A New Core/Shell NiAu/Au Nanoparticle Catalyst with Pt-like Activity for Hydrogen Evolution Reaction

We report a general approach to NiAu alloy nanoparticles (NPs) by co-reduction of Ni(acac)(2) (acac = acetylacetonate) and HAuCl4 center dot 3H(2)O at 220 degrees C in the presence of oleylamine and oleic acid. Subject to potential cycling between 0.6 and 1.0 V, (vs reversible hydrogen electrode) in 0.5 M H2SO4, the NiAu NPs are transformed into core/shell NiAu/Au NPs that show much enhanced catalysis for hydrogen evolution reaction (HER) with Pt-like activity and much robust durability. The first-principles calculations suggest that the high activity arises from the formation of Au sites with low coordination numbers around the shell. Our synthesis is not limited to NiAu but can be extended to FeAu and CoAu as well, providing a general approach to MAu/Au NPs as a class of new = catalyst superior to Pt for water splitting and hydrogen generation.