Doping β-CoMoO4 Nanoplates with Phosphorus for Efficient Hydrogen Evolution Reaction in Alkaline Media

Mass production of hydrogen by electrolysis of water largely hinges on the development of highly efficient and economical electrocatalysts for hydrogen evolution reaction (HER). Though having the merits of high earth abundance, easy availability, and tunable composition, transition-metal oxides are usually deemed as poor electrocatalysts for HER. Herein, we demonstrate that doping β-CoMoO4 nanoplates with phosphorus can turn them into active electrocatalysts for HER. Theoretical calculation and experimental studies unravel that enhanced electrical conductivity and optimized hydrogen adsorption free energy are major causes for the improvement of intrinsic activity. As a result, only an overpotential of 138 mV is required to drive hydrogen evolving at a current density of 10 mA cm-2 in 1 M KOH for P-doped β-CoMoO4, which outstrips many recently reported transition-metal oxides and is just slightly inferior to commercial Pt/C. This work opens a new route to tune the HER performance of transition-metal oxides.