Visible-Light-Induced Photocatalysis of 2D-Hexagonal Mesoporous SiO₂–TiO₂ Deposited with Au Nanoparticles

Au nanoparticles (NPs) are deposited using a couple of methods onto a sol–gel-derived mesoporous SiO₂–TiO₂ template. A modification of the template with 3-aminopropyltriethoxysilane (APTES) before the deposition of Au leads to the formation of Au nanorods instead of Au nanospheres in the tubular mesopores. The modification also causes a deterioration of visible-light-induced photocatalytic activity. Heat treatment of this sample to remove APTES results in an amelioration of the photocatalytic activity. The detailed mechanism of the deterioration and amelioration of the activity is discussed on the accessibility of the reactant to the sample and the easiness of the charge carrier transfer between TiO₂ and Au NPs.