Silicon and aluminum co-doping of titania nanoparticles: Effect on thermal stability, particle size and photocatalytic activity

Silicon and aluminum co-doped titania (TiO2) nanoparticles were fabricated by the sol–gel method. To investigate the effects of silicon and aluminum co-doping on thermal stability, microstructure and photocatalytic activity of TiO2 nanoparticles. Six batches of silicon-aluminum doped samples were characterized by X-ray diffraction (XRD), BET surface area measurement, scanning electron microscopy (SEM) and UV–vis absorption spectra. The photocatalytic activities were evaluated by the degradation of methylene blue (MB) under UV light irradiation. Experimental results revealed that silicon and aluminum co-doping helped to improve the crystal phase transition temperature of titania to 1200 °C and also decrease the particle size at high calcination temperature. A significant blue-shift was observed in the spectrum of UV–vis absorption. Additionally, it was found that silicon and aluminum co-doping exhibited better photocatalytic activity. The formation defects from solid solution reaction between Si4+, Al3+ and TiO2 effectively inhibits the crystal phase transition and grain growth of TiO2 nanoparticles.