Fe Atoms Accelerator Coupled With Oxygen Vacancies Channel Synergistically Boost OER Performance of Fe‐CoMoO ₄ ‐O _v Nanosheets

ABSTRACT CoMoO ₄ possesses a stable crystal structure, strong redox ability, and high terrestrial reserves, presenting broad application prospects in the field of electrocatalytic oxygen evolution reaction (OER). However, its poor electronic conductivity and weak catalytic activity necessitate appropriate surface modification before it can be used in the hydrogen production field. Therefore, we simultaneously introduced Fe atoms and oxygen vacancies to prepare Fe‐doped CoMoO ₄ nanosheets with abundant oxygen vacancies on the support of nickel foam (Fe‐CoMoO ₄ ‐O _v /NF). The doping of Fe atoms leads to the electronic structure modification of Co sites, thereby significantly reducing the energy required for surface transformation to form FeCoOOH. The positively charged oxygen vacancies can act as an “electronic channel” between Fe‐CoMoO ₄ ‐O _v and FeCoOOH, facilitating the seamless transfer of electrons between the two phases. Operando differential electrochemical mass spectrometry indicates that the OER process of Fe‐CoMoO ₄ ‐O _v /NF follows the typical adsorbate evolution mechanism, and density functional theory calculation results suggest that the introduction of Fe atoms and oxygen vacancies can not only reduce the band gap of Fe‐CoMoO ₄ ‐O _v to improve intrinsic electronic conductivity but also adjust the electronic structure of Co sites by shifting the d‐band center upward, thereby enhancing the adsorption energy of oxygen‐containing intermediates and significantly reducing the reaction energy barrier. Benefiting from this, the matched Fe‐CoMoO ₄ ‐O _v /NF||Pt/C/NF two‐electrode system and anion‐exchange membrane water electrolyzer (AEMWE) show considerable overall water splitting performance in alkaline water and even in alkaline natural seawater electrolytes. This research provides guiding significance for further promoting the performance of non‐noble metal‐based electrolytic water catalysts.