Activating sulfur sites of CoS2 electrocatalysts through tin doping for hydrogen evolution reaction

Exploring high efficient transition-metal dichalcogenides catalysts for hydrogen evolution reaction (HER) is important for water-derived hydrogen fuel. Pyrite cobalt disulfide (CoS 2 ) is one of the potential HER catalysts due to its low price and inherent metallicity, but its catalytic activity is still unsatisfactory possibly attributed to the S sites with catalytic inert; hydrogen adsorption on S sites is weak extremely. Metal cation doping has been considered as one of the most available methods to modulate the electronic structure of electrocatalysts. Here, we report non-transition metal tin (Sn) doped CoS 2 nanowire arrays grown on carbon cloth (Sn-CoS 2 /CC) as available catalysts for HER. The Sn-CoS 2 /CC catalyst with optimal doping concentration not only has an enhanced over potential of 161 mV at 10 mA cm −2 , and the Tafel slope is 94 mV dec -1 , but also shows good long-term durability in 32 h of testing. Experimental results and further density functional theory (DFT) calculations show that Sn doping can improve the charge transfer ability, enhance electronic conductivity, and arouse the catalytic insert S sites with optimal hydrogen adsorption free energy (ΔG H* ). This work investigates a new method to activate the inert sites in metal-compound catalysts for water splitting and beyond through non-transition metal doping.