Mo-Based MXene-Supported Pt Nanoparticles for Highly Durable Oxygen Reduction in Acidic Electrolytes

Proton exchange membrane fuel cells suffer from performance degradation caused by the oxidation and corrosion of carbon supports. Metal–platinum interactions can enhance the catalytic activity and stability due to compositional and geometric effects. Two-dimensional MXenes have been intensively studied in recent years and are expanding rapidly in both types and applications. Recently, ORR performances of dual-transition metal MXenes with abundant surface Mo vacancy have been demonstrated as efficient electrocatalysts toward oxygen reduction reaction in an alkaline solution. In this study, the electrochemical performances of Mo-based MXenes-supported Pt electrocatalysts toward oxygen reduction reaction are investigated in an acidic solution. Compared with the Pt/C catalysts, Pt/Mo2TiC2Fx exhibits improved durability, with a 28.7 mV negative shift of the half-wave potential after continuous scanning of 5000 cycles, which is superior to Pt/C with an 84.3 mV negative shift. The proton-exchange membrane fuel cell with Pt/Mo2TiC2Fx as the cathode catalyst also shows excellent activity and stability with a 0.7% potential fade after 9 h. According to the morphology evolution during oxygen reduction, the excellence in electrochemistry is due to the coherent interface between Pt and MXene, which provides a high binding force between Pt nanoparticles and the supporting materials.