LAUSR

Molybdenum carbide materials are considered to be promising hydrogen evolution reaction (HER) electrocatalysts due to their similar electronic structures and catalytic activities to Pt-based catalysts. Here, we report a facile synthesis of β-Mo2C nanoparticles supported on nitrogen-doped carbon nanotubes (Mo2C/N–C) through a one-step carbonization of Mo-containing anion-doped polyaniline nanotubes. It has been revealed that the size of the obtained Mo2C nanoparticles can be effectively tuned by applying different Mo-containing anions. With MoO42– from Na2MoO4, the as-prepared Mo2C/N–C(S) with ultrasmall (2–3 nm) Mo2C nanoparticles shows excellent electrocatalytic HER activity in acidic media, with an overpotential of 189 mV vs reversible hydrogen electrode (RHE) at a geometric current density of −10 mA cm–2 and a Tafel slope of 58 mV dec–1. This study opens up a new avenue for the size-controllable synthesis of transition metal carbide nanoparticles loaded on carbon supports for energy conversion applicat...