Characterization and photocatalytic activity of Sm3+-doped TiO2 nanocrystalline prepared by low temperature combustion method

Sm3+-doped TiO2 nanocrystalline has been successfully prepared by low temperature combustion synthesis (LCS). Results showed that the samarium doping was found to be able to significantly inhibit the anatase–rutile phase transformation. Photocatalytic degradation experiments indicated that doping samarium ions in TiO2 could enhance photocatalytic activity in photocatalytic degradation of methylene blue. The increase in photocatalytic activity is probably due to prevention of electron–hole recombination and the existence of a synergistic effect between anatase and rutile. The highest enhancement in photoreactivity was obtained at 0.5 mol% samarium ions doping, which may be in favor of the most efficient separation of the charge carriers. It has been found that the photocatalytic activity is drastically increased under the presence of a small amount of anatase phase (only 5.9% anatase) compared to pure rutile, and the sample calcined at 600 °C with 51.61% rutile shows the highest photocatalytic activity, which suggests the existence of a synergistic effect between anatase and rutile powders in the Sm3+-doped TiO2, which is similar to that of undoped TiO2.