Optimizing the electronic structure of Fe sites to enhance their redox performance by introducing Ce(Ⅳ)-O-Fe electron bridges in Ce-FeOOH for efficient oxygen evolution reaction

As an alternative to noble metal oxygen evolution reaction (OER) catalysts, iron-based materials face limitations in their practical applications due to their relatively low activity and conductivity, despite their cost-effectiveness. In this study, we developed a Ce-doped amorphous FeOOH catalyst (Ce-FeOOH) using an electron modulation strategy, leveraging the strong electron-absorbing capability of Ce 4+ ions to regulate the electronic structure of the FeOOH active site. Experimental results and characterizations demonstrated that Ce 4+ extract electrons from the iron sites via the Ce(IV)-O-Fe electronic bridges, generating highly active iron species with elevated oxidation states, thereby effectively enhancing the OER catalytic performance. The optimized Ce-FeOOH-3:2 exhibited outstanding OER performance in 1.0 M KOH, achieving a low overpotential of 248 mV at a current density of 10 mA cm −2 , a Tafel slope of 44 mV dec −1 . Moreover, the material exhibits stable continuous electrolysis performance for 100 h at overpotentials of 250 mV and 384 mV, respectively. This work provides a novel approach to synergistically modulating the electronic state of iron-based catalysts through high-valent metal doping and structural amorphization, offering valuable insights of the design and development of highly efficient and stable non-precious metal OER catalysts.