Ir/Mn Co-Mixing and Oxide-Support Interaction Modulation Through Plasma Promoted Asymmetric Oxygen Coupling for Stable Acidic Oxygen Evolution

Developing efficient and stable catalysts that facilitate the oxygen-evolution reaction (OER) through an oxide-path mechanism (OPM) is of considerable interest. However, it remains a significant challenge due to the stringent structural requirements of these catalysts. This work reports that using a strategy that integrates the Ir/Mn co-mixing and the strong oxide-support interaction (SOSI) modulation, efficient and stable Ir-based catalysts that follow the OPM for the acidic OER can be developed. The strategy mainly relies on optimizing the distance of oxygeneous intermediate adsorption sites by the Ir/Mn co-mixing and modulating the SOSI of the catalysts through plasma defect engineering to trigger the OPM pathway with a lower energy barrier. The density-functional-theory (DFT) calculations reveal a strong electronic coupling between Ir and Mn via the Ir─O─Mn bond and a ready coupling of oxygeneous adsorbed on the Ir site with those on the Mn site, leading to an asymmetric oxygen coupling for the OER. The developed catalyst merely requires an overpotential of 240 mV to drive 10 mA cm⁻² with the Ir mass-activity > 75 times higher than that of the IrO₂. When used in the proton-exchange-membrane water-electrolyzers, it shows high performance and excellent stability at an industrial-level current density of 1.0 A cm⁻².