Selective oxidation of cyclohexane over gold nanoparticles supported on mesoporous silica prepared in the presence of thioether functionality

Abstract

Gold (Au) nanoparticles (NPs) supported on mesoporous silica were prepared using a one-pot synthesis method in the presence of thioether functionality -(CH₂)₃-S-S-S-S-(CH₂)₃. Bis(triethoxysilyl) propane tetrasulfide was used as the source of thioether functionality. The complexation of thioether groups with tetrachloroauric anion (AuCl₄⁻) led to a good dispersion of Au NPs on mesoporous silica. Removal of the template and the thioether functional groups by calcination resulted in the reduction of the Au species, leaving behind Au NPs well dispersed on mesoporous silica. Selective oxidation of cyclohexane with molecular oxygen was used to evaluate the catalytic properties of the Au NP catalysts prepared using the present method and compared with that of a Au catalyst prepared using the hydrogen reduction method.