热老化温度对铈改性水滑石基LNT催化剂NO_(x)吸附-还原性能的影响  

Effect of Thermal Treatment Temperatures on the NO_(x)Adsorption-Reduction Performance of Ce ModifiedHydrotalcite-Based LNT Catalyst

作　　者：石宏志 张许扬 吕刚[1] 宋崇林[1] 李振国[2] 刘双喜[2] 潘锁柱 Shi Hongzhi;Zhang Xuyang;LüGang;Song Chonglin;Li Zhenguo;Liu Shuangxi;Pan Suozhu(State Key Laboratory of Engines,Tianjin University,Tianjin 300072,China;National Engineering Laboratory for Mobile Source Emission Control Technology,China Automotive Technology&Research Center Co.Ltd.,Tianjin 300300,China;School of Automotive and Transportation,Xihua University,Chengdu 610039,China)

机构地区：[1]天津大学内燃机燃烧学国家重点实验室,天津300072 [2]中国汽车技术研究中心有限公司移动源污染排放控制技术国家工程实验室,天津300300 [3]西华大学汽车与交通学院,成都610039

出　　处：《燃烧科学与技术》2023年第2期168-176,共9页Journal of Combustion Science and Technology

基　　金：天津市自然科学基金资助项目(19JCZDJC40100);移动源污染排放控制技术国家工程实验室开放基金资助项目(NELMS2018A15);汽车测控与安全四川省重点实验室开放课题资助项目(QCCK 2020-003)。

摘　　要：采用共沉淀法和分步浸渍法合成了Ce改性水滑石基Pt/BaO/MgAlCe10催化剂,对催化剂进行不同温度热老化处理.通过NO_(x)-TPD、H_(2)-TPSR、XRD、SEM-EDS、in-situ DRIFTs等研究了热老化温度对催化剂的NO_(x)吸附性能、还原性能、晶相结构、微观形貌等的影响.结果表明,催化剂经过600℃和700℃热老化处理后,仍表现出良好的NO_(x)吸附-还原性能;而经过800℃热老化处理后,催化剂表面出现烧结,晶相结构发生明显改变,Pt颗粒发生团聚,催化剂的活性明显下降,NO_(x)存储能力下降了46.8%,NO_(x)转化率由89.53%下降为77.35%.此外,与未处理催化剂相比,经过800℃热老化处理后的催化剂,吸附形成的硝酸盐物种大量减少,催化剂对亚硝酸盐的催化氧化能力被削弱.The co-precipitation method and the distributed impregnation method were employed to generate the Ce modified hydrotalcite-based Pt/BaO/MgAlCe10 catalyst.After thermal pre-treatment under different temperatures,the structure,morphology and NO_(x)adsorption-reduction performance of the catalysts were investigated by NO_(x)-TPD,H_(2)-TPSR,XRD,SEM-EDS and in-situ DRIFTs.Results showed that after the thermal treatment at 600℃and 700℃,the catalyst still showed good NO_(x)adsorption-reduction performance.After the thermal treatment at 800℃,the crystal phase structure of the catalyst changed significantly,and the Pt particles agglomerated,leading to a decrease in the activity of the catalyst.Specifically,the NO_(x)desorption amount decreased by 46.8%,and the NO_(x)conversion efficiency decreased from 89.53%to 77.35%.In addition,after the thermal treatment at 800℃,the amount of nitrate species formed on the catalyst was obviously reduced,and at the same time,the nitrite oxidation capacity of catalyst was weakened as well.

关 键 词：LNT催化剂 水滑石 热老化 NOx吸附-还原 催化剂结构 

分 类 号：TK11[动力工程及工程热物理—热能工程]