Ultrastable Non-Noble-Metal Oxygen Evolution Electrocatalyst for Industrial-Level Water Electrolysis

The sluggish kinetics of alkaline oxygen evolution reaction (OER), together with the highly polarizing conditions at industrial-level ampere-scale current densities, which cause catalyst instability, motivate the search for new approaches to break the challenging activity-stability trade-off. Herein, we demonstrate that atomic carbon doping into the octahedral voids of Fe₂O₃ ultrathin nanosheets (C-Fe₂O₃ UNSs) with constructed Fe_oh ^III-O-Fe_oh ^III synergistic centers can modify the coverage of ^*OH intermediates and allow direct ^*O-^*O radical coupling. This enables both structural and catalytic stabilization, as confirmed by operando spectroscopic measurements and density-functional theory calculations, with an overpotential of 227 mV to achieve 500 mA cm^-2 along with 4500-h durability. When applying C-Fe₂O₃ UNSs in an anion exchange membrane water electrolyzer, it delivers a cell voltage of 1.72 V at 1.5 A cm^-2 while operating for 2800 h from 1 to 5 A cm^-2, with a degradation rate of 3.05 mV kh^-1 at 3 A cm^-2.