Mechanochemical Synthesis of Pt/Nb₂CT_x MXene Composites for Enhanced Electrocatalytic Hydrogen Evolution

Production of hydrogen from water splitting has been considered as a promising solution for energy conversion and storage. Since a noble metal-based structure is still the most satisfactory but scarce kind of catalyst, it is significant to allow for practical application of such catalysts by engineering the heterogeneous structure and developing green and facile synthetic strategies. Herein, we report a mechanochemical ball milling synthesis of platinum nanoclusters immobilized on a 2D transition metal carbide MXene (Nb₂CT_x) as an enhanced catalyst for hydrogen evolution. After annealing at 600 °C, ultrafine Pt₃Nb nanoclusters are formed on the Pt/Nb₂CT_x catalyst. As prepared, the Pt/Nb₂CT_x-600 catalyst demonstrates superior electrochemical HER activity and stability with an ultralow overpotential of 5 mV and 46 mV to achieve 10 mA cm^-2 and 100 mA cm^-2, respectively, in comparison with other Nb₂CT_x-based catalysts and commercial Pt/C catalysts. Moreover, the remarkable durability is also confirmed by accelerated durability tests (ADTs) and long-term chronoamperometry (CA) tests. The excellent HER performance was attributed to high Pt dispersion and more active site exposure by the mechanochemical process and thermal treatment. Such results suggest that the mechanochemical strategy provides a novel approach for rational design and cost-effective production of electrocatalysts, also providing other potential applications in a wide range of areas.