Direct synthesis of mesoporous TiO2 and its catalytic performance in DBT oxidative desulfurization

This paper presents a synthesis process of mesoporous titanium dioxide materials (TiO2) with tetrabutyl titanate as the precursor at ambient conditions. Phosphotungstic acid (PWA) was used as the catalyst, and quaternary ammonium bromide including octadecyltrimethylammonium bromide (STAB), cethyltrimethylammonium bromide (CTAB), (1-tetradecyl)trimethylammonium bromide (TTAB), and dodecyltrimethylammonium bromide (DTAB) as the structure-directing agent. STAB was found to be the best structure-directing agent. The calcined mesoporous TiO2 materials by STAB were characterized by X-ray fluorescent spectroscopy (XRF), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectra, transmission electron microscopy (TEM)) and nitrogen adsorption/desorption measurements. The nitrogen adsorption/desorption isotherms exhibit the characteristics of mesoporous structure. TEM results indicate that the disordered wormhole-like mesostructure without discernible long-range order is formed by the agglomerization of TiO2 nanoparticles. The TiO2 materials exhibit good performance in DBT oxidation. The influence of reaction temperature, catalyst concentration, H2O2 concentration, and initial DBT concentrations on the oxidation of DBT was examined in detail. DBT removal from a 300 ppm dibenzothiophene mixture was as high as 98% within 2 min reaction.