Modulation of d‐orbital to realize enriched electronic cobalt sites in cobalt sulfide for enhanced hydrogen evolution in electrocatalytic water/seawater splitting

Abstract Herein, a novel single‐atomic Pt doping and interface‐rich CoS/Co(OH) 2 (Pt‐CoS/Co(OH) 2 /C) electrocatalyst has been successfully prepared. Benefiting from precise regulation of d‐orbital electronic structure modulation on Co site, Pt‐CoS/Co(OH) 2 /C exhibited remarkable HER activity and high stability for hydrogen evolution in splitting both water (73 mV@10 mA·cm −2 ) and seawater (87 mV@10 mA·cm −2 ). Notably, atomic Pt doping was introduced into CoS/Co(OH) 2 , which could produce local unbalanced Coulombic force and significantly increased the number of S vacancies, and then expose abundant Co sites. Meantime, Co(OH) 2 in Pt‐CoS/Co(OH) 2 /C could act as the adsorption sites for H 2 O in hydrogen evolution reaction process. Density functional theory results also proved that atomic Pt doping, S vacancies and Co(OH) 2 coupling could result in the formation of enriched electronic Co sites and optimize orbital electronic structure, and then realize the depth upward shift of d‐band center and enhance the adsorption of H* on Co sites.