Photocatalytic activity of Zr:SrTiO₃ under UV illumination

SrTiO₃ is a well-known efficient photocatalyst and has various industrial applications such as water or air purification antibacterial agents and self-cleaning surfaces. In this work, pure SrTiO₃ and Zr:SrTiO₃ photocatalysts were prepared by the sol-gel method and then tested by scanning electron microscopy (SEM) and X-ray diffraction, respectively. The crystal phase of Zr:SrTiO₃ shows a typical perovskite structure, in which Ti sites are substituted by Zr atoms. The as-prepared yellow Zr:SrTiO₃ powders were then used as UV photocatalysts. Photocatalytic degradation activity of methylene blue over zirconium-doped SrTiO₃ catalysts was tested under UV illumination. The high activity of Zr:SrTiO₃ was due to the defects of its crystal lattice, thus the energy needed by the semiconductor photoproduction electron transition to the conduction band was smaller than the intrinsic absorption band. The optimal conditions of our experiments are as follows: under 8% doping density of Zr, 10 mg/l initial concentration of methylene blue, 0.15 g photocatalyst dosage, 6.5 of pH value and 4 h of UV illumination time, the degradation rate of methylene blue can reach 93.6%.