TEM data analysis revealed a dispersion range from 58% (for the smallest particle size) to 2% (for the highest particle size). For Au particles’ sized lower that 60 Å, the Au dispersion was determined using a literature correlation between the dispersion and EXAFS Au-Au coordination number, and was in good agreement with the dispersion data obtained from TEM. The Au dispersion decreased as the particle size increased. CFR experiments validated the relationship between the size of the gold particles in a sample and the sample’s catalytic activity towards acetone oxidation. The lowest temperature for the acetone 100% conversion, i.e., 250 °C, was observed over the reduced catalyst sample with the smallest particle size. This sample not only showed the highest catalytic activity towards acetone conversion, but, at the same time, showed high reaction stability, as catalyst lifetime tests, performed for 25 h in a CFR at 270 °C for the as-synthesised sample, and at 220 °C for the reduced sample, have confirmed. TAP (Temporal Analysis of Products) measurements and data analysis confirmed a weak competitive adsorption of acetone and oxygen over the Au/SBA-15 sample. Based on TAP data, a combination of Eley–Rideal and Langmuir–Hinshelwood mechanisms for acetone complete oxidation was proposed.
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Abstract
The field of single-atom catalysis (SAC) has expanded greatly in recent years. While there has been much success developing new synthesis methods, a fundamental disconnect exists between most experiments and the theoretical computations used to model them. The real catalysts are based on powder supports, which inevitably contain a multitude of different facets, different surface sites, defects, hydroxyl groups, and other contaminants due to the environment. This makes it extremely difficult to determine the structure of the active SAC site using current techniques. To be tractable, computations aimed at modeling SAC utilize periodic boundary conditions and low-index facets of an idealized support. Thus, the reaction barriers and mechanisms determined computationally represent, at best, a plausibility argument, and there is a strong chance that some critical aspect is omitted. One way to better understand what is plausible is by experimental modeling, i.e., comparing the results of computations to experiments based on precisely defined single-crystalline supports prepared in an ultrahigh-vacuum (UHV) environment. In this review, we report the status of the surface-science literature as it pertains to SAC. We focus on experimental work on supports where the site of the metal atom are unambiguously determined from experiment, in particular, the surfaces of rutile and anatase TiO2, the iron oxides Fe2O3 and Fe3O4, as well as CeO2 and MgO. Much of this work is based on scanning probe microscopy in conjunction with spectroscopy, and we highlight the remarkably few studies in which metal atoms are stable on low-index surfaces of typical supports. In the Perspective section, we discuss the possibility for expanding such studies into other relevant supports.
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Affiliation(s)
- Florian Kraushofer
- Institute of Applied Physics, Technische Universitat Wien, 1040 Vienna, Austria
| | - Gareth S. Parkinson
- Institute of Applied Physics, Technische Universitat Wien, 1040 Vienna, Austria
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Singh B, Gawande MB, Kute AD, Varma RS, Fornasiero P, McNeice P, Jagadeesh RV, Beller M, Zbořil R. Single-Atom (Iron-Based) Catalysts: Synthesis and Applications. Chem Rev 2021; 121:13620-13697. [PMID: 34644065 DOI: 10.1021/acs.chemrev.1c00158] [Citation(s) in RCA: 75] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Supported single-metal atom catalysts (SACs) are constituted of isolated active metal centers, which are heterogenized on inert supports such as graphene, porous carbon, and metal oxides. Their thermal stability, electronic properties, and catalytic activities can be controlled via interactions between the single-metal atom center and neighboring heteroatoms such as nitrogen, oxygen, and sulfur. Due to the atomic dispersion of the active catalytic centers, the amount of metal required for catalysis can be decreased, thus offering new possibilities to control the selectivity of a given transformation as well as to improve catalyst turnover frequencies and turnover numbers. This review aims to comprehensively summarize the synthesis of Fe-SACs with a focus on anchoring single atoms (SA) on carbon/graphene supports. The characterization of these advanced materials using various spectroscopic techniques and their applications in diverse research areas are described. When applicable, mechanistic investigations conducted to understand the specific behavior of Fe-SACs-based catalysts are highlighted, including the use of theoretical models.
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Affiliation(s)
- Baljeet Singh
- CICECO-Aveiro Institute of Materials, University of Aveiro, Aveiro, 3810-193 Portugal
| | - Manoj B Gawande
- Department of Industrial and Engineering Chemistry, Institute of Chemical Technology Mumbai-Marathwada Campus, Jalna 431213, Maharashtra, India
| | - Arun D Kute
- Department of Industrial and Engineering Chemistry, Institute of Chemical Technology Mumbai-Marathwada Campus, Jalna 431213, Maharashtra, India
| | - Rajender S Varma
- Regional Centre of Advanced Technologies and Materials, Czech Advanced Technology and Research Institute, Palacký University, 779 00 Olomouc, Czech Republic
| | - Paolo Fornasiero
- Department of Chemical and Pharmaceutical Sciences, Center for Energy, Environment and Transport Giacomo Ciamiciam, INSTM Trieste Research Unit and ICCOM-CNR Trieste Research Unit, University of Trieste, Via L. Giorgieri 1, 34127 Trieste, Italy
| | - Peter McNeice
- Leibniz-Institut für Katalyse e. V., Albert-Einstein-Straße 29a, 18059 Rostock, Germany
| | - Rajenahally V Jagadeesh
- Leibniz-Institut für Katalyse e. V., Albert-Einstein-Straße 29a, 18059 Rostock, Germany.,Department of Chemistry, REVA University, Bangalore 560064, India
| | - Matthias Beller
- Leibniz-Institut für Katalyse e. V., Albert-Einstein-Straße 29a, 18059 Rostock, Germany
| | - Radek Zbořil
- Regional Centre of Advanced Technologies and Materials, Czech Advanced Technology and Research Institute, Palacký University, 779 00 Olomouc, Czech Republic.,CEET Nanotechnology Centre, VŠB-Technical University of Ostrava, 17. Listopadu 2172/15, 708 00 Ostrava-Poruba, Czech Republic
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Kaiser SK, Chen Z, Faust Akl D, Mitchell S, Pérez-Ramírez J. Single-Atom Catalysts across the Periodic Table. Chem Rev 2020; 120:11703-11809. [PMID: 33085890 DOI: 10.1021/acs.chemrev.0c00576] [Citation(s) in RCA: 347] [Impact Index Per Article: 86.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Isolated atoms featuring unique reactivity are at the heart of enzymatic and homogeneous catalysts. In contrast, although the concept has long existed, single-atom heterogeneous catalysts (SACs) have only recently gained prominence. Host materials have similar functions to ligands in homogeneous catalysts, determining the stability, local environment, and electronic properties of isolated atoms and thus providing a platform for tailoring heterogeneous catalysts for targeted applications. Within just a decade, we have witnessed many examples of SACs both disrupting diverse fields of heterogeneous catalysis with their distinctive reactivity and substantially enriching our understanding of molecular processes on surfaces. To date, the term SAC mostly refers to late transition metal-based systems, but numerous examples exist in which isolated atoms of other elements play key catalytic roles. This review provides a compositional encyclopedia of SACs, celebrating the 10th anniversary of the introduction of this term. By defining single-atom catalysis in the broadest sense, we explore the full elemental diversity, joining different areas across the whole periodic table, and discussing historical milestones and recent developments. In particular, we examine the coordination structures and associated properties accessed through distinct single-atom-host combinations and relate them to their main applications in thermo-, electro-, and photocatalysis, revealing trends in element-specific evolution, host design, and uses. Finally, we highlight frontiers in the field, including multimetallic SACs, atom proximity control, and possible applications for multistep and cascade reactions, identifying challenges, and propose directions for future development in this flourishing field.
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Affiliation(s)
- Selina K Kaiser
- Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 1, 8093 Zurich, Switzerland
| | - Zupeng Chen
- Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 1, 8093 Zurich, Switzerland
| | - Dario Faust Akl
- Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 1, 8093 Zurich, Switzerland
| | - Sharon Mitchell
- Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 1, 8093 Zurich, Switzerland
| | - Javier Pérez-Ramírez
- Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 1, 8093 Zurich, Switzerland
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Thorough Search Analysis of Extended X-ray Absorption Fine Structure Data for Complex Molecules and Nanomaterials Applications. E-JOURNAL OF SURFACE SCIENCE AND NANOTECHNOLOGY 2020. [DOI: 10.1380/ejssnt.2020.249] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Ma J, Wu S, Yuan Y, Mao H, Lee JY, Kang B. Graphyne-anchored single Fe atoms as efficient CO oxidation catalysts as predicted by DFT calculations. Phys Chem Chem Phys 2020; 22:6004-6009. [PMID: 32123892 DOI: 10.1039/d0cp00178c] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
By performing first-principles calculations, CO oxidation catalyzed by Fe-embedded defective α-graphyne was systematically investigated. It was found that Fe atoms were strongly anchored at the sp-C vacancy site of α-graphyne with a large binding energy of -5.28 eV and effectively adsorbed and activated O2 molecules. Then, we systematically compared CO oxidation by activated O2via Langmuir-Hinshelwood (LH) and Eley-Rideal (ER) mechanisms. The calculated potential energy surfaces show that the Fe-doped α-graphyne can efficiently oxidize CO via the ER mechanism, in which the threshold of the rate determining step is 0.77 eV. Furthermore, Fe doping shows little effect on the diffusivities of CO, O2, and CO2, which can further enhance its catalytic performance.
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Affiliation(s)
- Jiapeng Ma
- School of Chemistry and Chemical Engineering, University of Jinan, Jinan, Shandong 250022, P. R. China. and Department of Chemistry, Sungkyunkwan University, Suwon, 16419, Republic of Korea.
| | - Si Wu
- School of Chemistry and Chemical Engineering, University of Jinan, Jinan, Shandong 250022, P. R. China.
| | - Yuan Yuan
- School of Chemistry and Chemical Engineering, University of Jinan, Jinan, Shandong 250022, P. R. China.
| | - Hui Mao
- Pharmaceutical and Material Engineering School, Jinhua Polytechnic, Jinhua, 321007, Zhejiang, P. R. China.
| | - Jin Yong Lee
- School of Chemistry and Chemical Engineering, University of Jinan, Jinan, Shandong 250022, P. R. China. and Department of Chemistry, Sungkyunkwan University, Suwon, 16419, Republic of Korea.
| | - Baotao Kang
- School of Chemistry and Chemical Engineering, University of Jinan, Jinan, Shandong 250022, P. R. China.
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Influences of MgO(001) and TiO2(101) Supports on the Structures and Properties of Au Nanoclusters. Catalysts 2019. [DOI: 10.3390/catal10010016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Due to the unique structures, photoelectric properties, good catalytic activity, and broad potential applications, gold nanoclusters (Au n ) received extensive attention in catalysis, bioengineering, environmental engineering, and so on. In the present work, the structures and properties of Au n adsorbed on the MgO(001) and TiO 2 (101) surfaces were investigated by density functional theory. The results showed that the catalytic properties of Au n will be enhanced when Au n is adsorbed on certain supports. Because the difference of the outer electronic structure of metals in supports, the direction of the charge transfer was different, thus inducing the different charge distribution on Au n . When Au n was adsorbed on MgO(001) [TiO 2 (101)] surface, Au n will have negative [positive] charges and thus higher catalytic activity in oxidation [reduction] reaction. The variation of surface charges caused by the support makes Au n possess different catalytic activity in different systems. Moreover, the electronic structure of the support will make an obvious influence on the s and d density of states of Au n , which should be the intrinsic reason that induces the variations of its structure and properties. These results should be an important theoretical reference for designing Au n as the photocatalyst applied to the different oxidation and reduction reactions.
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Takakusagi S, Iwasawa Y, Asakura K. Premodified Surface Method to Obtain Ultra-Highly Dispersed Metals and their 3D Structure Control on an Oxide Single-Crystal Surface. CHEM REC 2018; 19:1244-1255. [PMID: 30203911 DOI: 10.1002/tcr.201800088] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Accepted: 08/20/2018] [Indexed: 01/23/2023]
Abstract
Precise control of the three-dimensional (3D) structure of highly dispersed metal species such as metal complexes and clusters attached to an oxide surface has been important for the development of next-generation high-performance heterogeneous catalysts. However, this is not easily achieved for the following reasons. (1) Metal species are easily aggregated on an oxide surface, which makes it difficult to control their size and orientation definitely. (2) Determination of the 3D structure of the metal species on an oxide powder surface is hardly possible. To overcome these difficulties, we have developed the premodified surface method, where prior to metal deposition, the oxide surface is premodified with a functional organic molecule that can strongly coordinate to a metal atom. This method has successfully provided a single metal dispersion on an oxide single-crystal surface with the 3D structure precisely determined by polarization-dependent total reflection fluorescence X-ray absorption fine structure (PTRF-XAFS). Here we describe our recent results on ultra-high dispersions of various metal atoms on TiO2 (110) surfaces premodified with mercapto compounds, and show the possibility of fine tuning and orientation control of the surface metal 3D structures.
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Affiliation(s)
- Satoru Takakusagi
- Institute for Catalysis, Hokkaido University, N21 W10, Kita-ku, Sapporo, Hokkaido, Japan
| | - Yasuhiro Iwasawa
- Innovation Research Center for Fuel Cells and Graduate School of Informatics and Engineering, The University of Electro-Communications, 1-5-1 Chofugaoka, Chofu, Tokyo, Japan
| | - Kiyotaka Asakura
- Institute for Catalysis, Hokkaido University, N21 W10, Kita-ku, Sapporo, Hokkaido, Japan
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Zhang Y, Liu Y, Meng Z, Ning C, Xiao C, Deng K, Jena P, Lu R. Confinement boosts CO oxidation on an Ni atom embedded inside boron nitride nanotubes. Phys Chem Chem Phys 2018; 20:17599-17605. [DOI: 10.1039/c8cp01957f] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Because of the confinement effect, Ni embedded on the interior surface of BNNT exhibits a much higher catalytic activity for CO oxidation by comparing with that embedded in h-BN or on the outside surface of BNNT.
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Affiliation(s)
- Yadong Zhang
- Department of Applied Physics
- Nanjing University of Science and Technology
- Nanjing 210094
- People's Republic of China
| | - Yuzhen Liu
- Department of Applied Physics
- Nanjing University of Science and Technology
- Nanjing 210094
- People's Republic of China
| | - Zhaoshun Meng
- Department of Applied Physics
- Nanjing University of Science and Technology
- Nanjing 210094
- People's Republic of China
| | - Cai Ning
- Department of Applied Physics
- Nanjing University of Science and Technology
- Nanjing 210094
- People's Republic of China
| | - Chuanyun Xiao
- Department of Applied Physics
- Nanjing University of Science and Technology
- Nanjing 210094
- People's Republic of China
| | - Kaiming Deng
- Department of Applied Physics
- Nanjing University of Science and Technology
- Nanjing 210094
- People's Republic of China
| | - Purusottam Jena
- Department of Physics
- Virginia Commonwealth University
- Richmond
- USA
| | - Ruifeng Lu
- Department of Applied Physics
- Nanjing University of Science and Technology
- Nanjing 210094
- People's Republic of China
- State Key Lab of Molecular Reaction Dynamics
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Yuan Q, Takakusagi S, Wakisaka Y, Uemura Y, Wada T, Ariga H, Asakura K. Polarization-dependent Total Reflection Fluorescence X-ray Absorption Fine Structure (PTRF-XAFS) Studies on the Structure of a Pt Monolayer on Au(111) Prepared by the Surface-limited Redox Replacement Reaction. CHEM LETT 2017. [DOI: 10.1246/cl.170423] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Qiuyi Yuan
- ICAT, Hokkaido University, Kita 21 Nishi 10, Kita-ku, Sapporo, Hokkaido 001-0021
| | - Satoru Takakusagi
- ICAT, Hokkaido University, Kita 21 Nishi 10, Kita-ku, Sapporo, Hokkaido 001-0021
| | - Yuki Wakisaka
- ICAT, Hokkaido University, Kita 21 Nishi 10, Kita-ku, Sapporo, Hokkaido 001-0021
| | - Yohei Uemura
- Institute for Molecular Science, Okazaki, Aichi 444-0867
| | | | - Hiroko Ariga
- ICAT, Hokkaido University, Kita 21 Nishi 10, Kita-ku, Sapporo, Hokkaido 001-0021
| | - Kiyotaka Asakura
- ICAT, Hokkaido University, Kita 21 Nishi 10, Kita-ku, Sapporo, Hokkaido 001-0021
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Mochizuki I, Ariga H, Fukaya Y, Wada K, Maekawa M, Kawasuso A, Shidara T, Asakura K, Hyodo T. Structure determination of the rutile-TiO2(110)-(1 × 2) surface using total-reflection high-energy positron diffraction (TRHEPD). Phys Chem Chem Phys 2016; 18:7085-92. [DOI: 10.1039/c5cp07892j] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Detailed structure of the rutile-TiO2(110)-(1 × 2) has been determined using the newly developed technique of total-reflection high-energy positron diffraction (TRHEPD).
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Affiliation(s)
- I. Mochizuki
- Institute of Materials Structure Science
- High Energy Accelerator Research Organization (KEK)
- Ibaraki 305-0801
- Japan
| | - H. Ariga
- Institute for Catalysis
- Hokkaido University
- Sapporo
- Japan
| | - Y. Fukaya
- Advanced Science Research Center
- Japan Atomic Energy Agency
- Naka
- Japan
| | - K. Wada
- Institute of Materials Structure Science
- High Energy Accelerator Research Organization (KEK)
- Ibaraki 305-0801
- Japan
| | - M. Maekawa
- Quantum Beam Science Directorate
- Japan Atomic Energy Agency
- Takasaki
- Japan
| | - A. Kawasuso
- Quantum Beam Science Directorate
- Japan Atomic Energy Agency
- Takasaki
- Japan
| | - T. Shidara
- Accelerator Laboratory
- High Energy Accelerator Research Organization (KEK)
- Tsukuba
- Japan
| | - K. Asakura
- Institute for Catalysis
- Hokkaido University
- Sapporo
- Japan
| | - T. Hyodo
- Institute of Materials Structure Science
- High Energy Accelerator Research Organization (KEK)
- Ibaraki 305-0801
- Japan
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Wu P, Du P, Zhang H, Cai C. Graphyne-supported single Fe atom catalysts for CO oxidation. Phys Chem Chem Phys 2015; 17:1441-9. [DOI: 10.1039/c4cp04181j] [Citation(s) in RCA: 119] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
We demonstrate that graphyne is a good substrate for single Fe atom catalysts, which have high catalytic activity for CO oxidation.
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Affiliation(s)
- Ping Wu
- Jiangsu Key Laboratory of New Power Batteries
- Jiangsu Collaborative Innovation Center of Biomedical Functional Materials
- College of Chemistry and Materials Science
- Nanjing Normal University
- Nanjing 210097
| | - Pan Du
- Jiangsu Key Laboratory of New Power Batteries
- Jiangsu Collaborative Innovation Center of Biomedical Functional Materials
- College of Chemistry and Materials Science
- Nanjing Normal University
- Nanjing 210097
| | - Hui Zhang
- Jiangsu Key Laboratory of New Power Batteries
- Jiangsu Collaborative Innovation Center of Biomedical Functional Materials
- College of Chemistry and Materials Science
- Nanjing Normal University
- Nanjing 210097
| | - Chenxin Cai
- Jiangsu Key Laboratory of New Power Batteries
- Jiangsu Collaborative Innovation Center of Biomedical Functional Materials
- College of Chemistry and Materials Science
- Nanjing Normal University
- Nanjing 210097
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