Synthesis of gold encapsulated in spherical carbon capsules with a mesoporous shell structure. A robust catalyst in a nanoreactor

Abstract

Core-shell templates containing an encapsulated Au nanoparticle in a mesoporous silica (Au@mSiO2) or nonporous silica (Au@SiO2) shell structure were made. The silicas were then covered with carbon by CVD using toluene and the silica was removed using HF. Au@mHCS and Au@HCS were both characterized by PXRD, HRTEM, TGA, BET and ICP-OES. The Au@mHCS yolk–shell composite exhibited excellent catalytic activity and reusability (10cycles) for the reduction of p-nitrophenol with conversion of up to 97% in 8min. Heat treatment of Au@mHCS at 800°C/4h/N2 did not alter the morphology or the catalytic activity significantly.