One-pot synthesis of Au@Pt star-like nanocrystals and their enhanced electrocatalytic performance for formic acid and ethanol oxidation

The current bottleneck facing further developments in fuel cells is the lack of durable electrocatalysts with satisfactory activity. In this study, a simple and fast one-pot wet-chemical method is proposed to synthesize novel Au@Pt star-like bimetallic nanocrystals (Au@Pt SLNCs) with a low Pt/Au ratio of 1:4, which show great electrocatalytic properties and outstanding stability toward the electro-oxidation reactions commonly found in fuel cells. The star-like Au core (90 ± 20 nm) is partially coated with 5 nm Pt nanocluster shells, a morphology which creates a large amount of boundaries and edges, thus tuning the surface electronic structure as demonstrated by X-ray photoelectron spectroscopy and CO-stripping measurements. This promotes excellent electrocatalytic performance towards the formic acid oxidation reaction in acidic media and the ethanol oxidation reaction in alkaline media, compared to commercial Pt or Au@Pt triangular nanoprisms, in which the Au core is fully coated by a Pt shell. Au@Pt SLNCs have the highest current density within the dehydrogenation potential range, needing the least potential to achieve a certain current density as well as the highest long-term stability. Because of the small amount of Pt usage, very fast synthesis, excellent electrocatalytic activity and durability, the proposed Au@Pt SLNCs have a promising practical application in fuel cells.