Facile and controllable fabrication of gold nanoparticles-immobilized hollow silica particles and their high catalytic activity

Abstract

A facile and controllable method of immobilizing gold nanoparticles (AuNPs) on hollow silica particles (SiO₂HPs) is proposed and the resultant SiO₂HP/AuNP composite particles exhibit high catalytic activity. The carrier SiO₂HPs decorated with amino groups are prepared in a W/O inverse emulsion, having a well-defined hollow structure, mesoporous wall and dense bush-like surface morphology. A large number of ultrafine AuNPs are generated via in situ reduction of chloroauric acid by the amino groups and firmly anchored on the bush-like silica shell. The structure and morphology of the composites are governed by changing the weight percentage of 3-aminopropyltriethoxysilane in the total amount of monomers (w_a), which have been extensively characterized. Benefiting from the unique multiple structures, the composite particles exhibited outstanding catalytic efficiency and repeatability, which are confirmed by two oxidation–reduction reactions of 2-nitroaniline/NaBH₄ and 4-nitrophenol/NaBH₄.