Sm/N-codoped TiO2 preparation, characterization, and photocatalytic decolourization of Acid Orange 7 and Basic Blue 41 in sunlight

A Sm/N-codoped TiO 2 photocatalyst was successfully prepared via a sol-gel method using ammonium hydroxide and samarium(III) acetylacetonate as nitrogen and samarium sources, respectively.The anatase phase of TiO 2 was mainly observed in a Sm/N-codoped product calcined at 500 °C as indicated by the X-ray diffraction pattern.The crystallite size of Sm/N-codoped TiO 2 ranged from 6-10 nm with a surface area (S BET ) of 109-155 m 2 /g.Photoelectron spectroscopic results confirmed the incorporation of both Sm and N species into the TiO 2 structure, which substantially lowered the band gap energy of TiO 2 .The photocatalyst activities were evaluated by the ability to decolourize solutions containing the organic azo dyes (i.e., AO7 and BB41) in sunlight.Sm/N-codoped TiO 2 calcined at 500 °C shows higher decolourization of AO7 than any other doped TiO 2 calcined at 500 °C, including undoped TiO 2 .Interestingly, Sm-doped TiO 2 calcined at 400 °C could most efficiently decolourize AO7.For the decolourization of BB41 dye, N-doped TiO 2 calcined at 500 °C showed the highest photocatalytic efficiency.