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.