Cu-SAPO-44分子筛的制备及其C_(3)H_(6)-SCR脱硝性能  

Preparation and de-NO_(x) performance of C_(3)H_6-SCR over Cu-SAPO-44 catalyst

作　　者：周皞[1] 张恒 温妮妮 王旭瑞 徐璐 李玮[1] 苏亚欣[2] ZHOU Hao;ZHANG Heng;WEN Nini;WANG Xurui;XU Lu;LI Wei;SU Yaxin(Changzhou Institute of Engineering Technology,Changzhou 213164,Jiangsu,China;School of Environmental Science and Engineering,Donghua University,Shanghai 201620,China)

机构地区：[1]常州工程职业技术学院,江苏常州213164 [2]东华大学环境科学与工程学院,上海201620

出　　处：《化工进展》2023年第3期1373-1382,共10页Chemical Industry and Engineering Progress

基　　金：江苏省自然科学基金(BK20181161);国家自然科学基金(52276103);江苏省高等学校优秀科技创新团队项目(2019)。

摘　　要：分别采用以硫酸铜为铜源、环己胺为单模板剂,以硫酸铜为铜源、环己胺为模板剂、聚乙二醇(PEG2000)为协同模版剂,以Cu-TEPA(四乙烯五胺)和环己胺共模板剂3种制备方法,一步水热合成Cu-SAPO-44分子筛催化剂,用于选择性催化丙烯还原柴油机车尾气氮氧化物(C_(3)H_(6)-SCR)。采用X射线衍射、N_(2)吸附-脱附、扫描电镜、紫外可见光谱、H_(2)程序升温还原和NH_(3)程序升温脱附等方法对催化剂进行表征,考察不同模板剂对Cu-SAPO-44物理化学特性和C_(3)H_(6)-SCR性能的影响。结果表明,以Cu-TEPA为模板剂制备Cu-SAPO-44时,Cu-TEPA既作为结构导向剂又提供活性铜物种,合成的分子筛结晶度高,铜负载量大,具有更多的活性Cu^(2+)和丰富的表面酸性,为C_(3)H_(6)-SCR反应提供了大量的活性位点,因此具有最佳的脱硝性能。在含有10%O_(2)和5%H_(2)O的稀薄燃烧烟气条件下,在300~350℃可实现90%以上的NO_(x)转化率和N_(2)选择性。而引入PEG2000对提高Cu-SAPO-44分子筛的脱硝效果不明显。经过50h的持续脱硝反应测试,Cu-SAPO-44(T)催化剂表现出良好的反应稳定性。Cu-SAPO-44 catalysts were synthesized by three preparation methods:copper sulfate as copper source and cyclohexylamine as single template;copper sulfate as copper source,cyclohexylamine as template and polyethylene glycol (PEG2000) as synergistic template;and Cu-TEPA(tetraethylenepentamine) and cyclohexylamine as co-templates.These catalysts were used for selective catalytic reduction of nitric oxide with propylene (C_(3)H_6-SCR) under diesel engine exhaust.These zeolites were characterized by X-ray diffraction (XRD),N_(2) adsorption-desorption,scanning electron microscopy(SEM),UV-vis spectroscopy (UV-vis),H_(2) temperature-programmed reduction (H_(2)-TPR) and NH_(3) temperature-programmed desorption (NH_(3)-TPD).The results showed that Cu-TEPA template not only acted as structure directing agent,but also provided active copper species.Then,Cu-SAPO-44 catalyst prepared with Cu-TEPA template had high crystallinity,large copper loading,more active Cu^(2+)ions and rich surface acidity,which provided a large number of active sites for C_(3)H_(6)-SCR reaction.Therefore,it had the best de-NO_(x) performance,which could obtain more than 90%NO_(x) conversion and about 90%N_(2) yield at 300—350℃ under lean burning condition containing 10%O_(2) and 5%H_(2)O.However,the introduction of surfactant PEG2000 had little effect on improving the activity of Cu-SAPO-44 catalyst.The Cu-SAPO-44(T) catalyst indicated appropriate reaction stability in long term test of 50hours.

关 键 词：模板剂 Cu-SAPO-44 选择性催化还原 一氧化氮 丙烯 

分 类 号：X511[环境科学与工程—环境工程]