Hydrodesulfurization on Supported CoMoS2 Catalysts Ex Ammonium Tetrathiomolybdate: Effects of Support Morphology and Al Modification Method

In this work, Co-promoted MoS2 catalysts supported on Al-modified mesoporous silica (HMS and SBA-16) have been prepared by the decomposition of ammonium tetrathiomolybdate and cobalt nitrate precursors in a H2S/H-2 gas mixture. The effects of the support morphology and Al incorporation method (one-pot synthesis vs. support's grafting) on the catalyst activity were investigated in the reaction of hydrodesulfurization (HDS) of dibenzothiophene (DBT) conducted in a high-pressure batch reactor at 350 degrees C and total H-2 pressure of 3.3 MPa. The physical and chemical characterization of the oxide precursors and spent catalysts was studied by a variety of several techniques (N-2 adsorption-desorption, XRD, SEM, EDS, Al-27 MAS NMR, Raman, TG/DTA and DRS UV-vis). The MoS2 phase of all catalysts exhibits similar size (about 2.8 nm) and stacking layers (4). Activity tests showed that CoAT/HMS-Al was most active and selective toward direct desulfurization (DDS) reaction pathway among the catalysts studied. Its catalytic response was similar to that of CoMo/gamma-Al2O3 catalyst activated by reductive sulfiding. A linear correlation was found between DBT conversion at a reaction time of 5 h and the specific surface area and mean pore diameter of the catalysts. The best DBT HDS activity showed CoAT/HMS-Al catalyst having the best textural properties among the catalysts studied. Modification of SBA-16 with Al3+ ions by the one-step synthesis method rendered the catalyst more active in the HDS reaction than its modification by grafting.

Automated summary

In this study, Co-promoted MoS2 catalysts supported on Al-modified mesoporous silica have been prepared and their catalytic activity in the hydrodesulfurization (HDS) reaction of dibenzothiophene (DBT) was investigated. The results showed that the support morphology and Al incorporation method have a significant impact on the catalyst's activity.