Composite of multi-walled carbon nanotubes (MWNTs) and titanium (IV) oxide (TiO2) were prepared by a heterogeneous gelation method. The activities of the MWNTs/TiO2 composites were evaluated by photocatalytic oxidative desulfurization using dibenzothiophene (DBT), 4,6-dimethyl dibenzothiophene (4,6-DMDBT), n-tetradecane, and commercial diesel under irradiation using a high-pressure Hg lamp. The microstructures of MWNTs/TiO2 composites were characterized by N-2 adsorption, scanning electron microscopy, transmission electron microscope, and X-ray diffraction. It was found that more than 98% of sulfur compounds in commercial diesel were oxidized and removed by the use of the MWNTs/TiO2 composite as a photocatalyst. (C) 2011 Elsevier Ltd. All rights reserved.