Research on reaction kinetics of photocatalytic degradation of methylene blue in water solution with SrTiO3 nano film

The nanostructured SrTiO3 film was prepared by sol-gel method and spin-coating process. The X ray diffraction (XRD) analysis shows that the SrTiO3 film is perovskite structure and has the average particle size 25.39nm. The photocatalytic degradation experiments were carried out in methylene blue solutions with the SrTiO3 film. The experimental results show that: the critical concentration of methylene blue solution is slightly higher than 3.289x10(-5)mol/L at which concentration the degradability of film can be most effectively exploited; when the molar concentration is less than the critical concentration, the photocatalytic degradation reaction can be expressed as the first-order reaction kinetics model and the reaction rate decreases with increasing initial concentration; when the concentration is higher than the critical concentration, the degradation reaction is more consistent with the zero-order reaction kinetics model, and the reaction rate remains almost constant with the varied concentration.