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

ABSTRACT 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 Fe 2 O 3 ultrathin nanosheets (C‐Fe 2 O 3 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‐Fe 2 O 3 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 .