Tio2–based mixed oxide photocatalysts for oxidative desulfurization

This work reports the synthesis of TiO2-WO3 and TiO2-SiO2 composites using sol-gel method. The prepared composites were used as catalysts in photocatalytic oxidative desulfurization of dibenzothiophene (DBT). TiO2-SiO2 composites were also prepared by wet impregnation method to study the effect of synthesis methods on the photocatalytic efficiency. The prepared materials were characterized by XRD, FTIR, N2 adsorption-desorption, SEM, NH3-TPD, DRUV and PL analysis. The catalytic results for WO3-TiO2 composites show that the charge recombination was less occurred which was beneficial for enhancing the photocatalytic efficiency. Interestingly, WO3-TiO2 composites could be activated under visible irradiation and most of them showed higher photocatalytic activity than bulk TiO2. It was found that the 20% loading amount of WO3 was the optimal value to obtain the highest photocatalytic efficiency. For TiO2-SiO2 composites, TiO2 was highly dispersed on the large surface of SiO2 leading to the increase in surface area of TiO2-SiO2 composites, which could facilitate the adsorption of the oxidized products generated from the oxidative desulfurization process. The TiO2-SiO2 composites prepared by sol-gel method exhibited better performance than those prepared by wet impregnation method. Among the prepared TiO2-SiO2 composites, 15TiO2-SiO2 (SG) showed the highest performance in sulfur removal with the sulfur uptake of 5.53 mg/g-TiO2 loading.