Constructing heterogeneous interface between CoO and RuO with enhanced electronic regulation for efficient oxygen evolution reaction at large current density.

Exploring effective strategies for developing new high-efficiency catalysts for water splitting is essential for advancing hydrogen energy technology. Herein, CoO/RuO heterojunction interface is construct through ion exchange reaction and pyrolysis. The as-synthesized CoO/RuO-4 exhibits outstanding oxygen evolution reaction (OER) activity at the current density of 100 mA cm with a low overpotential of 276 mV, and remarkable stability (maintaining activity for 60 h at 100 mA cm). Experimental results and theoretical calculations reveal that the electrons around the heterogeneous interface transferred from RuO to CoO, resulting in electron redistribution and optimization of energy barriers for OER intermediates. This unique composite catalyst structure offers a new potential for designing efficient oxygen electrocatalysts at large current density.