Controllable preparation of highly dispersed TiO2 nanoparticles for enhanced catalytic oxidation of dibenzothiophene in fuels

The aggregation of nanoparticle catalysts is one of the main problems in catalytic reactions. In this study, a series of TiO 2 nanoparticle catalysts with various dispersions were prepared and applied in the catalytic oxidation of dibenzothiophene (DBT) systems. Compositions and structures of the as-prepared samples were analyzed by means of wide-angle X-ray diffraction, Raman and X-ray photoelectron spectroscopies. The dispersions of TiO 2 nanoparticles were controlled by calcining at various temperatures and verified using transmission electron microscopy. It was found that the activities of TiO 2 nanoparticles in the catalytic oxidation of DBT were positively correlated with the dispersions. TiO 2 nanoparticles calcined at 500 °C (500-TiO 2 ) showed the best catalytic activity and the oxidation of DBT reached 99.8% under mild conditions. Based on the results of GC–MS analysis, radical trapping experiments and electron spin resonance spectra, • O 2 − radicals were proved to be the main active species in the oxidation process, and a mechanism is proposed. Meanwhile, the recycling performance of 500-TiO 2 was investigated, and no obvious decrease was observed after six recycles.