Confined growth of pyridinic N Mo2C sites on MXenes for hydrogen evolution
Developing low cost and high performance hydrogen evolution reaction (HER) electrocatalysts is a key research area for scalable hydrogen production from water electrolysis. Here, a hybrid of nitrogen doped carbon encapsulated Mo2C nanodots on Ti3C2Tx MXene (Mo2C/Ti3C2Tx@NC) is developed through in situ polymerization of dopamine and a Mo precursor on the Ti3C2Tx MXene surface. During the annealing treatment, the polydopamine plays multiple roles in forming N doped carbon, confining MoO42 ions into ultrasmall Mo2C nanodots, and stabilizing the MXene flakes against spontaneous oxidation. The as synthesized hybrid exhibits excellent HER activity in acidic electrolyte with an overpotential of 53 mV at 10 mA cm 2 and excellent stability over 30 hours. The combination of experiments and simulations demonstrates that pyridinic N doped carbon coated Mo2C nanodots serve as the active sites and Ti3C2Tx MXene facilitates the charge transfer, synergistically contributing to the superior HER performance.