Seamlessly conductive Co(OH) tailored atomically dispersed Pt electrocatalyst with a hierarchical nanostructure for an efficient hydrogen evolution reaction

Single-atom catalysts (SACs) have exhibited extraordinary catalytic performance due to the utmost atom utilization efficiency and unique electronic states via metal-support interactions. Rationally designing SACs at the atomic level by structural engineering is desirable for an efficient hydrogen evolution reaction (HER). Herein, single-atom Pt was anchored on two-dimensional (2D) Co(OH) 2 nanosheets growing on Ag nanowires (Pt SA -Co(OH) 2 @Ag NW) to construct a seamlessly conductive network hybrid catalyst via electrochemical phase transformation from metallic Co@Ag NW. The Ag NW network provides a continuous electron transport pathway through metal active sites, contributing to an extremely low charge transfer resistance ( R ct , 0.7 Ω), and the hierarchical nanostructure has a large electrochemical surface area for high atom utilization efficiency and rich mass transport pathways for hydrogen generation and release. Moreover, Co(OH) 2 tailored Pt sites induce a local tip-enhancement electric field region around the Pt site and more d contribution for boosting H adsorption and H 2 O adsorption. Thus, the synthesized Pt SA -Co(OH) 2 @Ag NW catalyst shows outstanding HER activity with only 29 mV overpotential in 1.0 M KOH at 10 mA cm −2 and 22.5-fold higher mass activity than the commercial Pt/C catalyst. A hybrid catalyst based on single-atom Pt anchored Co(OH) 2 nanosheets growing on a Ag nanowire network with high intrinsic activity is developed for an efficient hydrogen evolution reaction.