Seamlessly conductive Co(OH)2tailored 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 statesviametal-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 catalystviaelectrochemical 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 omega), 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 H2O 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.