碱土金属钙沉积对Mn-Ce/TiO2低温SCR催化剂脱硝性能的影响 |
摘要点击 2429 全文点击 1839 投稿时间:2014-05-12 修订日期:2014-06-27 |
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中文关键词 低温选择性催化还原 锰铈钛复合氧化物 碱土金属 钙盐沉积 催化剂中毒 |
英文关键词 low-temperature SCR Mn-Ce/TiO2 catalyst alkali earth metal Ca deposition catalyst poisoning |
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中文摘要 |
本研究采用浸渍法分别制备CaCl2、CaCO3和CaSO4这3种钙盐前驱体沉积的Mn-Ce/TiO2催化剂,通过分析催化剂活性与催化剂理化特性之间的关系,考察碱土金属钙沉积对Mn-Ce/TiO2低温SCR催化剂脱硝性能的影响. 结果表明,钙的加入会导致催化剂中毒,且不同钙前驱体掺杂对催化剂中毒效应不同. CaCO3的沉积对Mn-Ce/TiO2催化剂脱硝效率的影响最小,而CaCl2沉积对催化剂活性抑制作用最为强烈. 通过比表面积测试(BET)、X射线光电子能谱(XPS)、X射线晶体衍射(XRD)、程序升温脱附(TPD)等方法对不同催化剂进行表征发现,催化剂的晶型变化、孔道结构破坏、表面活性元素及酸性点位的减少是催化剂中毒的主要原因. |
英文摘要 |
Calcium carbonate (CaCO3), calcium sulfate (CaSO4), and calcium chloride (CaCl2) were chosen as the precursors to prepare the Ca salts deposited Mn-Ce/TiO2 catalysts through an impregnation method. The influence of Ca on the performance of the Mn-Ce/TiO2 catalyst for low-temperature selective catalytic reduction of NO by NH3 was investigated. Experimental results showed that Ca salts had negative effects on the activity of Mn-Ce/TiO2 and the precursors of Ca salts also affected the catalytic activity. The precursor CaCl2 had a greater impact on the catalytic activity, while CaCO3 had minimal effect. The samples were characterized by Brunner-Emmet-Teller measurements (BET), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and NH3 temperature programmed desorption (NH3-TPD). The characterization results indicated that the significant changes in physical and chemical properties of Mn-Ce/TiO2 were observed after Ca was deposited on the catalysts. The significant decreases in surface areas and NH3 adsorption amounts were observed after Ca was deposited on the catalysts, which could be considered as the main reasons for the deactivation of Ca deposited Mn-Ce/TiO2. |