CoIr Nanoalloy/N-Doped Ti₃C₂T_x MXene 0D/2D Heterojunction as a Catalyst for the Electrochemical Oxygen Evolution 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 Ti 3 C 2 T x MXenes for the alkaline OER. The resulting CoIr/N-Ti 3 C 2 T x 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-Ti 3 C 2 T x 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 IrO 2 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.