The effect of synergy between Cr₂O₃-CeO₂ and USY zeolite on the catalytic performance and durability of chromium and cerium modified USY catalysts for decomposition of chlorinated volatile organic compounds

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• 作者：Qinqin Huang^a ; ^b ; Zhonghua Meng^a ; Renxian Zhou^a ; ^{zhourenxian@zju.edu.cn}
• 关键词：Cr2O3-CeO2-USY catalysts ; CVOCs decomposition ; Deeper oxidation ability ; Catalytic performance ; Durability
• 刊名：Applied Catalysis B ; Environmental
• 出版年：2012
• 期刊代码：4_09263373
• 类别：ce
• 出版时间：5 April, 2012
• 卷：115-116
• 期：Complete
• 页码：179-189
• 文件大小：1398 K

摘要

The chromium and cerium modified USY zeolite catalysts (Cr₂O₃-CeO₂-USY) were prepared by impregnation method and investigated in terms of catalytic decomposition of dichloromethane (DCM), trichloroethylene (TCE) and 1,2-dichloroethane (DCE). The results show that there are two types of active sites in the catalysts. The acidic site is the active center for dehydrochlorination of CVOCs, and the metallic xoide is the center providing active oxygen species for CVOCs deeper oxidation. The interaction between Cr₂O₃ and CeO₂ species optimizes the concentration ratio of strong acid sites to weak acid sites and improves the mobility of oxygen species over Cr₂O₃-CeO₂-USY catalysts, which is beneficial to the dehydrochlorination and deeper oxidation of chlorinated volatile organic compounds (CVOCs), respectively. Cr₂O₃-CeO₂-USY catalyst with 17.5 wt.%loading of Cr₂O₃ (17.5Cr₂O₃-12.5CeO₂-USY) presents better catalytic performance for CVOCs decomposition along with higher selectivity to HCl and CO₂ formation, which can be due to the higher percentage of strong acidity, more accessible oxygen species, and the stronger synergy between Cr₂O₃-CeO₂ and USY zeolite. In addition, the stronger interaction between Cr₂O₃ and CeO₂, along with the synergy between Cr₂O₃-CeO₂ and USY zeolite over 17.5Cr₂O₃-12.5CeO₂-USY results in less coke deposit, slight HCl attack on the catalysts and improved resistance to chlorination of active components. Therefore, 17.5Cr₂O₃-12.5CeO₂-USY shows the better durability and structure stability during the long term exposure to DCE.