Photocatalytic degradation of methyl red dye by silica nanoparticles

Silica nanoparticles (SiO(2) NPs) were found to be photocatalytically active for degradation of methyl red dye (MR). The SiO(2) NPs and SiO(2) NPs doped with silver (and or) gold nanoparticles were prepared. From the transmission electron microscopy (TEM) images the particle size and particle morphology of catalysts were monitored. Moreover, SiO(2) NPs doped with silver and gold ions were used as a photocatalyst for degradation of MR. The rate of photocatalytic degradation of MR was found to be increased in the order of SiO(2) NPs, SiO(2) NPs coated with gold nanoparticles (Au NPs) and silver nanoparticles (Ag NPs), SiO(2) NPs coated with Ag NPs, SiO(2) NPs coated with Au NPs, Ag(+)-doped SiO(2) NPs, and Au(3+)-doped SiO(2) NPs. The kinetic and mechanism of photocatalytic reaction were studied and accorded well with experimental results. (C) 2007 Elsevier B.V. All rights reserved.