A unique adsorption-diffusion-decomposition mechanism for hydrogen evolution reaction towards high-efficiency Cr, Fe-modified CoP nanorod catalyst

The rational construction of high-efficiency transition metal phosphides catalysts for hydrogen evolution reaction (HER) is crucial since their sluggish kinetics of water dissociation remain severe barriers for HER performance. The theoretical calculations indicate a unique adsorption-diffusion-decomposition mechanism for H2O molecules on CoP (111) surface. Herein, Fe could decrease H2O decomposition barrier energies and increase the amount of active sites, along with Cr could accelerate H2O adsorption, diffusion and increase the conductivity of the reaction surface. Aided by this mechanism, a self-supported electrode of Cr and Fe dual-doped CoP nanorod arrays grown on nickel foam was prepared. The electrode only requires an overpotential of 27 mV at 10 mA cm-2 for alkaline HER with excellent durability for 400 h. Moreover, the catalyst presents only 1.505 V at 10 mA cm-2 for alkaline water electrolysis. This work provides an in-depth understanding on catalytic mechanism of CoP-based materials.