Low-Level Fe Doping in CoMoO4 Enhances Surface Reconstruction and Electronic Modulation Creating an Outstanding OER Electrocatalyst for Water Splitting

Abstract

Efficient and stable nonprecious metal-based oxygen evolution reaction (OER) electrocatalysts are pivotal for water electrolysis technology. Herein, we are reporting an effective strategy for fabricating efficient Co-based OER electrocatalysts by low-level Fe doping in CoMoO₄ to boost surface reconstruction and electronic modulation, which resulted in excellent OER electroactivity consequently. Our findings reveal that a mere 5.30% (wt %) of Fe doping can raise the O 2p band center energy nearer to the Fermi level, reduce the energy barrier for oxygen vacancy (V_O) formation, and significantly enhance OER electrocatalytic activity. Additionally, the fast dissolution of Mo in the initial reaction facilitated surface reconstruction to form active oxyhydroxide species and stabilized Fe and Co from leaching. As a result, the optimized catalyst Fe-CoMoO₄-0.2 exhibited a low overpotential of 276 mV at 10 mA cm^–2 in 1 M KOH and can operate stably at a current density of 20 mA cm^–2 for at least 24 h under water splitting conditions. This work provides an excellent example of regulating the surface structure and electronic properties of the OER catalysts.