The Fe Site in Non-Precious Metal Nanocatalysts toward Efficient Water Oxidation

Abstract

Water electrolysis is a pivotal technology for renewable hydrogen production. Iron (Fe), due to its abundant reserves, low cost, versatile valence states, tunable coordination structures, and co-friendliness under alkaline conditions, makes it a key alternative to precious metals as a catalytic center. Although extensive studies have demonstrated that Fe sites can significantly boost the oxygen evolution reaction (OER) performance of non-precious metal catalysts, there is still no profoundly understanding on the intrinsic role for Fe sites in the OER process. This paper systematically reviews the core function of Fe sites in nanocatalysts during water electrolysis, including their electronic and spin structures, catalytic behaviors and fundamental reaction mechanisms. It addresses how electronic structure, valence evolution and coordination environment regulate intermediate adsorption, desorption barriers and reaction pathways, and summarizes typical strategies for introducing Fe sites and optimizing catalytic activity and stability. Moreover, the advanced characterization for identifying active-site evolution is also highlighted. Finally, the challenges facing Fe sites in catalysts and corresponding solutions are analyzed and offers an outlook for the rational design and large-scale application of non-precious metal catalysts by Fe-introduction.