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.