Critical roles of surface oxygen vacancy in heterogeneous catalysis over ceria-based materials: A selected review

Surface oxygen vacancies, dynamically created and annihilated under the reaction conditions, may serve as a unique form of active site for heterogeneous catalysis. In this study, the mechanisms of selected reactions (i.e., CO oxidation, watergas shift, CO2 hydrogenation, alcohol carbonation, and selective catalytic reduction of NO with NH3) proposed by in-situ spectroscopy characterizations were reviewed to elucidate the critical roles of surface oxygen vacancies in heterogeneous catalysis over ceria-based materials. It is demonstrated that the surface oxygen vacancy may interact with reactants and intermediates through enhanced adsorption and activation to promote the overall catalysis. Operando spectroscopy studies that enable in-situ spectroscopy characterizations of surface oxygen vacancies and reaction intermediates coupled with simultaneous kinetic measurements are highly recommended to further advance the fundamental understanding of ceria catalysis. © 2021 The Chemical Society of Japan.