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Banti A, Zafeiridou C, Charalampakis M, Spyridou ON, Georgieva J, Binas V, Mitrousi E, Sotiropoulos S. IrO 2 Oxygen Evolution Catalysts Prepared by an Optimized Photodeposition Process on TiO 2 Substrates. Molecules 2024; 29:2392. [PMID: 38792253 PMCID: PMC11124129 DOI: 10.3390/molecules29102392] [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: 04/14/2024] [Revised: 05/05/2024] [Accepted: 05/16/2024] [Indexed: 05/26/2024] Open
Abstract
Preparing high-performance oxygen evolution reaction (OER) catalysts with low precious metal loadings for water electrolysis applications (e.g., for green hydrogen production) is challenging and requires electrically conductive, high-surface-area, and stable support materials. Combining the properties of stable TiO2 with those of active iridium oxide, we synthesized highly active electrodes for OER in acidic media. TiO2 powders (both commercially available Degussa P-25® and hydrothermally prepared in the laboratory from TiOSO4, either as received/prepared or following ammonolysis to be converted to titania black), were decorated with IrO2 by UV photodeposition from Ir(III) aqueous solutions of varied methanol scavenger concentrations. TEM, EDS, FESEM, XPS, and XRD measurements demonstrate that the optimized version of the photodeposition preparation method (i.e., with no added methanol) leads to direct deposition of well-dispersed IrO2 nanoparticles. The electroactive surface area and electrocatalytic performance towards OER of these catalysts have been evaluated by cyclic voltammetry (CV), Linear Sweep Voltammetry (LSV), and Electrochemical Impedance Spectroscopy (EIS) in 0.1 M HClO4 solutions. All TiO2-based catalysts exhibited better mass-specific (as well as intrinsic) OER activity than commercial unsupported IrO2, with the best of them (IrO2 on Degussa P-25® ΤiO2 and laboratory-made TiO2 black) showing 100 mAmgIr-1 at an overpotential of η = 243 mV. Chronoamperometry (CA) experiments also proved good medium-term stability of the optimum IrO2/TiO2 electrodes during OER.
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Affiliation(s)
- Angeliki Banti
- Physical Chemistry Laboratory, Department of Chemistry, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece; (C.Z.); (O.-N.S.); (V.B.); (E.M.)
| | - Christina Zafeiridou
- Physical Chemistry Laboratory, Department of Chemistry, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece; (C.Z.); (O.-N.S.); (V.B.); (E.M.)
| | - Michail Charalampakis
- Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas (FORTH-IESL), 70013 Herakleion, Greece;
| | - Olga-Niki Spyridou
- Physical Chemistry Laboratory, Department of Chemistry, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece; (C.Z.); (O.-N.S.); (V.B.); (E.M.)
| | - Jenia Georgieva
- Rostislaw Kaischew Institute of Physical Chemistry, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria;
| | - Vasileios Binas
- Physical Chemistry Laboratory, Department of Chemistry, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece; (C.Z.); (O.-N.S.); (V.B.); (E.M.)
- Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas (FORTH-IESL), 70013 Herakleion, Greece;
| | - Efrosyni Mitrousi
- Physical Chemistry Laboratory, Department of Chemistry, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece; (C.Z.); (O.-N.S.); (V.B.); (E.M.)
| | - Sotiris Sotiropoulos
- Physical Chemistry Laboratory, Department of Chemistry, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece; (C.Z.); (O.-N.S.); (V.B.); (E.M.)
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Ma H, Jiao Y, Guo W, Liu X, Li Y, Wen X. Machine learning predicts atomistic structures of multielement solid surfaces for heterogeneous catalysts in variable environments. Innovation (N Y) 2024; 5:100571. [PMID: 38379790 PMCID: PMC10878119 DOI: 10.1016/j.xinn.2024.100571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 01/02/2024] [Indexed: 02/22/2024] Open
Abstract
Solid surfaces usually reach thermodynamic equilibrium through particle exchange with their environment under reactive conditions. A prerequisite for understanding their functionalities is detailed knowledge of the surface composition and atomistic geometry under working conditions. Owing to the large number of possible Miller indices and terminations involved in multielement solids, extensive sampling of the compositional and conformational space needed for reliable surface energy estimation is beyond the scope of ab initio calculations. Here, we demonstrate, using the case of iron carbides in environments with varied carbon chemical potentials, that the stable surface composition and geometry of multielement solids under reactive conditions, which involve large compositional and conformational spaces, can be predicted at ab initio accuracy using an approach that combines the bond valence model, Gaussian process regression, and ab initio thermodynamics. Determining the atomistic structure of surfaces under working conditions paves the way toward identifying the true active sites of multielement catalysts in heterogeneous catalysis.
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Affiliation(s)
- Huan Ma
- State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- National Energy Center for Coal to Liquids, Synfuels China Co., Ltd., Beijing 101400, China
| | - Yueyue Jiao
- State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- National Energy Center for Coal to Liquids, Synfuels China Co., Ltd., Beijing 101400, China
| | - Wenping Guo
- National Energy Center for Coal to Liquids, Synfuels China Co., Ltd., Beijing 101400, China
| | - Xingchen Liu
- State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yongwang Li
- State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- National Energy Center for Coal to Liquids, Synfuels China Co., Ltd., Beijing 101400, China
- Beijing Advanced Innovation Center for Materials Genome Engineering, Industry−University Cooperation Base between Beijing Information S&T University and Synfuels China Co., Ltd., Beijing 100101, China
| | - Xiaodong Wen
- State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- National Energy Center for Coal to Liquids, Synfuels China Co., Ltd., Beijing 101400, China
- Beijing Advanced Innovation Center for Materials Genome Engineering, Industry−University Cooperation Base between Beijing Information S&T University and Synfuels China Co., Ltd., Beijing 100101, China
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Li H, Reuter K. Ab Initio Thermodynamic Stability of Carbide Catalysts under Electrochemical Conditions. ACS Catal 2022. [DOI: 10.1021/acscatal.2c01732] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Haobo Li
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
- Chair for Theoretical Chemistry and Catalysis Research Center, Technische Universität München, Lichtenbergstr. 4, 85747 Garching, Germany
| | - Karsten Reuter
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
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