Optimizing nickel and cobalt-based water oxidation electrocatalysts via iron post-modification

Nickel (Ni) and cobalt (Co)-based oxides are promising candidates for the oxygen evolution reaction (OER). Many experimental studies have shown that incorporating iron (Fe) into Ni/Co-based materials can markedly enhance OER activity, while the degree of activity improvement strongly depends on how Fe is introduced. Compared to traditional bulk doping and electrochemical deposition strategies, Fe post-treatment has become a more effective approach to unlocking the OER potential of Ni/Co-based materials, bringing activity improvements beyond the limits of conventional modifications. This review focuses on the specific approaches and underlying mechanisms of Fe post-treatment for Ni/Co electrocatalysts. A key emphasis is placed on the unique advantages of Fe post-treatment over traditional bulk doping and electrochemical deposition strategies. Representative studies are then categorized according to the structure of precursor materials to illustrate the multifunctional roles of Fe post-treatment in promoting the OER performance. Finally, the review outlines current challenges and future opportunities for the precise design of Fe-modulated water oxidation catalysts.