Co物种调控增强Co/SSZ-39催化剂的低温CH_(4)-SCR活性  

Regulating Co Species over Co/SSZ-39 Catalyst to Enhance the Low-temperature CH_(4)-SCR Activity

作　　者：安素峰 汪鹏 王宽岭 王学海 李宝忠 郭新闻[2] AN Sufeng;WANG Peng;WANG Kuanling;WANG Xuehai;LI Baozhong;GUO Xinwen(SINOPEC(Dalian)Research Institute of Petroleum and Petrochemicals,Dalian 116045,China;Chemical Engineering Institute,Dalian University of Technology,Dalian 116024,China)

机构地区：[1]中石化(大连)石油化工研究院有限公司,大连116045 [2]大连理工大学化工学院,大连116024

出　　处：《高等学校化学学报》2024年第8期89-96,共8页Chemical Journal of Chinese Universities

基　　金：国家自然科学基金(批准号:22202029,22372022,22372169)资助.

摘　　要：以小孔SSZ-39分子筛为载体,采用浸渍法和离子交换法制备了不同钴(Co)含量的Co/SSZ-39催化剂,利用X射线衍射仪、透射电子显微镜、氮气吸附-脱附和氢气程序升温还原等技术对Co/SSZ-39催化剂进行表征测试,对比了不同制备方法和不同Co负载量催化剂对CH_(4)选择催化还原NO反应(CH_(4)-SCR)性能的影响.结果表明,采用离子交换法经单次离心洗涤,可以调控分子筛上Co物种的类别,制备的Co-SSZ-39-S催化剂同时富含离子态Co位点和高分散的活性CoOx物种,可以促进CH_(4)低温适度活化,提高低温条件下CH_(4)选择性还原NOx的性能.将制备的催化剂应用于CH_(4)-SCR反应,在较低反应温度(400℃),NO/CH_(4)摩尔比为1∶1时,NO转化率可达68%,CH_(4)转化率可达82%;NO/CH_(4)摩尔比为1∶2时,NO转化率为76%,CH_(4)转化率为81%,且转化率在50 h内保持稳定.该催化剂可实现NOx和CH_(4)的协同去除.Co/SSZ-39 catalyst with different cobalt(Co)content was prepared by impregnation method and ion exchange method using small-pore SSZ-39 molecular sieve as carrier.The Co/SSZ-39 catalysts were characterized by X-ray diffraction(XRD),transmission electron microscopy(TEM),nitrogen adsorption-desorption and H2 tempera-ture programming reduction(H2-TPR).The effects of different preparation methods and catalysts with different Co loads on the performance of CH_(4) selective catalytic reduction of NO(CH_(4)-SCR)were compared.The characterization results showed that the classification of Co species on SSZ-39 can be regulated by ion exchange method along with a single centrifuge washing.The Co/SSZ-39-S catalyst have both ionic Co sites and highly active CoOx species.The highly active CoOx species could promote moderate activation of CH_(4) at low temperature and improve the selective NOx reduction performance of CH_(4) at low temperature.When applied to CH_(4)-SCR reaction,the catalyst prepared by this method can achieve 68%NO conversion and 82%CH_(4) conversion at a lower reaction temperature of 400℃(the molar ratio of NO and CH_(4) is 1∶1).When the molar ratio of NO and CH_(4) is 1∶2,the catalyst can achieve 76%NO conversion and 81%CH_(4) conversion,and the conversion rate remains stable within 50 h.The catalyst can realize the collaborative removal of NOx and CH_(4).

关 键 词：CH_(4)-SCR Co/SSZ-39 甲烷低温活化 离子交换法 

分 类 号：O643.3[理学—物理化学]