Rapid template-guided ligand-free synthesis of ultrasmall Pt nanoclusters with efficient hydrogen evolution reaction activity and their versatile release

The design of ligand-free platinum nanoclusters (PtNCs) for the field of renewable energy is still challenging. Herein, we reported a fast synthesis of ligand-free Pt nanoclusters (NCs) by utilizing the outer defect of a representative type of zeolitic imidazolate framework (ZIF). Structural investigation suggests a homogenous distribution of the PtNCs on the outer layer of the ZIF-8 structure. The as-prepared PtNCs@ZIF-8 exhibits high catalytic activity for the hydrogen evolution reaction (HER). The extremely low overpotential with 1.4 mV, high kinetic current (specific and mass activity at 50 mV), and larger exchange current density were achieved in acidic solution, better than those of the commercial 20% Pt/C catalysts under the same condition. Furthermore, the PtNCs can be extracted from the ZIF-8 structure to both aqueous and non-aqueous solvent, which could be further used for other systems. These findings allow for a simple route of template-guided NC synthesis and their release.