Ultrasmall Mo₂C Nanoparticles Anchored on Porous Carbon as Electrocatalyst for the Hydrogen Evolution Reaction

Molybdenum carbide (Mo 2 C) has been considered as one of the most promising electrocatalysts toward hydrogen evolution reaction (HER) due to its platinum-like electronic configuration, low cost, and good corrosion resistance. However, there are still great challenges in real activity and durability for large-scale applications. Herein, we report the ultrasmall Mo 2 C nanoparticles with a particle size less than 2 nm anchored on porous carbon exhibits excellent HER performance with the overpotentials (η 10 ) of 156 mV and 130 mV in acidic and alkaline electrolytes, respectively. Furthermore, it also delivers a very stable life-span performance at a current density of around 20 mA cm –2 over 50 h with negligible decay. The nanopores in porous carbon are employed as nanoreactors to allow the reaction between its inside surface carbon atoms and Mo precursor to form the anchored Mo 2 C nanoparticles while avoiding the overgrowth of Mo 2 C particles at high temperatures in the annealing process. The high HER activity may be ascribed to the efficient exposure of active sites for ultrasmall particle size and the improved electron conductivity and ion transportation in the micro-3D configuration of the anchored structure in carbon pores.