Ag decorated silica nanostructures for surface plasmon enhanced photocatalysis.

In this article, we present a novel synthesis of mesoporous SiO 2 /Ag nanostructures for dye (methylene blue) adsorption and surface plasmon mediated photocatalysis. Mesoporous SiO 2 nanoparticles with a pore size of 3.2 nm were synthesized using cetyltrimethylammonium bromide as a structure directing agent and functionalized with (3-aminopropyl)trimethoxysilane to introduce amine groups. The adsorption behavior of non-porous SiO 2 nanoparticles was compared with that of the mesoporous silica nanoparticles. The large surface area and higher porosity of mesoporous SiO 2 facilitated better adsorption of the dye as compared to the non-porous silica. Ag decorated SiO 2 nanoparticles were synthesized by attaching silver (Ag) nanoparticles of different morphologies, i.e. spherical and triangular, on amine functionalized silica. The photocatalytic activity of the mesoporous SiO 2 /Ag was compared with that of non-porous SiO 2 /Ag nanoparticles and pristine Ag nanoparticles. Mesoporous SiO 2 nanoparticles ( k d = 31.3 × 10 -3 g mg -1 min -1 ) showed remarkable improvement in the rate of degradation of methylene blue as compared to non-porous SiO 2 ( k d = 25.1 × 10 -3 g mg -1 min -1 ) and pristine Ag nanoparticles ( k d = 19.3 × 10 -3 g mg -1 min -1 ). Blue Ag nanoparticles, owing to their better charge carrier generation and enhanced surface plasmon resonance, exhibited superior photocatalysis performance as compared to yellow Ag nanoparticles in all nanostructures.