A comparative investigation of electrocatalysis at Pt monolayers on shape-controlled Au nanocrystals: facet effect versus strain effect

Abstract

In order to explore how and to what extent differently shaped Au nanocrystals (NCs) as the cores may affect the electrocatalytic properties of the resulting Au@Pt catalysts; a monolayer (ML) of Pt was deposited on cubic, octahedral and rhombic dodecahedral Au nanocrystals by using the well-established galvanic redox replacement method. The as-obtained Au-NCs@Pt-ML catalysts exhibited strongly inhibited CO_ad oxidation in acidic media and a significantly enhanced ethanol oxidation reaction (EOR) in alkaline media as compared to commercial Pt/C, with an Au-shape dependent activity sequence in line with that of Pt single crystals of the corresponding orientations. Strain and facet effects were found to be jointly involved in determining the overall electrocatalytic activities at the three Au-NCs@Pt-ML catalysts, with the facet effect superimposed on the more pronounced strain effect.