Molten-Salt Motivated MXene-Based Heterostructure Activate Pt Clusters for Hydrogen Evolution Reaction

Atomic clusters exhibit superior performance in heterogeneous catalysis due to their unique electronic states and highly exposed active surfaces. Nevertheless, significant challenges persist in achieving the precise and efficient synthesis of atomic clusters while preventing undesirable formation of coexisting species, particularly nanoparticles. Herein, a one-step in situ phase transition engineering strategy is reported for the synthesis of atomic platinum clusters by vapor deposition on Ti₃C₂Cl₂ MXene and TiC heterogeneous interface (Pt-MXene/TiC) in molten salt, where Pt clusters can be acquired over a slight amount of Pt contents (0.298 wt.%). The strongly polarized molten salt induces the desired confinement of atomic-scale Pt clusters. The construction of heterogeneous interfaces enhances the local electric field and accelerates the electron transfer between Pt and the substrate. As a result, Pt-MXene/TiC-950 exhibits an exceptional increase in mass activity and turnover frequency (TOF) for hydrogen evolution reaction (HER) at 49.4 and 46.7 folds of 10% commercial Pt/C. Further theoretical calculations elucidate that the Pt species in Pt-MXene/TiC-950 possess moderate d-band center, which enables optimized selectivity and activity for intermediates adsorption in HER process. This work provides some guidelines for leveraging molten salt and heterostructure to enhance the precision and synthesis efficiency of atomic clusters.