Optimized MoP with Pseudo-Single-Atom Tungsten for Efficient Hydrogen Electrocatalysis

The electrochemical hydrogen evolution reaction (HER) in alkaline medium is of great significance for the conversion of renewable energy into hydrogen fuel. Most catalysts exhibit limited HER performance in alkaline electrolytes due to the inefficient dissociation of water to initiate the Volmer reaction. Herein, we report the atomically dispersed tungsten (W)-optimized MoP nanoparticles on N,P-doped graphene oxide (W0.25Mo0.75P/PNC) that possesses high activity with impressively low overpotentials (η = 70 mV@10 mA cm-2, η = 49 mV@10 mA mgcat.-1) in alkaline medium. The catalyst features with the atomically isolated W atoms that can optimize the surface electronic structure by occupying the vacant Mo sites in the MoP lattice, corroborated by the X-ray absorption spectra, further leading to moderate hydrogen adsorption energy on the surface. The first-principles computation reveals that the atomically dispersed W atoms effectively reduce the water dissociation energy and facilitate the adsorption kinetics, leading to high activity. This work proposes an elegant design principle based on the pseudo-single-atom strategy to facilitate hydrogen electrocatalysis.