Asymmetric orbital hybridization in Zn-doped antiperovskite Cu1−xZnxNMn3 enables highly efficient electrocatalytic hydrogen production

Abstract

Rational design of efficient and robust earth-abundant alkaline hydrogen evolution reaction (HER) catalysts is a key factor for developing energy conversion technologies. Currently, antiperovskite nitride CuNMn₃ has garnered significant interest due to its remarkable properties such as negative/zero thermal expansion and magnetocaloric effects. However, when utilized as hydrogen evolution catalysts, it encounters large challenge resulting from excessively strong/weak interactions with adsorbed H on Mn/Cu active sites, which leads to low HER activity. In this study, we introduce an asymmetric orbital hybridization strategy in Zn-doped Cu_1−xZn_xNMn₃ by leveraging the localization of Zn electronic states to reconfigure the electronic structures of Cu and Mn, thereby reducing the energy barrier for water dissociation and optimizing Cu and Mn active sites for hydrogen adsorption and H₂ production. Electrochemical evaluations reveal that Cu_0.85Zn_0.15NMn₃ with x  = 0.15 demonstrates exceptional electrocatalytic activity in alkaline electrolytes. A low overpotential of 52 mV at 10 mA cm⁻² and outstanding stability over a 150-h test period are achieved, surpassing commercial Pt/C. This research offers a novel strategy for enhancing HER performance by modulating asymmetric hybridization of electron orbitals between multiple metal atoms within a material structure.