Electrocatalytic selective oxygen evolution of FeOOH-modified perovskite for alkaline seawater electrolysis

Seawater electrolysis is fundamental for the large-scale production of green hydrogen. The development of durable, highly active oxygen evolution reaction (OER) catalysts represents a key challenge in advancing this technology given the competitive adsorption and corrosion effect of chloride (Cl⁻) ions to the catalysts in seawater. Herein, a novel surface modification strategy, depositing FeOOH onto the CaSrCo₂O₅ (CSC) surface, is reported to promote OH⁻ adsorption and induce the lattice oxygen-participated OER. The combined ex situ and in situ tests reveal that FeOOH modification can improve the electronic structure, enhance the OH⁻ adsorption, and suppress Cl⁻ adsorption of CSC in alkaline seawater. Notably, the superior OH⁻ adsorption capacity of composite CSC-Fe can activate the lattice oxygen participation mechanism (LOM) and improve the structural stability during OER. Contributed to such synergetic catalysis mechanism, CSC-Fe exhibits a low OER overpotential of 359 mV in alkaline simulated seawater. More importantly, the CSC-Fe (+) || Pt/C (−) electrolyzer cell displays a small potential of 1.60 V at 10 mA cm⁻², which can be maintained throughout 150-h continuous operation. The findings shown in this work can potentially be applied to the other family of oxides and pave a way toward realizing hydrogen energy economy.