Effect of sulfidation temperature on the catalytic activity of MoO3/CeO2–Al2O3 toward sulfur-resistant methanation

Authors: Minhong Jiang, Baowei Wang, Jing Lv, Haiyang Wang, Zhenhua Li, Xinbin Ma, Shaodong Qin, Qi Sun

Abstract:
The effect of sulfidationtemperature onthe catalytic activity of MoO₃/CeO₂–Al₂O₃ towardsulfur-resistant methanation was studied. The prepared catalysts were characterized by N₂ physisorption (BET), X-ray diffraction (XRD), Raman spectroscopy (RS), temperature-programmed reduction (TPR), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The XRD and XPS results indicated that CeO₂ was sulfided at sulfidation temperatures above 500^◦C. During sulfidation at 500 ^◦C or above, Ce³⁺ ions diffused into the catalyst, and/or Al³⁺ ions migrated to the surface of the catalyst. These two changes enhanced catalyst stability and decreased catalytic activity. The initial catalytic activity decreased as the sulfidation temperature increased. This decrease occurred for the following reasons: the decrease in BET surface area, the undesired sulfidation of CeO₂ on the surface, and the crystallization of amorphous MoS₂ to form MoS₂ crystals. Finally, CeO₂ and MoO3 sulfidation mechanisms were proposed for temperatures greater than 500 ◦C.

Keywords:
Sulfidation temperature
Catalytic activity
MoO₃/CeO₂–Al₂O₃ catalyst
Sulfur-resistant methanation

Published in: Applied catalysis A: General  (Volume 466, Pages 1-314, 10 September 2013)

Publisher: Elsevier  

ISSN Information: 0926-860X

Effect of sulfidation temperature on the catalytic activity of MoO3/CeO2–Al2O3 toward sulfur-resistant methanation

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