Spectroscopic insights into gold-cerium oxidation states influencing catalytic activity and selectivity in CeO2-supported gold during CO-PROX reaction

Abstract

Here we present an investigation into the evolution of gold-cerium oxidation states in Au/CeO2 catalysts concerning Au content and its relationship between the influence of these oxidation states on catalytic activity and selectivity during the CO-PROX reaction. The Au-loading notably influences the electronic states of gold and cerium species. As gold content increases, metallic gold particles form, and their stability under reaction conditions decreases. Oxygen vacancies and dynamic oxygen storage capacity (OSC) increase at low gold loadings (0.32 wt.%). Catalytic activity depends on Au content, exhibiting higher CO2 selectivity at lower Au content (0.32 wt.%) under 120 °C. CO oxidation activity heavily depends on dynamic OSC, which is associated with oxygen vacancies. Selectivity depends on the specific electronic properties of catalysts. CO2 selectivity depends on the presence of cationic Au species. Meanwhile, H2 oxidation occurs on surfaces where a high content of metallic Au species is exposed on the catalyst surface.