Today, due to the environmental pressures on sulfur content of gasoline and fuel cell applications; refinery needs a very deep desulfurization to reach the ultra-low sulfur diesel(ULSD,1 ppm). In this research, dibenzothiophene (DBT) in n-octane solution as a diesel fuel model was completely converted into biphenyl by visible light irradiation in the presence of C/TiO2@MCM-41 photonanocatalyst under ambient conditions. For the first time, the conversion was carried out through oxidation in one phase without using oxidant. In the synthesis of TiO2@MCM-41, tetrabutylortotitane was used as a precursor of Ti. After characterization,carbon species were identified in TiO2@MCM-41 by x-ray photoelectron spectroscopy and UV-Vis analysis. Therefore, the synthesized catalyst was named as C/TiO2@MCM-41. The self-doped carbon in TiO2@MCM-41was attributed to the tetrabutylortotitaneused as a precursor of Ti. In the synthesis process, there was no addition for the precursor of carbon. The formation of two types of carbon (carbonate species and substituting carbon in lattice of TiO2) is responsible for the visible photocatalytic activity of the nanocatalyst.The samples were characterized by powder X-ray diffraction, FTIR and UV-Vis spectroscopy. The nitrogen adsorption-desorption was carried out at 77 K. The GC-MASS analysis confirmed the convert of DBT to biphenyl. The mechanism was claimedbased on the experimental results. The hole and hydroxyl radicalas reactive species had a key role in the photocatalytic desulfurization process.

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