Photocatalytic oxidative desulfurization of model fuel over visible light-active Cu-impregnated carbon-doped TiO2

TiO2 has a high bandgap energy with light absorption in the ultraviolet region making it non-efficient under visible-light. The purpose of the present work is to modify the properties of TiO2 by adding carbon and copper to its structure, in order to acquire an active nanostructure for photocatalytic oxidative desulfurization of model liquid fuel under visible light irradiation. In this regard, carbon doped TiO2 was first synthesized by a hydrothermal method, then Cu (II) were impregnated on carbon doped TiO2. The resulting photocatalysts were characterized by techniques such as XRD, N2 physisorption, SEM, TEM, DRS, EDX, PL, and FTIR. The effects of parameters including calcination temperature (200–600 °C), Cu loading (0.5–5 wt%), amount of H2O2 oxidant (0–3 ml), the volume ratio of solvent to fuel (0.5–2), initial concentration of DBT (100–1000 mg/ml) and the catalyst dosage (1–4 g/l) on the performance of the photocatalyst were subsequently studied. The best performance (98.27% of DBT removal efficiency) was obtained for 0.5Cu-CT in presence of 0.1 ml H2O2, solvent to fuel ratio of 1, catalyst dosage of 2 g/l, and initial DBT concentration of 250 mg/l 0.5Cu-CT demonstrated the best photocatalytic activity due to low electron/hole recombination, high BET surface, and appropriate bandgap energy.