Synthesis and photocatalytic properties of Cr-doped SrTiO3 with Ti deficiency for enhanced photocatalytic activity

The new design of SrTiO3 based photocatalyst is very challenging due to its stability and high activity in visible light irradiation. Here, the excellent photocatalyst of chromium doped SrTiO3 with Ti deficiency is synthesized by a solvothermal method. The starting materials of Ti(OC3H7)4, SrCl2.6H2O, and Cr(NO3)3·9H2O were used to create the products under KOH-methanol and oleic acid solution. The Sr/Ti atomic ratios were designed in the range of 1 to 1.67 in.a constant of chromium doping concentration. The powder products were characterized using XRD, UV-Vis DRS, BET, and SEM-EDX. The photocatalytic properties were evaluated using degradation methylene blue (MB) under monochromatic light irradiation of 445 nm (blue LED). The nanoparticles of products with a diameter of 120-200 nm, were successfully prepared. The new visible absorption generated by chromium doping decreased with increasing Sr/Ti atomic ratio. The highest activity of Cr-doped SrTiO3 under visible light irradiation was obtained at 1.25 of Sr/Ti atomic ratio. The dual effect of Cr dopant and Ti deficiency might improve the photocatalytic activity of SrTiO3.