Effect of ordered mesoporous Zr SBA-15 support on catalytic functionalities of hydrotreating catalysts 2. Variation of molybdenum and promoter loadings

• ZrSBA-15 support is synthesized by direct addition of Zr to the synthetic mixture.
• Retainment of mesoporous structure of SBA-15 even after deposition of Mo and promoter.
• The oxygen uptakes and catalytic activities for HDS and HYD passed through a maximum at 8 wt% Mo loading.
• ZrSBA-15 supported Mo catalysts displayed superior activities for both HDS and HYD functionalities.
• The promoted catalysts (Co and Ni) showed maximum activity at 3 wt% loading for both the functionalities.

ZrSBA-15 support with Si/Zr = 20 containing majority of Zr in framework positions is synthesized by direct addition of Zr to the synthetic mixture. Various catalysts containing 2–12 molybdenum loading were prepared by incipient wetness impregnation. Using 8 wt% Mo catalysts Co and Ni promoted catalysts were prepared with 1–5 wt% promoter loading. All the Mo, CoMo, NiMo catalysts were characterized by N2 adsorption–desorption, low angle and wide angle XRD, temperature programmed reduction (TPR) and oxygen chemisorption on sulfide catalysts. The catalytic activities for thiophene HDS, cyclohexene HYD were evaluated on sulfide catalysts at 400 °C. The oxygen uptakes and catalytic activities for HDS and HYD passed through a maximum at 8 wt% loading. The H2/Mo ratios obtained as a function of Mo loading also passed through a maximum at the same temperature. The promoted catalyst showed maximum activity at 3 wt% loading for both the functionalities. These results will be discussed in the light of characterization results in terms of reducibility, dispersion and anion vacancy variation with Mo and promoter loading.

Oxygen uptakes correlate well with HDS as well as HYD indicating that oxygen chemisorption is not specific any one of the functionalities but measures general state of dispersion of MoS2 in supported catalysts.Figure optionsDownload high-quality image (116 K)Download as PowerPoint slide