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

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 (wa), 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.