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Kajino T, Sugimoto R, Ueda T, Fukuura S, Yumura T, Haneda M, Hosokawa S. Experimental and Computational Insights into the Catalytic Mechanism of Y 1-xBa xCoO 3-δ Perovskite Oxides with a Controlled Crystal Structure. Inorg Chem 2024; 63:10980-10986. [PMID: 38815988 DOI: 10.1021/acs.inorgchem.4c00136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2024]
Abstract
The crystal structure of Co-based perovskite oxides (ACoO3) can be controlled by adjusting the A-site elements. In this study, we synthesized Y1-xBaxCoO3-δ (x = 0, 0.5, and 1.0) via a coprecipitation method and investigated their CO oxidation performances. YCoO3 (x = 0; cubic perovskite oxide; Pbnm) shows a higher catalytic performance than Y0.5Ba0.5CoO2.72 (x = 0.5; A-site-ordered double perovskite oxide; P4/nmm), which exhibits high oxygen nonstoichiometric properties, and BaCoO3 (x = 1.0; hexagonal perovskite oxide; P63/mmc), which contains high-valent Co4+ species. To elucidate the reaction mechanism, we conducted isotopic experiments with CO and 18O2. The CO oxidation reaction on YCoO3 proceeds via the Langmuir-Hinshelwood mechanism, which is a surface reaction of CO and O2 gas that does not utilize lattice oxygen. Because of the significantly smaller specific surface area of YCoO3 compared with that of the reference Pt/Al2O3, the bulk features of the crystal structures affect the catalytic reaction. When density functional theory is applied, YCoO3 clearly exhibits semiconducting properties in the ground state with the diamagnetic t2g6eg0 states, which can translate to a magnetic t2g5eg1 configuration upon excitation by a relatively low energy of 0.64 eV. We propose that the unique nature of YCoO3 activates oxygen in the gas phase, thereby enabling the smooth oxidation of CO. This study demonstrates that the bulk properties originating from the crystal structure contribute to the catalytic activity and reaction mechanism.
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Affiliation(s)
- Takanobu Kajino
- Faculty of Materials Science and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
- Advanced Research and Innovation Center, Denso Corporation, Nisshin, Aichi 470-0111, Japan
| | - Ryosuke Sugimoto
- Faculty of Materials Science and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Taisei Ueda
- Faculty of Materials Science and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Shuta Fukuura
- Faculty of Materials Science and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Takashi Yumura
- Faculty of Materials Science and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Masaaki Haneda
- Advanced Ceramics Research Center, Nagoya Institute of Technology, 10-6-29 Asahigaoka, Tajimi, Gifu 507-0071, Japan
| | - Saburo Hosokawa
- Faculty of Materials Science and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
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Hesse F, da Silva I, Bos JWG. Oxygen Migration Pathways in Layered LnBaCo 2O 6-δ (Ln = La - Y) Perovskites. JACS AU 2024; 4:1538-1549. [PMID: 38665656 PMCID: PMC11040552 DOI: 10.1021/jacsau.4c00049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 02/26/2024] [Accepted: 03/19/2024] [Indexed: 04/28/2024]
Abstract
Layered LnBaCo2O6-δ perovskites are important mixed ionic-electronic conductors, exhibiting outstanding catalytic properties for the oxygen evolution/reduction reaction. These phases exhibit considerable structural complexity, in particular, near room temperature, where a number of oxygen vacancy ordered superstructures are found. This study uses bond valence site energy calculations to demonstrate the key underlying structural features that favor facile ionic migration. BVSE calculations show that the 1D vacancy ordering for Ln = Sm-Tb could be beneficial at low temperatures as new pathways with reduced barriers emerge. By contrast, the 2D vacancy ordering for Ln = Dy and Y is not beneficial for ionic transport with the basic layered parent material having lower migration barriers. Overall, the key criterion for low migration barriers is an expanded ab plane, supported by Ba, coupled to a small Ln size. Hence, Ln = Y should be the best composition, but this is stymied by the low temperature 2D vacancy ordering and moderate temperature stability. The evolution of the oxygen cycling capability of these materials is also reported.
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Affiliation(s)
- Fabian Hesse
- Institute
of Chemical Sciences, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, U.K.
| | - Ivan da Silva
- ISIS
Facility, Rutherford Appleton Laboratory, Harwell Oxford, Didcot OX11 0QX, U.K.
| | - Jan-Willem G. Bos
- EaStCHEM
School of Chemistry, University of St Andrews, North Haugh, St Andrews KY16 9ST, U.K.
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Zhang W, Yashima M. Recent developments in oxide ion conductors: focusing on Dion-Jacobson phases. Chem Commun (Camb) 2022; 59:134-152. [PMID: 36510789 DOI: 10.1039/d2cc05288a] [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]
Abstract
Oxide-ion conductors, also known as "oxygen ion conductors," have garnered significant attention in recent years due to their extensive applications in a variety of electrochemical devices, including oxygen concentrators, solid-oxide fuel cells (SOFCs), and solid oxide electrolysis cells. The key to improving the performance of these devices is the creation of novel oxide-ion conductors. In this feature article, we discuss the recent developments of new structural families of oxide-ion conductors and of the Dion-Jacobson-type layered oxide-ion conductors with a particular emphasis on CsM2Ti2NbO10-δ (M = Bi and lanthanoids; δ represents oxygen-vacancy content) and their solid solutions. CsBi2Ti2NbO10-δ is the first example of an oxide-ion conductor with a Dion-Jacobson-type layered perovskite structure, and the structural characteristics of these materials are extracted here. We have proposed an original concept that the large sized Cs+ cations and M3+ displacements yield the large bottlenecks for oxide-ion migration, which would facilitate the discovery of novel oxide-ion conductors. This article presents evidence that Dion-Jacobson-type layered perovskites are superior oxide-ion conductors. We also demonstrate how the information gleaned from these studies can be applied to the design of novel oxide-ion conductors.
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Affiliation(s)
- Wenrui Zhang
- Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1 W4-17 O-okayama, Meguro-ku, Tokyo, 152-8551, Japan.
| | - Masatomo Yashima
- Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1 W4-17 O-okayama, Meguro-ku, Tokyo, 152-8551, Japan.
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