Effect of SO2 on the performance of Co/MOR catalyst for the selective catalytic reduction of NO by CH4
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摘要: 考察了富氧条件下SO2存在对丝光沸石负载的钴催化剂（Co/MOR）上甲烷选择催化还原NO的反应性能的影响，并采用NO程序升温脱附(NO-TPD)、X射线衍射(XRD)、H2程序升温还原(H2-TPR)和紫外可见漫反射光谱(UV-vis DRS)等技术对反应前后催化剂的NO吸附性能和结构特征进行了表征。结果表明，受SO2气氛的影响，Co/MOR催化剂上NO转化率在低于550℃时下降较大，但在高于600℃时SO2的影响不明显，而且这种影响是可逆的。SO2的存在抑制了NO在催化剂活性位上的吸附，同时在反应过程中促进了CoO物种的生成，导致催化剂活性中心数减少、催化剂活性下降。Abstract: The selective catalytic reduction (SCR) of NO by CH4 in the presence of SO2 was investigated over the catalyst cobalt supported on Mordenite (Co/MOR); both the fresh and spent catalysts were characterized by temperature-programmed desorption of NO (NO-TPD), X-ray diffraction (XRD), H2 temperature-programmed reduction (H2-TPR), and UV-vis diffuse reflectance spectroscopy (UV-vis DRS). The results indicated that the presence of SO2 in the feed leads to a decrease of NO conversion at a temperature below 550℃; however, this influence is not evident at a temperature above 600℃. Moreover, the negative effect of SO2 on the NO conversion is reversible over the Co/MOR catalyst. SO2 may inhibit the adsorption of NO on the active sites and promote the formation of CoO during the reaction, which leads to a decrease of the active sites and the activity of Co/MOR for the SCR of NO.
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