Strong electronic interaction in a P and Fe dual-doped Co3O4 nano-network structure supported on 3D Ni foam for highly efficient overall water splitting

Abstract

Developing highly efficient and durable bifunctional electrocatalysts to facilitate both the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) for water splitting is imminently needed. In this work, a cation and anion dual-doped P–Fe–Co₃O₄ nano-network structure on nickel foam (NF) was successfully fabricated. This novel catalyst exhibits overpotentials of merely 250 mV for the OER and 139.8 mV for the HER at current densities of 50 and 10 mA cm⁻², respectively, in 1 M KOH solution. Even at elevated current densities of 200 mA cm⁻² for the OER and 100 mA cm⁻² for the HER, the catalyst maintains its stability for over four days without significant loss in current density, indicating its promising potential for practical applications in environmental protection. More notably, the catalyst achieves overall water splitting at an extremely low voltage of 1.44 V at 10 mA cm⁻², demonstrating excellent stability for up to 100 h. The density functional theory (DFT) calculations indicate that the dual doping of Fe and P effectively modulates the electronic environment around the active site, optimizes the adsorption of reaction intermediates, and markedly improves the catalytic performance. All in all, this work provides a novel approach for commercial water electrolysis technology in renewable electrochemical energy conversion.