Ag decorated silica nanostructures for surface plasmon enhanced photocatalysis
In this article, we present a novel synthesis of mesoporous SiO2/Ag nanostructures for dye (methylene blue) adsorption and surface plasmon mediated photocatalysis. Mesoporous SiO2 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 SiO2 nanoparticles was compared with that of the mesoporous silica nanoparticles. The large surface area and higher porosity of mesoporous SiO2 facilitated better adsorption of the dye as compared to the non-porous silica. Ag decorated SiO2 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 SiO2/Ag was compared with that of non-porous SiO2/Ag nanoparticles and pristine Ag nanoparticles. Mesoporous SiO2 nanoparticles (kd = 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 SiO2 (kd = 25.1 × 10−3 g mg−1 min−1) and pristine Ag nanoparticles (kd = 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.