HDS performance of NiMo catalysts supported on nanostructured materials containing titania

• NiMo catalysts supported on titania-containing nanostructured materials were studied.
• Catalytic activity was tested in HDS of dibenzothiophene (DBT) and 4,6-dimethyl-DBT.
• Support effect on HDS activity and selectivity of NiMo catalysts was observed.
• All synthesized catalysts showed higher activity in 4,6-DMDBT HDS than NiMo/γ-Al2O3.
• NiMo/NT catalysts showed high activity for 4,6-DMDBT HDS with low H2 consumption.

In the present work, NiMo catalysts supported on titania-containing materials of the SBA family (Ti-SBA-15 and Ti-SBA-16) and on titania nanotubes of different pore diameters were prepared with the aim of selecting the most promising catalysts for deep hydrodesulfurization (HDS) of gas oil. Supports and catalysts were characterized by nitrogen physisorption, XRD, temperature programmed reduction, ammonia TPD, UV–vis DRS and scanning electron microscopy (SEM-EDX). Sulfided catalysts were characterized by HRTEM and tested in the simultaneous HDS of dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT). For comparison purposes, a conventional NiMo/γ-Al2O3 catalyst was used. In HDS of DBT, all catalysts supported on titania-containing nanostructured materials showed similar activity as the NiMo/γ-Al2O3 reference, but in HDS of 4,6-DMDBT their activities were about twice higher than that of NiMo/γ-Al2O3. Regarding selectivity, for DBT HDS, the presence of titania in the supports resulted in an increase in the proportion of CHB product, whereas for 4,6-DMDBT different behavior was observed. Thus, NiMo catalysts supported on Ti-SBA-15 and Ti-SBA-16 showed similar selectivity as the NiMo/γ-Al2O3. On the contrary, the catalysts supported on titania nanotubes allowed reaching high conversions of 4,6-DMDBT with a much lower proportion of hydrogenated products, which is an interesting result not observed by us previously.

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