Competitive‐Reduction Chemistry on Ni‐Doped FeS2 Catalyst Reinforcing Acid‐Corrosion Resistance for Stable Hydrogen Evolution Reactions

Abstract

Transition‐metal chalcogenides are promising low‐cost hydrogen evolution reaction (HER) catalysts; however, they suffer from serious electrochemical corrosion in acidic environment. Herein, it is proposed that Ni‐doped FeS2 nanowire arrays (Ni‐FeS2 NWs) fabricated through a simple doping strategy show significantly enhanced antiacid stability during HER process relative to its FeS2 counterpart enabled by a S‐site competitive‐reduction chemistry. Transition‐state energy calculations indicate that Ni‐FeS2 and FeS2 show different HER catalytic active center at S and Fe sites, respectively. For Ni‐FeS2, this means more H+ preferentially adsorb on S sites for enhanced HER which simultaneously suppresses the competitive reduction of acid corrosion of FeS2 occurred at the same S sites. However, for FeS2 the corrosion reaction and HER occurred, respectively, at S and Fe sites are paralleled. Besides, density functional theory calculations also show that the Ni‐FeS2 exhibits the enhanced structural stability during the HER process after Ni2+ doping into FeS2.