Hydrodesulfurization of Dibenzothiophene Using Lanthanum Doped CoMoS2

摘要

Hydrodesulfurization (HDS) is a technique used in petrochemical industry for the removal of sulfur from crude oil. Using dibenzothiophene (DBT) as a target molecule and CoMoS2 catalysts doped with various concentrations of lanthanum were studied for catalytic activity in the removal of DBT from solution. Catalysts were synthesized using ammonium tetrathiomolydate, cobalt chloride and lanthanum nitrate under a solvothermal decomposition in decalin at 350 °C with H2 gas at 160 psi. To evaluate decomposition effects, a second set of catalyst precursors were decomposed in a tube furnace at 450 °C under a constant flow of 10%/90% H2/Ar. Characterizations of the catalysts were performed prior to and following one catalytic cycle using XRD, SEM/EDX and XPS. Catalytic cycles were performed in DBT/decalin solutions and analyzed using a combination of GC-FID and GC-MS. The introduction of lanthanum enhanced catalytic activity of the catalysts at concentrations of 10--25%. However, a 5%, lanthanum doping poisoned the catalyst. In addition, the studies showed the 25% doped catalyst decomposed at 450°C exhibited higher catalytic activity than those decomposed solvothermally.