The synthesis of nano-sized undoped, Bi doped and Bi, Cu co-doped SrTiO3 using two sol-gel methods to enhance the photocatalytic performance for the degradation of dibutyl phthalate under visible light

Two sol-gel methods (the citric acid gel and the Pechini methods) were used for the preparation of nano-sized undoped, Bi-doped and Bi, Cu co-doped SrTiO3 samples to optimize their properties for the photocatalytic degradation of dibutyl phthalate. The perovskite-like phase was detected for the samples prepared by the citric acid gel method after calcination at 800 °C for 3 h, while in the case of the Pechini method; it was detected after calcination at 800 °C for 9 h. The particle size of the samples prepared by the citric acid gel method is greater than that of the samples prepared by the Pechini method. Cu doping in both methods increased the particle size. Cu doping, Bi doping and Bi, Cu co-doping in both methods shifted the absorption edge to the visible light range as well. The band gap of Bi, Cu co-doped SrTiO3 is smaller than that of Bi doped SrTiO3, which in turn is smaller than that of undoped SrTiO3. The highest removal of the total organic carbon (TOC) of DBP was obtained using a Bi, Cu co-doped SrTiO3 sample prepared by the citric acid gel method. TOC removal of DBP followed pseudo-first order kinetics.