Fabrication of carbon modified visible light active TiO2/MCM-41 nanocomposites for desulfurization of a diesel fuel model

Today, due to the environmental pressures on the sulfur content of gasoline and fuel cell applications, refineries need a very deep desulfurization process 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 removal by visible light irradiation in the presence of C/TiO2@MCM-41 (CTM-41) as a nanophotocatalyst under mild conditions. Photodesulfurization was carried out through oxidation in one phase without using oxidant. For synthesizing CTM-41 nanocomposite, tetra-butylorthotitanate was used as a precursor of Ti. Carbon species were identified in CTM-41 nanocomposite by X-ray photoelectron spectroscopy and UV-Vis spectroscopy. The self-doped carbon in CTM-41 nanocomposite was attributed to the tetra-butylorthotitanate used as a precursor of Ti. In the synthesis process, there was no carbon precursor addition. The formation of two types of carbon (carbonate species and coke-like structure in lattice of TiO2) is responsible for the visible photocatalytic activity of the catalyst. The samples were characterized by X-ray diffraction, FTIR and UV-Vis spectroscopy.