Synthesis and photocatalytic activity of nanocrystalline TiO2–SrO composite powders under visible light irradiation

Nano-sized homogeneously distributed TiO2–20, –40, –60 wt.% SrO composite powders were successfully synthesized by a sol–gel method. The as-received amorphous TiO2—20 wt.% SrO composite powders were crystallized with anatase TiO2 at around 750 °C. As calcination temperatures increased, the anatase TiO2 crystalline phase was transformed to rutile TiO2 at about 900 °C, whereas nano-sized, squarish SrTiO3 phase was detected. The peaks obtained after calcining at 1050 °C mainly exhibited the rutile TiO2 and SrTiO3 phases. However, a small number of SrO2 peaks were also detected. For the comparison of photocatalytic activity depending on light sources, TiO2–SrO composite powders were tested in phenol degradation. TiO2–60 wt.% SrO composite powder showed good visible light photoactivity for the photo-oxidation of phenol.