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/Mo2TiC2F x 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/Mo2TiC2F (x) 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.