Co/MoN Hetero-Interface Nanoflake Array with Enhanced Water Dissociation Capability Achieves the Pt-like Hydrogen Evolution Catalytic Performance

Abstract Developing high-performance electrocatalyst for hydrogen evolution reaction (HER) is paramount for hydrogen economy. Molybdenum-based nitrides (MoNx) are promising HER catalysts in alkaline condition; however, the performance is greatly limited by the weak water dissociation capacity to form adsorbed H* from H2O, which is crucial but long ignored. Herein, we develop a new strategy to enhance the water dissociation capacity of MoN by forming Co/MoN hetero-interface nanoflake array. The electronic structure of MoN can be effectively modulated by the electron transfer occurred at the Co/MoN hetero-interface. Co/MoN nanoarray also possesses a significantly increased electrochemically active surface area. Co/MoN nanoarray thus exhibits remarkable HER activity with an overpotential of 132 mV to reach 100 mA/cm2, which is among the best non-noble metal HER electrocatalysts in alkaline solution. The very low energy barrier of -0.04 eV for water dissociation on Co/MoN calculated by density functional theory confirms the strong water dissociation capability.