Immobilization of Pt nanoparticles in hollow mesoporous silica nanocapsules: An aggregation- and leaching-resistant catalyst

Abstract

In this study, hollow mesoporous silica nanocapsules (h-mNSiO2) with uniformly dispersed Pt nanoparticles (Pt NPs) in their hollow core (Pt@h-mNSiO2) were successfully fabricated. The as-synthesized Pt@h-mNSiO2 was core@shell like structure with silica shells and Pt-rich cores. The catalyst was synthesised in an oil-water biphasic stratification system, then the self-assembly of reactants occurred in the oil-water interface for one-pot sustaining interfacial growth. The as-prepared Pt@h-mNSiO2 catalyst exhibited superior activity for hydrogen generation from the hydrolysis of ammonia borane, with a turnover frequency of 371.7 molH2 mol−1Pt min−1 at ambient temperature, probably owing to the abundant mesopores and high surface area, leading to a considerable increase in the accessible active sites. Besides, almost no Pt NP aggregation was observed during reusability tests. Notably, Pt leaching was not observed during the reaction, possibly related to the protective effect of the mesoporous silica shell. Thus, this study provides a facile route to synthesise aggregation- and leaching-resistant catalysts with superior activity, accessibility, and recyclability for the environment and energy chemistry.