Different modes of pore blockage by coke deposit over Mo/(Al-)MCM-41 and Mo/(Al-)MCM-48 catalysts for hydrodesulfurization

Abstract

M41S materials contain mesopores large enough to expand the scope of application as molecular sieve catalysts, since they can be endowed with acidity by incorporating trivalent cation such as Al3+. While MCM-41 based catalysts are reported to show good catalytic activities for many types of reactions, they are vulnerable to coke deposit due to pore blockage. MCM-48 with two independent three-dimensional channel systems could be expected to be much more resistant to pore blockage. MCM-41 and MCM-48 were chosen to prepare the supported molybdenum catalysts, which were used for the hydrodesulfurization of thiophene. The coke deposit resulted in different deactivation obviously due to the difference in channel connectivity between MCM-41 and MCM-48. Mo/MCM-48 with biporous channels showed a better stability than Mo/MCM-41 with unidimensional channels, which can be explained by different modes of pore blockage.