Minjae Kim, JeongHyun Cho, Kyung Tae Park, Chang Houn Rhee, Hai Woong Park, Ji Chul Jung
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引用次数: 0
Abstract
This study compares the catalytic activity of CO oxidation over two perovskite catalysts: stoichiometric LaCoO and non-stoichiometric LaCoO. Through catalytic activity and kinetic analysis, we aim to propose a strategy for designing efficient non-stoichiometric perovskite catalysts. The non-stoichiometric LaCoO catalyst exhibits superior activity in CO oxidation compared to the stoichiometric LaCoO catalyst. X-ray photoelectron spectroscopy (XPS) and Oxygen-temperature programmed desorption (O-TPD) results reveal an enrichment of adsorbed oxygen species, which are crucial for CO oxidation reactions, on the surface of non-stoichiometric LaCoO. This suggests that non-stoichiometric composition effectively generates oxygen vacancies on the catalyst surface, facilitating the formation of adsorbed oxygen species. Interestingly, a higher apparent activation energy is observed for the LaCoO compared to the LaCoO, while the reaction orders of CO are 1.0 and − 1.5 for the LaCoO and the LaCoO, respectively. Based on these findings, we conclude that the LaCoO follows the Mars-van Krevelen mechanism, utilizing lattice oxygen at high temperatures, while the LaCoO operates via the Langmuir-Hinshelwood mechanism at lower temperatures due to its enriched adsorbed oxygen species. This underscores non-stoichiometry as an efficient catalyst design strategy for enhancing catalytic activity of perovskites in various oxidation reactions where adsorbed oxygen species play a crucial role.
期刊介绍:
Journal of Industrial and Engineering Chemistry is published monthly in English by the Korean Society of Industrial and Engineering Chemistry. JIEC brings together multidisciplinary interests in one journal and is to disseminate information on all aspects of research and development in industrial and engineering chemistry. Contributions in the form of research articles, short communications, notes and reviews are considered for publication. The editors welcome original contributions that have not been and are not to be published elsewhere. Instruction to authors and a manuscript submissions form are printed at the end of each issue. Bulk reprints of individual articles can be ordered. This publication is partially supported by Korea Research Foundation and the Korean Federation of Science and Technology Societies.