Visible light-assisted thermal catalytic reverse water gas reaction over Cu-CeO2: The synergistic of hot electrons and oxygen vacancies induced by LSPR effect

Abstract

The construction of a light-assisted thermal catalytic system has great potential in the reverse water gas shift reaction (RWGS). To explore the role of light in the thermo-catalytic system, a prepared Cu-CeO2 sample was performed for the RWGS reaction under visible light irradiation. It was found that Cu-CeO2 sample shows an excellent RWGS catalytic activity and CO selectivity, and the production of CO with light introduction has been significantly increased by 30 % at 250 °C. A combination of In-situ DRIFTS, Quasi-situ EPR, and XPS characterization results demonstrate that under visible light irradiation, the localized surface plasmon resonance (LSPR) produced by Cu nanoparticles stimulates hot electrons transfer and attack to the bidentate formats and linear-CO intermediate species, resulting in that accelerating the decomposition and desorption of intermediate species into CO, but inhibiting further reduction of CO. Moreover, the spillover of H2 from Cu to CeO2 surface is also affected by light due to the observed regeneration of oxygen vacancies on the CeO2 surface, which together influence the yield of CO. This work shows that introducing visible light could improve RWGS reaction activity and retain the selectivity of CO, which maybe provide a new approach to control the product selectivity for a thermal catalytic reaction.