SiO2 nanoparticles doped by 10 mol% Zr and 10 mol% Cu were prepared via sol-gel method under controled process. The effects of doping and calcination temperature on the structural and photo-catalytic properties of SiO2 nanopowders were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV-Vis absorption spectroscopy. The phases of cristobalite, quartz and tridymite were found at a calcinations temperature range of 800 to 1000 0C and only cristobalite phase was formed at a temperature of 1200 0C. The degradation of methyl orange was carried out for which results in under visible light radiation to indicate the effect of doped elements (Zr, Cu) on SiO2 which results in reducing the band gap effectively.
