Selective Surface Engineering of Heterogeneous Nanostructures: In Situ Unraveling of the Catalytic Mechanism on Pt–Au Catalyst

Heterogeneous nanostructures hold substantial promise in many fields including energy conversion and catalysis, and their functionality is largely determined by the interactive surface features of respective architectural components. Herein, we report the facile preparation of a Pt–Au heterogeneous nanostructure, which as a model exhibits not only the enhanced electrocatalysis for oxygen reduction reaction (ORR) and ethanol oxidation reaction (EOR), but also an unprecedented activity for formic acid oxidation (FAO). Further, selective under-potential deposition coupled with CO adsorption is employed to probe the electrocatalytic mechanism of the Pt–Au heterogeneous nanostructure. The electronic effect is clarified for the ORR and EOR mechanisms on the Pt–Au nanostructure. A synergetic mechanism in that Pt ruptures the C–H bond of HCOOH and Au converts the resulted −COOH into CO2 is revealed for FAO. This strategy provides a versatile and powerful tool for the selective surface engineering and in-depth analysis of the functionalizing mechanism of heterogeneous nanostructures.