Structure, acidity and activity of CuOx/WOx–ZrO2 catalyst for selective catalytic reduction of NO by NH3
Structure, acidity and activity of CuOx/WOx–ZrO2 catalyst for selective catalytic reduction of NO by NH3
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DOI：
10.1016/j.jcat.2010.01.025
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发表时间：
2010-04
影响因子：
7.3
通讯作者：
Zhichun Si;D. Weng;Xiaodong Wu;Jia Li;Guo Li
中科院分区：
文献类型：
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作者：
Zhichun Si;D. Weng;Xiaodong Wu;Jia Li;Guo Li
在共沉淀法制备的WOx-ZrO2载体上浸渍不同量的铜，制备了一系列CuOx/WOx-ZrO2催化剂，并用X射线衍射仪、BET、XPS、NH3/NO化学吸附、NH3-TPO和NH3-SCR活性测定对催化剂进行了表征。在10wt%CuOx/WOx-ZrO2催化剂上，获得了较宽的温度范围(200-320℃)，转化率不超过80%。催化剂对氨氧化和NH3-SCR反应的活性和选择性取决于Lewis酸位和Brnsted酸位的强度和数量，而Lewis酸位和Brnsted酸位的强度和数量受WOx-ZrO2固溶体的形成和铜氧化物的加入的影响。提出了CuOx/WOx-ZrO2催化剂上SCR反应的两种不同反应路线：低温(<；200℃)下的“氨-NO2路线”和高温(>；250℃)下的“胺-NO/NO2”路线。
A series of CuOx/WOx–ZrO2catalysts were synthesized by impregnating different amounts of copper on the coprecipitated WOx–ZrO2support and were characterized by XRD, BET, XPS, NH3/NO chemisorption, NH3-TPO and NH3-SCR activity measurements. A wide temperature range (200–320°C) in which NO conversion exceeds 80% is achieved on the 10wt.% CuOx/WOx–ZrO2catalyst. The activity and selectivity of the catalysts for ammonia oxidation and NH3-SCR reaction are determined by the strength and amount of Lewis acid sites and Brønsted acid sites, which are adjusted by the formation of WOx–ZrO2solid solutions and the addition of copper oxides. Two different reaction routes, “ammonia–NO2route” at low temperatures (<200°C) and “amine–NO/NO2” at high temperatures (>250°C), are presented for SCR reaction over CuOx/WOx–ZrO2catalysts.