铈锆固溶体催化剂催化燃烧甲苯的研究

Combustion of toluene catalyzed by ceria-zirconia solid solutions

采用3种不同方法制备了铈锆固溶体催化剂,考察了铈锆摩尔比、焙烧温度、空速对催化剂催化甲苯活性的影响,采用XRD、BET、SEM检测了催化剂的结构形貌。结果表明,溶胶-凝胶法制得的催化剂去除甲苯效率最高。铈锆固溶体催化剂的铈锆摩尔比为0.6∶0.4时,焙烧温度为550℃,出现最大的比表面积为87.3 m2/g,此时催化甲苯的效率最高。Ce0.6Zr0.4O2催化剂连续反应120 h仍能保持较高的催化活性。通过XRD分析,Zr4+能进入二氧化铈晶格中形成立方萤石结构的铈锆固溶体,增加了晶格缺陷,提高了二氧化铈催化活性。

The ceria-zirconia solid solution catalysts are prepared by three different methods. The influences of Ce-Zr molar ratio, calcination temperature and space velocity on catalytic activity of combustion of toluene are investigated. Meanwhile,the morphology and structure of catalyst are characterized by XRD, BET and SEM. The results show that the catalyst obtained from sol-gel method has the highest toluene removal rate. The biggest specific surface area （87. 3 m2/g） of ceria-zirconia solid solution catalyst can be obtained when the molar ratio of Ce-Zr is 0. 6： 0. 4 and the calcination temperature is 500 ℃, which contributes to its highest catalytic activity of toluene combustion. The Ce0. 6 Zr0. 4 02 catalyst remains high relative activity even after 120 hour continuous reaction. XRD result indicates that Zr4＋ can merge into ceria lattice and form cubic fluorite-like ceria zirconia solid solution which creates more lattice defect and improves ceria catalytic activity.