Oxygen-bridged electronic coupling of Ir single-atom sites for durable acidic oxygen evolution reaction

Abstract

Developing stable and efficient single-atom electrocatalysts for the acidic oxygen evolution reaction (OER) is crucial for advancing proton exchange membrane water electrolysis (PEMWE). However, the lack of precisely tailored coordination environments capable of preventing noble metal single-atom dissolution remains a critical barrier. Herein, we construct Ir single-atom catalysts supported on Co3O4 (IrSA-Co3O4) via the synchronized formation of cobalt defects and the immobilization of Ir single atoms during precursor pyrolysis. Atomically dispersed Ir atoms are anchored at octahedral cobalt defect sites, forming a configuration of single atoms confined within the spinel lattice. Benefiting from the oxygen-bridged electronic coupling within the Ir-O-Co configuration, the electronic structure of Ir sites is optimized to enable moderate intermediate adsorption while mitigating dissolution during acidic OER. As a result, IrSA-Co3O4 achieves a low overpotential of 199 mV at 10 mA cm -2 in 0.5 M H2SO4 and operates stably for 150 h at 200 mA cm -2 in PEMWE. This work provides new insights into the rational design of stable single-atom catalysts for acidic OER by effectively suppressing active-site dissolution.