Regulating reaction intermediate adsorption via electronic structural engineering of MoN/Co4N for efficient water splitting

Abstract

Integrating water electrolysis with green electricity presents a promising strategy for obtaining sustainable and clean energy. However, such a system requires electrodes capable of rapidly and stably adapting to fluctuating power supplies. Herein, a carbon layer embedded with MoN/Co₄N nanoparticles (MoN/Co₄N@NC) featuring abundant interfaces is successfully designed and fabricated. Benefiting from the favorable electron transfer behavior and optimized electronic structure, the MoN/Co₄N@NC electrocatalyst delivers superior hydrogen evolution reaction and oxygen evolution reaction performance, with small overpotentials of 29 mV and 146 mV at 10 mA cm⁻². Furthermore, when utilized as both the anode and cathode in anion exchange membrane water electrolysers, the MoN/Co₄N@NC catalyst exhibits enhanced catalytic activity and exceptional stability over 225 hours at a high current density of 600 mA cm⁻² for overall water splitting. Experimental characterization studies combined with density functional theory (DFT) calculations demonstrate that the modulation of the d-band center in MoN/Co₄N@NC is accomplished via charge redistribution at the heterointerface, leading to optimized adsorption strengths of reaction intermediates and consequently enhanced overall catalytic kinetics for water splitting. This work opens up a promising avenue for developing efficient bifunctional non-noble metal catalysts for industrial-scale water electrolysis through relay catalysis.