CoIr Nanoalloy/N-DopedTi₃C₂T_<i>x</i> MXene 0D/2DHeterojunction as a Catalystfor the Electrochemical OxygenEvolution Reaction

Developing high-efficiency oxygen evolution reaction (OER) electrocatalysts is essential for industrial application of sustainable energy conversion and storage systems, which can address energy and environmental challenges. We herein use an ultrasonic-assisted reduction strategy to design an efficient 0D/2D heterojunction by strongly coupling CoIr nanoalloys and N-doped Ti₃C₂T_<i>x</i> MXenes for the alkaline OER. The resulting CoIr/N-Ti₃C₂T_<i>x</i> heterojunction not only modifies the electronic structure of Ir sites but also enhances the exposure of active sites, thereby optimizing the adsorption strength of oxygen-related intermediates and significantly lowering the reaction energy barrier for the OER. The CoIr/N-Ti₃C₂T_<i>x</i> catalyst with a low Ir content (5.12 wt %) only requires a low activation energy of 30.66 kJ mol^–1 and a small OER overpotential of 260 mV_RHE at 10 mA cm^–2, outperforming the commercial IrO₂ catalyst. The as-made OER electrocatalyst also shows high catalytic stability for at least 30 h of testing, highlighting that constructing MXene-based heterojunctions is a promising route to achieve high-performance OER electrocatalysts.