Inducing Intermolecular Oxygen Coupling by Introducing S and FeOOH on Co(OH)2 Nanoneedle Arrays for Industrial Water Oxidation

Abstract The design of electrocatalysts for oxygen evolution reaction (OER) remains a limitation of industrial hydrogen production by electrolysis of water. Excellent and stable OER catalysts can be developed by activating lattice oxygen and changing the reaction path. Herein, S and FeOOH on the Co(OH) 2 nanoneedle arrays are introduced to construct a heterostructure (S‐FeOOH/Co(OH) 2 /NF) as a proof of concept. Theoretical calculations and experimental suggest that the Co‐O‐Fe motif formed at the heterogeneous interface with the introduction of FeOOH, inducing electron transfer from Co to Fe, enhancing Co─O covalency and reducing intramolecular charge transfer energy, thereby stimulating direct intramolecular lattice oxygen coupling. Doping of S in FeOOH further accelerates electron transfer, improves lattice oxygen activity, and prevents dissolution of FeOOH. Consequently, the overpotential of S‐FeOOH/Co(OH) 2 /NF is only 199 mV at 10 mA cm −2 , and coupled with the Pt/C electrode can be up to 1 A cm −2 under 1.79 V and remain stable for over 120 h in an anion exchange membrane water electrolyzer (AEMWE). This work proposes a strategy for the design of efficient and stable electrocatalysts for industrial water electrolysis and promotes the commercialization of AEMWE.