Co-promotion of two-type active sites: PtCux single-atom alloy and copper-ceria interface for preferential oxidation of CO

Abstract

Isolated single atoms of a platinum-group dispersed in surface layer of a metal host to synthesize single-atom alloys (SAAs) has proven to be favorable for improving catalytic activity and while retaining high selectivity of host metal. Here we report a co-promotion strategy of PtCux single-atom alloy and copper-ceria interface for preferential oxidation of CO. The Pt0.1Cu0.19/CeO2 catalyst exhibits superior catalytic performance and excellent stability, attributable to the regulation of the electronic interaction between Pt and Cu as well as the high proportion of oxygen vacancies. Moreover, operando DRIFTS experiments prove that the partial of Cu0 on the surface of CeO2 is oxidized to Cu+ during catalysis. The adsorbed CO readily reacts with oxygen over the Pt0.1Cu0.19/CeO2 to produce CO2 due to the presence of two-type active sites. Density functional theory simulations in conjunction with isotopic experiments unequivocally reveal that the Mars-van Krevelen mechanism is prominent on the as-synthesized PtCu SAAs.