Locking the Lattice Oxygen in Commercial RuO ₂ for High Stable Proton Exchange Membrane Water Electrolysis

Abstract Efficient and sustainable hydrogen production via proton exchange membrane water electrolysis (PEMWE) requires the development of robust low‐cost oxygen evolution reaction catalysts. A robust acidic oxygen evolution reaction (OER) catalyst is fabricated, featuring single Co atoms incorporated into commercial RuO 2 (Co SA /RuO 2 ) and demonstrate that the Co sites suppress the mobility of lattice oxygen in commercial RuO 2 , thereby eliminating the stability‐limited lattice oxygen oxidation mechanism and improving the catalyst stability. The theoretical calculations reveal that the atomically dispersed Co sites shifts the εd‐dn of RuO 2 downward, optimizing the adsorption of O * and * OOH, thereby changing the rate‐determining step and improving the catalytic performance. In addition, atomically dispersed Co enhances the strength of the Ru–O lattice interaction, thereby alleviating the dissolution of Ru and effectively improving the stability of the catalyst under OER conditions. Specifically, the Co SA /RuO 2 ‐promoted PEMWE requires a voltage of 1.662 V to achieve a current density of 1 A cm −2 and can be stably performed for >550 h at 200 mA cm −2 with negligible performance decay. Thus, this work paves the way for the fabrication of highly active and stable ruthenium oxide–based OER catalysts and their use as alternatives to the costly Ir‐based counterparts.