Effect of sulfidation temperature on the catalytic activity of MoO3/CeO2–Al2O3 toward sulfur-resistant methanation
Effect of sulfidation temperature on the catalytic activity of MoO3/CeO2–Al2O3 toward sulfur-resistant methanation
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DOI：
10.1016/j.apcata.2013.06.040
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发表时间：
2013-09
影响因子：
5.5
通讯作者：
M. Jiang;Baowei Wang;Jing Lv;Haiyang Wang;Zhenhua Li;Xinbin Ma;Shaodong Qin;Qi Sun
中科院分区：
文献类型：
--
作者：
M. Jiang;Baowei Wang;Jing Lv;Haiyang Wang;Zhenhua Li;Xinbin Ma;Shaodong Qin;Qi Sun
研究了硫化温度对MoO_3/CeO_2-Al_2O_3耐硫甲烷化催化剂活性的影响。用氮气物理吸附(BET)、X射线衍射仪(XRD)、拉曼光谱(RS)、程序升温还原(TPR)、透射电子显微镜(TEM)和X射线光电子能谱(XPS)对催化剂进行了表征。X射线衍射和X射线光电子能谱分析表明，CeO2在500℃以上的硫化温度下发生硫化，Ce3+离子扩散进入催化剂，Al3+离子迁移到催化剂表面。这两个变化提高了催化剂的稳定性，降低了催化活性。随着硫化温度的升高，催化剂的初始催化活性降低。这一下降的原因如下：比表面积减小，CeO2在表面发生不必要的硫化，以及无定形MoS2晶化形成MoS2晶体。最后提出了500℃以上CeO2和MoO2的硫化机理。
The effect of sulfidation temperature on the catalytic activity of MoO3/CeO2–Al2O3toward sulfur-resistant methanation was studied. The prepared catalysts were characterized by N2physisorption (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 CeO2was 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 CeO2on the surface, and the crystallization of amorphous MoS2to form MoS2crystals. Finally, CeO2and MoO3sulfidation mechanisms were proposed for temperatures greater than 500 °C.