Tuning Effect of the Zeolite Brønsted Acidity on the FeZn Bimetallic Hydrodesulfurization Catalyst

The promotion of hydrodesulfurization (HDS) activity of supported Fe catalysts by regulation of the Bronsted (B) acid sites on supports has not been extensively investigated. In this paper, a Y-type zeolite-doped gamma-Al2O3 support having different SiO2/Al2O3 ratios was utilized to demonstrate the influence of B acid sites on the catalytic activity of supported FeZn catalysts in HDS. It was found that an appropriate density of Bronsted acid sites could prompt not only the dispersion of active metal species but also the activity in HDS of dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT). Besides, the presence of an appropriate B acid site density could reduce the interaction between the support and active metal sites, decrease the reduction temperature of the metal oxide in the catalyst, and thus favor the sulfidation of as-prepared catalysts. In addition, the catalyst having B acid sites could facilitate the product selectivity through direct desulfurization (DDS) and isomerization (ISO) routes during HDS of DBT (or 4,6-DMDBT).