Studies on SnCl2-doped TiO2 photocatalyst for pyrocatechol photodegradation
Résumé
SnCl2-doped TiO2 photocatalyst for pyrocatechol photodegradation aimed to examine the effect of Sn/Ti ratio and H2O2+UVC irradiation. The preparation was carried out by the impregnation and the characterization consisted of WAXD, SEM, and laser particle size. Using 1 mM pyrocatechol in the CSTR with various TiO2 photocatalysts, the remaining pyrocatechol was determined by UV-vis spectrophotometry to calculate % photodegradation. From WAXD results, it was found that SnO2 incorporation to the TiO2 bulk phase but the morphologies did not change. And the particle size changed due to the attraction force of the surface charging. Without H2O2 addition, it showed 15.7% photodegradation by TiSn10UVC compared to 11.37% of TiDark. Thus, UVC was the important factor for photodegradation. With H2O2+UVC irradiation, the maximum photodegradation reached 34.6% by TiSn10HOUVC, but those of HOUVC and TiHOUVC showed 25.0% and 26.5%, respectively. The Sn-doping affected the formation of more hydroxyl free radical from H2O2+UVC irradiation and charge separation. But higher Sn/Ti ration, it gave segregate SnO2 which increased recombination center with the adverse effect on the lower photodegradation. The conclusion revealed that SnCl2-doping with the ratio of Sn/Ti =10 onto TiO2 photocatalyst showed the highest photoactivity with H2O2+UVC irradiation. Moreover, the chemical kinetics is also discussed.