Engineering antiperovskite nitride for high-performing overall water splitting at ampere-level current densities

Owing to the structural and compositional flexibility feature, antiperovskites have garnered widespread attention, and been regarded as promising catalysts. However, their intrinsic sluggish kinetics impede their practical applications. Herein, a CoN 0.73 Co 3 @CoFeN(OH) x is constructed by a developed oxidation technology, endowing exceptional performance toward hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) at ampere-level current densities. The advanced nature of our as-prepared antiperovskite could be further evidenced by an assembled alkaline electrolyzer (CoN 0.73 Co 3 @CoFeN(OH) x ||CoN 0.73 Co 3 @CoFeN(OH) x ), yielding a current density of 1000 mA/cm 2 with 1.89 V, and stable working for over 100 h. Operando characterizations clarify that iron atoms in the antiperovskite skin promote the generation of CoOOH active species. Theoretical calculations are referred to understand the decent catalytic activity, which reveals that Fe atoms are responsible for the favorable adsorption of the OOH oxygen intermediate and modulate the hydrogen adsorption strength. This work paves a solid way for engineering the antiperovskites for green hydrogen generation applications.