Graphite Carbon Nanosheet-Coated Cobalt-Doped Molybdenum Carbide Nanoparticles for Efficient Alkaline Hydrogen Evolution Reaction

Nanotransition-metal based carbide (TMC) electrocatalysts owing to the desirable metallic properties and platinum-like d-band electronic configuration have arisen as potential hydrogen evolution reaction (HER) electrocatalysts recently. Nevertheless, the correlation between cation incorporation and the intrinsic catalytic performance of bimetallic TMC-based electrocatalysts is still ambiguous. In addition, low-cost and simple preparation methods need to be further developed. Herein, a template-assisted method was developed to synthesize nanoscale metallic cobalt-doped β-Mo2C nanoparticles (Co-MC NPs), which were embedded in a two-dimensional graphite carbon nanosheet (2DGC) current collector. The obtained catalytic material has a rich pore structure and excellent electron transport properties due to the ingenious preparation method. Furthermore, it was revealed with electrochemical characterization and density functional theory (DFT) simulation that Co atom substitution could effectively weaken the strength of proton adsorption at the coordination of Mo and C atoms and synchronously facilitate the H2 desorption from the active sites of Co-MC/2DGC nanostructures. Therefore Co-MC/2DGC nanoparticles display a superior HER catalytic performance; that is, an overpotential of 103 mV is required to reach a current density of 10 mA cm–2 with a Tafel slope of 76.9 mV dec–1 along with an outstanding stability in alkaline.