Extension of optical properties of ZnO/SiO2 materials induced by incorporation of Au or NiO nanoparticles

Incorporating noble metal nanoparticles (NPs) and oxides has been proved to be an effective method to tune the optical properties of silica based materials. In this paper the optical and photocatalytic properties have been studied for ZnO/SiO 2 modified with Au or NiO nanoparticles. Changes in the optical properties of semiconductor ZnO particles have been observed due to the deposition of coloured Au and NiO nanoparticles by reducing the band gap energy and thus extending light absorption to visible domain. The excellent surface characteristics of NiO/ZnO/SiO 2 and Au/ZnO/SiO 2 favour the adsorption behaviour of these materials and limit the recombination of electron–holes pairs. Crystal Violet degradation under VIS light proved to have higher efficiency in the presence of Au/ZnO/SiO 2 (97%) than for NiO/ZnO/SiO 2 (60%).