SBA-15 supports modified by Ti and Zr grafting for NiMo hydrodesulfurization catalysts

摘要

A series of Ti-and Zr-containing mesoporous SBA-15 supports and their respective NiMo catalysts were prepared to study the effect of the Ti and Zr loading into the support on the characteristics of Ni and Mo surface species and their catalytic activity in the 4,6-dimethyldibenzothiophene hydrodesulfurization (HDS).Ti and Zr-containing SBA-15 solids with different metal loading (up to 19 wt.% of TiO_2 or 22 wt.% of ZrO_2) were prepared by chemical grafting.The solids prepared were characterized by N_2 physisorption,X-ray diffraction (XRD),UV-vis diffuse reflectance spectroscopy (DRS),temperature-programmed reduction (TPR),chemical analysis and HRTEM.The results show that Ti-and Zr-SBA-15 supports with highly dispersed Ti and Zr species can be obtained without substantial loss of SBA-15 characteristics.Zr grafted species showed somewhat better dispersion on the SBA-15 surface than the corresponding Ti counterparts.It was found that TiO_2 and,especially,ZrO_2 incorporation in the SBA-15 support leads to stronger interaction of Mo and Ni species with the support providing better dispersion to the oxidic and sulfided metal species (XRD,TPR,HRTEM).NiMo catalysts supported on Ti-and Zr-containing SBA-15 showed high activity in 4,6-dimethyldibenzothiophene HDS.It can be concluded therefore that SBA-15 materials grafted with Ti or Zr species show promising features as supports for Mo-based hydrotreating catalysts.