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

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 d_(z2) orbital electronic structure,and then realize the depth upward shift of d-band center and enhance the adsorption of H*on Co sites.