Selective immobilization of single-atom Au on cerium dioxide for low-temperature removal of C1 gaseous contaminants

Abstract

Selective immobilization of single-atom Au on the specific facets of CeO2 has been successfully performed by redox etching precipitation (REP), which makes it possible to clearly refine the interfacial effect of multiple-facet support on single atom. With systemic characterizations, it is found that single-atom Au is apt to lie on nonpolar facets of CeO2 (111) and (110) rather than polar facet of CeO2 (100). The modification of morphology-dependent properties is attributed to the different interaction between Au atom and each CeO2 interface. Because of synergy between Au and CeO2, more oxygen vacancies and more active oxygen species are generated; meanwhile, the interfacial effect stabilizes the charged Au species which serves as active site. Therefore, the performance in catalytic oxidation of HCHO and CO on CeO2 is facilitated by loading Au. Among them, CeO2 rod-supported Au as an optimal catalyst exhibits a remarkable activity and stability. With in-situ characterization, the reaction mechanisms for HCHO and CO oxidation over Au/r-CeO2 are studied. Meanwhile, it is proved that REP strategy is also valid to obviously promote catalytic performance whenever commercial CeO2 is used or Au is replaced with Ag, so the improvement of recently applied catalyst with REP process is promising.