Enhanced oxygen evolution catalytic activity of NiS2 by coupling with ferrous phosphite and phosphide

Abstract

We develop a facile method to improve the OER performance of NiS₂ nanospheres by coupling ferrous phosphite and phosphide (simply abbreviated as Fe-P) with NiS₂. The as prepared NiS₂/Fe-P nanospheres possess abundant interfaces which can not only enrich the electroactive sites but also promote electronic transfer, thus further facilitating intrinsic activity for the OER. Consequently, optimal NiS₂/Fe-P exhibits outstanding OER activity with an ultralow overpotential of only 218 mV at a current density of 10 mA cm⁻² and a Tafel slope of 47.5 mV dec⁻¹. More importantly, it can achieve a relatively high current density of 800 mA cm⁻² with an overpotential of only 306 mV, as well as pretty good stability after 160 h testing, which is beneficial for practical applications.