A general one-pot strategy for the synthesis of Au@multi-oxide yolk@shell nanospheres with enhanced catalytic performance

Abstract

By integrating redox self-assembly and redox etching processes, we report a general one-pot strategy for the synthesis of Au@multi-MxOy (M = Co, Ce, Fe, and Sn) yolk@shell nanospheres. Without any additional protecting molecule or reductant, the whole reaction is a clean redox process that happens among the inorganic metal salts in an alkaline aqueous solution. By using this method, Au@Co3O4/CeO2 (Au@Co-Ce), Au@Co3O4/Fe2O3 (Au@Co-Fe), and Au@CeO2/SnO2 (Au@Ce-Sn) yolk@shell nanospheres with binary oxides as shells, Au@Co3O4/CeO2/Fe2O3 (Au@Co-Ce-Fe) yolk@shell nanospheres with ternary oxides as shells and Au@Co3O4/CeO2/Fe2O3/SnO2 (Au@Co-Ce-Fe-Sn) yolk@shell nanospheres with quaternary oxides as shells can be obtained. Subsequently, the catalytic CO oxidation was selected as the catalytic model, and the Au@Co-Ce system was chosen as the catalyst. It was found that the catalytic activity of Au@Co-Ce yolk@shell nanospheres can be optimized by altering the relative proportion of Co and Ce oxides.