Studies on SnCl₂-doped TiO₂ photocatalyst for Pyrocatechol Photodegradation

Abstract

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.