Carrier effect in the synthesis of rattle-type Au@hollow silica nanospheres by impregnation and thermal decomposition method

It is very important and highly desired to improve the efficiency of noble metal nanoparticles (NPs) exclusively encapsulated into the cavities of hollow silica nanospheres (HSNs). In this article, four kinds of HSNs with varied pore structures and components were fabricated and used as catalyst carriers to investigate the encapsulation situation of Au NPs in the cavities of HSNs by impregnation and thermal decomposition method. HSNs with micropores in the shells and containing the residual ammonium polyacrylate (APA) in the cavities (as-HSNs-micropore) can successfully achieve the exclusive encapsulation of Au NPs into their cavities. It may be due to that the residual APA in the cavities plays an important dual role as captor of AuCl4- ions and as stabilizer of the formed Au clusters, thus finally leading to the formation of rattle-type NPs. And the rattle-type NPs show high catalytic activity and excellent stability in the catalytic reduction of 2-nitroaniline. (C) 2012 Elsevier Inc. All rights reserved.