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Oropeza FE, Dzade NY, Pons-Martí A, Yang Z, Zhang KHL, de Leeuw NH, Hensen EJM, Hofmann JP. Electronic Structure and Interface Energetics of CuBi 2O 4 Photoelectrodes. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2020; 124:22416-22425. [PMID: 33193938 PMCID: PMC7659311 DOI: 10.1021/acs.jpcc.0c08455] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Indexed: 05/03/2023]
Abstract
CuBi2O4 exhibits significant potential for the photoelectrochemical (PEC) conversion of solar energy into chemical fuels, owing to its extended visible-light absorption and positive flat band potential vs the reversible hydrogen electrode. A detailed understanding of the fundamental electronic structure and its correlation with PEC activity is of significant importance to address limiting factors, such as poor charge carrier mobility and stability under PEC conditions. In this study, the electronic structure of CuBi2O4 has been studied by a combination of hard X-ray photoemission spectroscopy, resonant photoemission spectroscopy, and X-ray absorption spectroscopy (XAS) and compared with density functional theory (DFT) calculations. The photoemission study indicates that there is a strong Bi 6s-O 2p hybrid electronic state at 2.3 eV below the Fermi level, whereas the valence band maximum (VBM) has a predominant Cu 3d-O 2p hybrid character. XAS at the O K-edge supported by DFT calculations provides a good description of the conduction band, indicating that the conduction band minimum is composed of unoccupied Cu 3d-O 2p states. The combined experimental and theoretical results suggest that the low charge carrier mobility for CuBi2O4 derives from an intrinsic charge localization at the VBM. Also, the low-energy visible-light absorption in CuBi2O4 may result from a direct but forbidden Cu d-d electronic transition, leading to a low absorption coefficient. Additionally, the ionization potential of CuBi2O4 is higher than that of the related binary oxide CuO or that of NiO, which is commonly used as a hole transport/extraction layer in photoelectrodes. This work provides a solid electronic basis for topical materials science approaches to increase the charge transport and improve the photoelectrochemical properties of CuBi2O4-based photoelectrodes.
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Affiliation(s)
- Freddy E. Oropeza
- Laboratory
of Inorganic Materials and Catalysis, Department of Chemical Engineering
and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
- IMDEA
Energy Institute, Avenida
Ramón de la Sagra, 3, 28935 Móstoles, MadridSpain
- F.E.O.
| | - Nelson Y. Dzade
- School
of Chemistry, Cardiff University, Main Building, Park Place, CF10 3AT Cardiff, U.K.
| | - Amalia Pons-Martí
- Laboratory
of Inorganic Materials and Catalysis, Department of Chemical Engineering
and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - Zhenni Yang
- State
Key Laboratory of Physical Chemistry of Solid Surfaces, College of
Chemistry and Chemical Engineering, Xiamen
University, Xiamen 361005, P.R. China
| | - Kelvin H. L. Zhang
- State
Key Laboratory of Physical Chemistry of Solid Surfaces, College of
Chemistry and Chemical Engineering, Xiamen
University, Xiamen 361005, P.R. China
| | - Nora H. de Leeuw
- School
of Chemistry, Cardiff University, Main Building, Park Place, CF10 3AT Cardiff, U.K.
- School
of Chemistry, University of Leeds, Leeds LS2 9JT, U.K.
- Department
of Earth Sciences, Utrecht University, Princetonlaan 8a, 3584 CB Utrecht, The Netherlands
| | - Emiel J. M. Hensen
- Laboratory
of Inorganic Materials and Catalysis, Department of Chemical Engineering
and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - Jan P. Hofmann
- Laboratory
of Inorganic Materials and Catalysis, Department of Chemical Engineering
and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
- Surface Science
Laboratory, Department of Materials and Earth Sciences, Technical University of Darmstadt, Otto-Berndt-Strasse 3, 64287 Darmstadt, Germany
- J.P.H.
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Moreno-López JC, Fedi F, Argentero G, Carini M, Chimborazo J, Meyer J, Pichler T, Mateo-Alonso A, Ayala P. Exclusive Substitutional Nitrogen Doping on Graphene Decoupled from an Insulating Substrate. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2020; 124:22150-22157. [PMID: 33072238 PMCID: PMC7552092 DOI: 10.1021/acs.jpcc.0c06415] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 08/31/2020] [Indexed: 06/01/2023]
Abstract
The on-surface synthesis of atomically flat N-doped graphene on oxidized copper is presented. Besides circumventing the almost standard use of metallic substrates for growth, this method allows producing graphene with ∼2.0 at % N in a substitutional configuration directly decoupled from the substrate. Angle-resolved photoemission shows a linear energy-momentum dispersion where the Dirac point lies at the Fermi level. Additionally, the N functional centers can be selectively tailored in sp2 substitutional configuration by making use of a purpose-made molecular precursor: dicyanopyrazophenanthroline (C16H6N6).
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Affiliation(s)
| | - Filippo Fedi
- Faculty
of Physics, University of Vienna, 1090 Wien, Austria
| | | | - Marco Carini
- POLYMAT,
University of the Basque Country UPV/EHU, Avenida de Tolosa 72, E-20018 Donostia-San Sebastian, Spain
| | | | - Jannik Meyer
- Faculty
of Physics, University of Vienna, 1090 Wien, Austria
| | - Thomas Pichler
- Faculty
of Physics, University of Vienna, 1090 Wien, Austria
| | - Aurelio Mateo-Alonso
- Faculty
of Physics, University of Vienna, 1090 Wien, Austria
- Ikerbasque,
Basque Foundation for Science, 48013 Bilbao, Spain
| | - Paola Ayala
- Faculty
of Physics, University of Vienna, 1090 Wien, Austria
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Yang F, Sun Q, Ma LL, Jia Y, Luo SJ, Liu JM, Geng WT, Chen JY, Li S, Yu Y. Magnetic Properties of CumOn Clusters: A First Principles Study. J Phys Chem A 2010; 114:8417-22. [DOI: 10.1021/jp103703n] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Fan Yang
- Institute of Nanoscience and Nanotechnology, Huazhong Normal University, Wuhan 430079, China, School of Physics and Engineering, Zhengzhou University, Zhengzhou 450001, China, Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China, Materials Modeling Laboratory, University of Science and Technology Beijing, Beijing 100083, China, School of Environment and Civil Engineering, Wuhan Institute of Technology, Wuhan 430073, China, and Department of Physics, Virginia Commonwealth
| | - Qiang Sun
- Institute of Nanoscience and Nanotechnology, Huazhong Normal University, Wuhan 430079, China, School of Physics and Engineering, Zhengzhou University, Zhengzhou 450001, China, Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China, Materials Modeling Laboratory, University of Science and Technology Beijing, Beijing 100083, China, School of Environment and Civil Engineering, Wuhan Institute of Technology, Wuhan 430073, China, and Department of Physics, Virginia Commonwealth
| | - L. L. Ma
- Institute of Nanoscience and Nanotechnology, Huazhong Normal University, Wuhan 430079, China, School of Physics and Engineering, Zhengzhou University, Zhengzhou 450001, China, Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China, Materials Modeling Laboratory, University of Science and Technology Beijing, Beijing 100083, China, School of Environment and Civil Engineering, Wuhan Institute of Technology, Wuhan 430073, China, and Department of Physics, Virginia Commonwealth
| | - Yu Jia
- Institute of Nanoscience and Nanotechnology, Huazhong Normal University, Wuhan 430079, China, School of Physics and Engineering, Zhengzhou University, Zhengzhou 450001, China, Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China, Materials Modeling Laboratory, University of Science and Technology Beijing, Beijing 100083, China, School of Environment and Civil Engineering, Wuhan Institute of Technology, Wuhan 430073, China, and Department of Physics, Virginia Commonwealth
| | - S. J. Luo
- Institute of Nanoscience and Nanotechnology, Huazhong Normal University, Wuhan 430079, China, School of Physics and Engineering, Zhengzhou University, Zhengzhou 450001, China, Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China, Materials Modeling Laboratory, University of Science and Technology Beijing, Beijing 100083, China, School of Environment and Civil Engineering, Wuhan Institute of Technology, Wuhan 430073, China, and Department of Physics, Virginia Commonwealth
| | - J. M. Liu
- Institute of Nanoscience and Nanotechnology, Huazhong Normal University, Wuhan 430079, China, School of Physics and Engineering, Zhengzhou University, Zhengzhou 450001, China, Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China, Materials Modeling Laboratory, University of Science and Technology Beijing, Beijing 100083, China, School of Environment and Civil Engineering, Wuhan Institute of Technology, Wuhan 430073, China, and Department of Physics, Virginia Commonwealth
| | - W. T. Geng
- Institute of Nanoscience and Nanotechnology, Huazhong Normal University, Wuhan 430079, China, School of Physics and Engineering, Zhengzhou University, Zhengzhou 450001, China, Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China, Materials Modeling Laboratory, University of Science and Technology Beijing, Beijing 100083, China, School of Environment and Civil Engineering, Wuhan Institute of Technology, Wuhan 430073, China, and Department of Physics, Virginia Commonwealth
| | - J. Y. Chen
- Institute of Nanoscience and Nanotechnology, Huazhong Normal University, Wuhan 430079, China, School of Physics and Engineering, Zhengzhou University, Zhengzhou 450001, China, Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China, Materials Modeling Laboratory, University of Science and Technology Beijing, Beijing 100083, China, School of Environment and Civil Engineering, Wuhan Institute of Technology, Wuhan 430073, China, and Department of Physics, Virginia Commonwealth
| | - Sa Li
- Institute of Nanoscience and Nanotechnology, Huazhong Normal University, Wuhan 430079, China, School of Physics and Engineering, Zhengzhou University, Zhengzhou 450001, China, Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China, Materials Modeling Laboratory, University of Science and Technology Beijing, Beijing 100083, China, School of Environment and Civil Engineering, Wuhan Institute of Technology, Wuhan 430073, China, and Department of Physics, Virginia Commonwealth
| | - Ying Yu
- Institute of Nanoscience and Nanotechnology, Huazhong Normal University, Wuhan 430079, China, School of Physics and Engineering, Zhengzhou University, Zhengzhou 450001, China, Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China, Materials Modeling Laboratory, University of Science and Technology Beijing, Beijing 100083, China, School of Environment and Civil Engineering, Wuhan Institute of Technology, Wuhan 430073, China, and Department of Physics, Virginia Commonwealth
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