Synthesis, Characterization, and Evaluation of Mesoporous MCM-41-supported Molybdenum Hydrotreating Catalysts

Abstract

Mesoporous MCM-41 material with high surface area and narrow pore size distribution was synthesized and used as a support for Mo, CoMo, and NiMo catalysts. The molybdenum loading was varied from 2–14 wt% on MCM-41. On 10 wt% Mo/MCM-41, the promoter Co or Ni concentration was varied from 1–5 wt%. All the catalyst samples were characterized by surface area, low temperature oxygen chemisorption, x-ray diffraction (XRD), and temperature programmed reduction methods. Characterization results show that Mo is well dispersed on MCM-41 up to 10 wt%. The catalytic activities were evaluated for thiophene hydrodesulphurization (HDS), cyclohexene hydrogenation (HYD), and furan hydrodeoxygenation (HDO). All three catalytic functionalities vary in a similar manner to that of oxygen chemisorption as a function of Mo loading, indicating that there is a correlation between oxygen uptake and catalytic sites. The activities of these catalysts were compared with γ-Al₂O₃- and amorphous SiO₂-supported catalysts. It was found that MCM-41-supported Mo catalysts displayed superior activities.

Keywords:

• hydrodesulfurization
• hydrogenation
• low temperature oxygen chemisorption
• MCM-41
• mesoporous materials

ACKNOWLEDGMENT

The authors gratefully acknowledge the support and encouragement that was given by Director, Indian Institute of Petroleum, Dehradun, India.

Notes

^a EMSA (equivalent MoS₂ area), calculated using a factor 0.56616 obtained from pure MoS₂ BET surface area divided by oxygen uptake.

^b EMSA/BET SA × 100.

^c Crystallite size = 5 × 10⁴/ρ × M, where ρ = density of MoS₂ (4.8 g cc⁻¹) and M = EMSA g⁻¹ of MoS₂.