Dual-phase engineering of MoN/Co4N with tailored electronic structure for enhanced hydrogen evolution

Abstract Searching for cost-effective electrocatalysts with remarkable catalytic activity and stability toward hydrogen evolution reaction (HER) under a wide range of pH values is highly desirable for the commercialization of water electrolysis. Herein, a facile strategy is reported to introduce MoN/Co4N heterostructures on Co4N nanosheets. Benefitting from the synergistic effect between the integrated heterostructure with tailored electronic structure and abundant active sites, the resultant MoN/Co4N exhibits superior catalytic performance and stability toward HER, with the overpotentials of 34, 44, and 72 mV to obtain the current density of 10 mA cm-2 in alkaline, acidic, and neutral electrolytes, respectively. Combined with Density functional theory (DFT) calculations and experimental results, we find that the enhanced HER performance of MoN/Co4N is derived from the appropriately increased adsorption free energy of H2O, optimized adsorption free energy of hydrogen, as well as facilitated diffusion of Had and desorption of H2.