New Mo and NiMo catalysts supported on MCM-41/alumina for thiophene hydrodesulfurization

A series of Mo and NiMo catalysts supported on MCM-41-Al2O3 with different amounts of MCM-41 was prepared and tested in the thiophene hydrodesulfurization reaction. In the Mo unpromoted catalysts, an increase in the content of MCM-41 caused a decrease in the thiophene conversion. In contrast, for the NiMo catalysts, where Ni was impregnated first, an increase in the thiophene conversion was observed with the MCM-41 loading. These different trends in HDS catalytic activity of unpromoted and Ni promoted Mo catalysts were related, according to the characterization results, to changes in the dispersion of the Mo phase induced by the presence of the MCM-41 catalyst component, which also change when Ni is impregnated prior to Mo. It was also found for the reaction studied here, that the hydrodesulfurization/hydrogenation ratio increases with MCM-41 content in the NiMo catalysts.