Due to the increasingly stringent regulations of sulfur contents in transportation fuels worldwide, there has been a sharp rise in the demand for costly-effective desulfurization processes.The sulfur species in transportation fuels are generally removed in a catalytic hydrodesulfurization (HDS) process in a modem refinery.Nevertheless, the polyaromatic sulfur compounds,such as dibenzothiophene (DBT) and its alkyl substituted de rivatives, in fuels show dramatically low reactivity.