Fe-redox-oriented electrochemical activation strategy enabling enhancement for efficient oxygen evolution reaction

Creating highly effective electrocatalysts requires understanding how materials change under varied electrochemical conditions. While much effort has been devoted to investigating structural changes under operational conditions, deliberately exposing catalysts to non-operational potential regions to electrochemically activate the catalysts and improve the catalytic performance is an underexplored area. Enlightened by the fact that Fe species exhibit pronounced redox responses in alkaline solutions within a potential range that notably falls below the oxygen evolution reaction (OER) potential region, we propose an Fe-redox-oriented electrochemical activation approach to effectively alter the catalysts’ OER performance. This approach, involving pre-cycling catalysts within the Fe-redox-rich potential range, significantly enhances the OER performance of various Fe-containing materials. For the representative Fe₃O₄@NiO catalyst, this enhancement is primarily attributed to the formation of heterojunctions and a mixed Ni-Fe surface component, which results in a more favorable electronic structure for OER.