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

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.

Automated summary

Ni-doped FeS2 nanowire arrays (Ni-FeS2 NWs), fabricated through a simple doping strategy, exhibit enhanced antiacid stability and catalytic activity for the hydrogen evolution reaction (HER) compared to FeS2. This is attributed to the different HER active centers at S and Fe sites in Ni-FeS2 and FeS2, respectively.