2D Co₆Mo₆C Nanosheets as Robust Hydrogen Evolution Reaction Electrocatalyst

Abstract Hydrogen production by electrochemical water splitting via nonprecious metal catalysts is still a great challenge due to sluggish kinetics and poor electrochemical durability toward hydrogen evolution reaction (HER). In this work, the fabrication of two dimensional (2D) bimetallic carbide nanosheets on graphene hybrid (Co₆Mo₆C NSs/G) is first reported, which exhibits excellent HER performance with a nearly zero onset overpotential, a small overpotential of 73 mV at current densities of 10 mA cm⁻², a small Tafel slope of 43 mV dec⁻¹, and an outstanding electrochemical durability. The density functional theoretical calculations suggest that the Gibbs free energy of hydrogen bonding of Co₆Mo₆C is −0.12 eV, which is very close to Pt (−0.09 eV).