Synthesis of Porous Mo₂C/Nitrogen-Doped Carbon Nanocomposites for Efficient Hydrogen Evolution Reaction

Transition metal carbides are considered to be promising non-precious catalysts for electrochemical hydrogen evolution reaction (HER) because of their similar electronic structures to platinum-based materials. In this work, we report the synthesis of porous nanocomposites consisting of β-Mo₂C nanoparticles supported on nitrogen-doped carbon (NC) for efficient HER in both acidic and alkaline conditions. It is revealed that compared to the counterpart prepared through a one-step annealing, the two-step carbonization product (Mo₂C/NC-2) not only owns more catalytic active Mo₂C sites on the surface, but also has electron interaction between Mo₂C and NC. As a consequence, Mo₂C/NC-2 provides a geometric catalytic current density of −10 mA cm⁻² at overpotentials of 169 mV and 180 mV vs. reversible hydrogen electrode (RHE) and Tafel slopes of 55 and 60 mV dec⁻¹ in 0.5 M H₂SO₄ and 1 M KOH, respectively. This study provides valuable insights into the preparation of transition metal carbides with modulated surface structure and remarkable electrocatalytic activity for HER.