α-MoC1-x Quantum Dots Encapsulated in Nitrogen-Doped Carbon for Hydrogen Evolution Reaction at All pH Values

The development of highly effective, universal, and economical electrocatalysts for hydrogen evolution reaction (HER) via structure modulations remains a great challenge. Herein, we propose a novel solidoid nitridation reduction method to synthesize alpha-MoC1-x quantum dots encapsulated in nitrogen-doped carbon (alpha-MoC1-x/NC) with a shape like frog eggs. Carbon nitride was first prepared by pyrolysis of urea and then mixed with ammonium molybdate tetrahydrate under a temperature-programmed reduction. With the assistance of nitrogen release during thermal treatment, N doping and an ultrathin porous structure were obtained. Benefiting from the strong interaction of alpha-MoC(1-x )quantum dots and nitrogen-doped carbon, the alpha-MoC1-x/NC delivered an outstanding performance toward HER at all pH values. Here, 118 mV, a lower overpotential, is needed to reach 10 mA cm(-2) in alkaline solution, and the current density of alpha-MoC1-x grew much faster than the commercial Pt/C with increased potential. And, this can keep steadily electrolyzing over 60 h. Moreover, the alpha-MoC1-x/ NC electrode also has desirable performance in both neutral and acid solutions.