Solvothermal synthesis of SrTiO₃-LnTiO₂N solid solution and their visible light responsive photocatalytic properties

SrTiO₃-LnTiO₂N solid solution, Sr_1−xLa_xTiO_3-yN_y, was synthesized by the solvothermal reactions in KOH aqueous solution using [(CH₃)₂CHO]₄Ti, SrCl₂.6H₂O, La(NO₃)₃.6H₂O and HMT (hexamethylenetetramine) as raw materials. The samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), thermogravimetric and differential thermal analysis (TG-DTA) and diffuse reflectance spectra. The nano particles of perovskite type Sr_1−xLa_xTiO_3-yN_y (x = 0, 0.025, 0.05 and 0.1 named as ST, STN-0.025, STN-0.05 and STN-0.1) were successfully synthesized by solvothermal method. The photocatalytic activity of SrTiO₃ for DeNO_x ability in visible light region (>510nm) could be improved by co-doping of La³⁺ and N³⁻. The high visible light photocatalytic activity of this substance may be due to generating of a new band gap that enables to absorb visible light. The photocatalytic activity of Sr_1−xLa_xTiO_3-yN_y changed with variation of La content. The powder with smaller ratio of La content possessed excellent photocatalytic activity under visible light irradiation.