Effect of MCM-41 on the physicochemical properties of Mo and NiMo catalysts and their performance in DBT conversion

The influence of mesoporous materials on the properties and HDS activity of Mo and NiMo catalysts was investigated for supports containing 50 wt.% of MCM-41. A series of catalysts was characterized by different techniques (SBET, TPD-NH3, TPR, SEM, XPS) and tested in dibenzothiophene (DBT) conversion. On the surface of the catalysts containing mesoporous materials, agglomerations of the Mo oxo-species were observed. The presence of MCM-41 in the support visibly weakened the promoting effect of TiO2 on the reducibility of Mo oxides. The results of DBT HDS showed that the NiMo catalyst supported on MCM-41 was not only less efficient than that supported on Al2O3 but also that supported on Al2O3–TiO2. From the distribution of DBT HDS products we can conclude that over catalysts containing MCM-41 the desulphurization of DBT runs mostly via the DDS route.