Enhancing Oxygen Evolution Reaction Performance via Zn/Fe Co-Doping in Co3O4 Nanostructure: Mechanistic Insights and Surface Reconstruction Dynamics

The kinetics of the oxygen evolution reaction (OER) of Co3O4 in alkaline media can be promoted by a bimetallic co-doping strategy. Herein, we synthesize a Zn/Fe co-doped Co3O4 nanostructure (ZnFe-Co3O4) to enhance the oxygen evolution reaction performance in the alkaline media. The ZnFe-Co3O4 electrocatalyst exhibits a low overpotentials of 255 mV at 10 mA cm-2, a Tafel slope of 54 mV dec-1 in 1.0 M KOH and excellent long-term durability up to 120 hours at 100 mA cm−2. The X-ray photoelectron spectroscopy (XPS) reveals that Zn occupies octahedral Co3+ sites and Fe occupies tetrahedral Co2+ sites in the Co3O4 lattice. The experimental results together with theory calculations collectively demonstrate that ZnFe-Co3O4 follows the lattice oxygen mechanism (LOM) during OER process. In situ Raman spectroscopy shows that the truly reactive FeOOH/CoOOH species are formed through surface reconstruction during OER. Furthermore, it is found that the synergistic effects of Zn and Fe doping, which stabilize the Co3O4 structure and promote the generation of active (oxy)hydroxide species, are identified as key factors in the enhanced electrocatalytic performance. This work offers a novel concept for enhancing the electrocatalytic activity of electrocatalysts through doping strategies and provides guidance for the rational design of ideal electrocatalyst.