Fe3+-Preactivated Ni/ Co-Based Antiperovskite Nitrides for Boosting Oxygen Evolution: Surface Tuning and Catalytic Mechanism

Ni/Co-based antiperovskite nitrides, featuring favorable electrical conductivity, have emerged as a class of alternatives to Ir/Ru-based catalysts and metal-oxide-based materials for the oxygen evolution reaction (OER). Nevertheless, OER intrinsic activities of these nitrides are insufficient. Herein, we demonstrate a general preactivation strategy of modifying antiperovskite nitrides with Fe3+ at the surface for facilitating OER. This preactivation on an antiperovskite ZnNNi3 array achieves 172 and 120 mV overpotential reductions at 100 mA cmgeo –2 and 0.1 mA cmcatalyst –2, respectively. This impressive enhancement is mainly attributed to an increase in the valence state of Ni species by the introduction of Fe cations in surface oxyhydroxides, which modifies the adsorption energy of intermediates and lowers the energy barrier of the rate-determining step. Such preactivation also works effectively on intrinsically improving the OER activity of other Ni- and Co-based antiperovskite nitrides. This work provides a general way to improve the OER activity of conductive nitride-based electrocatalysts.