Hydrodesulfurization over NiMo Catalysts Supported on Yolk-shell Silica Materials with Controllable Cavity Size

摘要

Novel yolk-shell (YS) mesoporous silica materials with different cavity sizes were successfully synthesized. Aluminium was bridged into the yolk-shell framework of silica by a post synthesis method to improve the acidity of YS, namely Al-YS. The corresponding NiMo/Al-YS catalysts were also fabricated and used in the hydrodesulfurization (HDS) reaction of dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT). The NiMo/Al-YS catalyst with the cavity size of 154 nm (NiMo/Al-YS-154) exhibits the superior conversions of DBT (99.2 %) and 4,6-DMDBT (96.1 %) at 340 degrees C, 4.0 MPa, 10 h(-1), highest k(HDS) (13.4x10(-4 mol g-1) h(-1) for DBT and 8.9 mol g(-1) h(-1) for 4,6-DMDBT) and highest TOF for DBT (3.7 h(-1)) and 4,6-DMDBT (2.3 h(-1)) among the investigated catalysts. The appropriate cavity size of NiMo/Al-YS-154 catalyst plays the key role in obtaining its superior HDS catalytic performance. Furthermore, the possible reaction networks of DBT and 4, 6-DMDBT HDS over NiMo/Al-YS-x catalysts were also presented.