Synergistic Tuning of the Electronic Structure of Mo₂C by P and Ni Codoping for Optimizing Electrocatalytic Hydrogen...

Developing earth-abundant and highly efficient nonprecious metal catalysts for hydrogen evolution reaction (HER) is critical for the storage and conversion of renewable energy sources. Molybdenum carbide (Mo₂C) has been extensively investigated as one of the most promising nonprecious electrocatalysts for boosting HER because of its low cost, high electrical conductivity, good chemical structure, and similar electronic structure to that of Pt. However, Mo₂C always exhibits the negative hydrogen-binding energy, which can largely prevent adsorbed H desorption during the HER process. Herein, we report P- and Ni-dual-doped Mo₂C in porous nitrogen-doped carbon (P/Ni-Mo₂C) as an electrocatalyst for the HER, exhibiting excellent activity and durability with a low overpotential of 165 mV at 10 mA cm^-2 in alkaline electrolyte. Density functional theory (DFT) calculations proved that P and Ni acted as the anion and cation, respectively, to synergistically tune the electronic properties of Mo₂C to decrease the negative hydrogen-binding energy, endowing the catalyst with excellent catalytic performance for the HER.