Atomically Dispersed Platinum Modulated by Sulfide as an Efficient Electrocatalyst for Hydrogen Evolution Reaction.

Catalytically active metals atomically dispersed on supports presents the ultimate atom utilization efficiency and cost-effective pathway for electrocatalyst design. Optimizing the coordination nature of metal atoms represents the advanced strategy for enhancing the catalytic activity and the selectivity of single-atom catalysts (SACs). Here, we designed a transition-metal based sulfide-NiS with abundant exposed Ni vacancies created by the interaction between chloride ions and the functional groups on the surface of Ni3S2 for the anchoring of atomically dispersed Pt (Pt-NiS). The theoretical calculation reveals that unique Pt-NiS support interaction increases the orbital electron occupation at the Fermi level and leads to a shift-down of the -band center, which energetically enhances HO adsorption and provides the optimum H binding sites. Introducing Pt into Ni position in NiS system can efficiently enhance electronic field distribution and construct a metallic-state feature on the Pt sites by the orbital hybridization between S-3p and Pt-5d for improved reaction kinetics. Finally, the fabricated Pt-NiS SAC is supported by Ag nanowires network to construct a seamless conductive three-dimensional (3D) nanostructure (Pt-NiS@Ag NWs), and the developed catalyst shows an extremely great mass activity of 7.6 A mg with 27-time higher than the commercial Pt/C HER catalyst.