一步法制备高活性NH_(3)-SCR催化剂Cu-SAPO-34:Si含量的影响  

Enhanced NH_(3)-SCR performance over Cu-SAPO-34 prepared by one-step synthesis:effect of Si contents

作　　者：邱爽 肖永厚 刘建辉[1] 贺高红[1,2] QIU Shuang;XIAO Yonghou;LIU Jianhui;HE Gaohong(School of Chemical Engineering,Dalian University of Technology,Panjin Campus,Panjin 124221,Liaoning,China;Liaoning Key Laboratory of Chemical Additive Synthesis and Separation,Panjin Institute of Industrial Technology,Dalian University of Technology,Panjin 124221,Liaoning,China)

机构地区：[1]大连理工大学化工学院盘锦分院,辽宁盘锦124221 [2]大连理工大学盘锦产业技术研究院,辽宁省化学助剂合成与分离重点实验室,辽宁盘锦124221

出　　处：《化工学报》2021年第5期2578-2585,共8页CIESC Journal

基　　金：国家自然科学基金项目(21776028);辽宁省重点研发计划项目(2017308004);辽宁省化学助剂合成与分离重点实验室开放课题重点项目(ZJKF2001)。

摘　　要：NH3选择性催化还原(NH_(3)-SCR)可以有效脱除机动车尾气中的氮氧化物(NO_(x)),开发在中低温下具有高活性且环境友好的低成本催化剂是该技术的关键。以廉价的商品吗啡啉为模板剂,新型络合物Cu-TEPA兼作Cu源和共模板剂,一步水热合成法制备出Cu-SAPO-34分子筛。发现随着Si含量增加,Cu-SAPO-34的结晶度逐渐降低,酸性位点和孤立Cu^(2+)的数量逐渐减少。通过固定床实验系统研究了3种Si含量的Cu-SAPO-34在不同空速下的NH_(3)-SCR性能。结果表明,在气体体积空速(GHSV=40000~120000 h^(−1))下,Cu-SAPO-34均表现出较优异的SCR活性;当SiO_(2)/Al_(2)O_(3)摩尔比为0.2时,具有理想的低温活性(转化率>90%)和较宽的温度窗口(225~425℃)。NH3 selective catalytic reduction(NH3-SCR)can effectively remove nitrogen oxides(NO_(x))from automobile exhaust.The development of low-cost catalysts with high activity at medium and low temperatures and environmentally friendly is the key to this technology.In this work,by utilizing cheap commercial organic structure guide agent morpholine as template,and copper amine complex(Cu-TEPA)as both Cu source and co-templating agent,a low-cost Cu-SAPO-34 molecular sieve was prepared by one-step hydrothermal synthesis method.It was found that with increasing the Si content,the crystallinity of Cu-SAPO-34 gradually decreases,and the acidic sites and Cu^(2+) ions gradually decrease.The NH_(3)-SCR performance of Cu-SAPO-34 with three different Si contents under different space velocities was systematically studied through fixed-bed experiments.The results show that under gas volumetric space velocity(GHSV=40000—120000 h^(−1)),Cu-SAPO-34 shows excellent SCR activity;when the SiO_(2)/Al_(2)O_(3) molar ratio is 0.2,the prepared SCR catalyst,Cu-SAPO-34 has ideal low-temperature activity with the conversion of more than 90% and wide temperature window(225—425℃).This is attributed to the increase of Si addition,the crystallinity of Cu-SAPO-34 gradually decreases,and the precipitation of acidic sites and Cu^(2+) ions gradually decrease.

关 键 词：分子筛 共模板剂 选择性催化还原 催化剂活性 SI含量 

分 类 号：TQ028.8[化学工程]