Akbari Nader, Shah Jafar Hussain, Hu Cejun, Nandy Subhajit, Aleshkevych Pavlo, Ge Rile, Farid Sumbal, Dong Changchang, Zhang Liang, Chae Keun Hwa, Xie Wei, Liu Taifeng, Wang Junhu, Najafpour Mohammad Mahdi
Department of Chemistry, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan, 45137-66731, Iran.
CAS Key Laboratory of Science and Technology on Applied Catalysis, Mössbauer Effect Data Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, China.
Angew Chem Int Ed Engl. 2025 Feb 3;64(6):e202418798. doi: 10.1002/anie.202418798. Epub 2024 Nov 19.
This study investigated the dynamic changes in NiFe (hydr)oxide and identified the role of high-valent Fe in the oxygen-evolution reaction (OER) within alkaline media via in situ techniques. Several high-valent Fe ions were found to remain considerably stable in the absence of potential in NiFe (hydr)oxide, even 96 hours after the OER. For Ni hydroxide treated with Fe ions, where Fe sites are introduced onto the surface of Ni hydroxide, no Fe species were detected at the rate-determining step (RDS). The findings of this study suggested that the oxidation of bulk Fe ions, similar to Ni ions, to high valent forms, is charge accumulation without a direct role in OER; these results offered a novel perspective on manipulating Fe states to optimize OER efficacy. The prevailing hypothesis suggested that trace amounts of high-valent Fe ions, notably those on the surface, directly participate in OER.
