LAUSR

Abstract Herein, based on our DFT-calculation, it is the first time to uncover the fact that the catalytic property of Mo2C is related to the concentration of doped-N atoms which plays a critical role in weakening the hydrogen absorption ability of Mo2C electrocatalysts and enhancing their catalytic property. When its surface is saturated with N atoms, Mo2C exhibits the best catalytic performance. Guided by this calculation result we highlight a strategy to synthesize Mo2C electrocatalysts whose surface is fully occupied by N atoms. Our electrocatalysts exhibit a low overpotential of 57 mV vs. RHE at the current density of 10 mA cm−2 and a small Tafel slope of 80 mV dec−1 in 1.0 M KOH for HER which is comparable with the commercial Pt-based electrocatalyst (overpotential of 39 mV at 10 mA cm−2, Tafel slope of 69 mV dec−1). Moreover, our strategy is regarded as a general method which is successfully extended and applied to improve other metal carbide electrocatalysts such as nickel carbide. This work will pave a way for the understanding and optimization of metal carbide electrocatalysts in HER.