物理化学学报 >> 2013, Vol. 29 >> Issue (02): 391-396.doi: 10.3866/PKU.WHXB201212072

催化和表面科学 上一篇    下一篇

铈铬比例对CeO2-CrOx复合氧化物催化剂上1,2-二氯乙烷催化氧化性能的影响

孟中华, 杨鹏, 周仁贤   

  1. 浙江大学化学系, 杭州 310028
  • 收稿日期:2012-10-15 修回日期:2012-12-06 发布日期:2013-01-14
  • 通讯作者: 周仁贤 E-mail:zhourenxian@zju.edu.cn
  • 基金资助:

    国家自然科学基金(21177110), 国家863 重大科研项目(2011AA03A406)和浙江省重点科技创新团队计划资助项目资助

Influence of Ce/Cr Ratio on 2-CrOx Mixed Oxide Catalysts for the Catalytic Oxidation of 1,2-Dichloroethane

MENG Zhong-Hua, YANG Peng, ZHOU Ren-Xian   

  1. Department of Chemistry, Zhejiang University, Hangzhou 310028, P. R. China
  • Received:2012-10-15 Revised:2012-12-06 Published:2013-01-14
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (21177110), Ministry of Science and Technology of China (2011AA03A406), and Program for Zhejiang Leading Team of Science and Technology Innovation, China.

摘要:

采用共沉淀法制备了不同铈铬比例的CeO2-CrOx复合氧化物(Ce/Cr 摩尔比分别为9/1、4/1、2/1、1/1、1/2、1/4、1/8)以及单纯的CeO2和Cr2O3, 并研究了各催化剂对1,2-二氯乙烷(DCE)的催化氧化性能. 结果表明,相较于单纯的CeO2, 不同铈铬比例的复合氧化物催化剂对DCE的催化氧化活性有明显提高, 其中Ce/Cr 摩尔比为2/1的CeO2-CrOx复合氧化物上DCE的氧化活性最好, 且只有极微量的含氯等副产物产生; 随着Ce/Cr 摩尔比减小, 对HCl的选择性有下降的趋势. 通过X射线衍射(XRD)、N2吸附/脱附(BET)、紫外拉曼(UV-Raman)光谱、H2程序升温还原(H2-TPR)、NH3程序升温脱附(NH3-TPD)等实验技术, 研究了铈铬比例对铈铬复合氧化物的物理化学性质的影响. 结果表明, 适当比例Ce-Cr的复合, 形成了结构较稳定的Ce-Cr-O固溶体, 提高了催化剂活性氧物种的流动性, 催化剂表面酸量及强弱酸比例, 从而有利于DCE的吸附活化, 进一步脱氯降解以及深度氧化.

关键词: 催化氧化, 含氯挥发性有机物, 1,2-二氯乙烷, CeO2-CrOx复合氧化物, 铈铬比例

Abstract:

CeO2, Cr2O3, and CeO2-CrOx mixed oxides with molar ratios of Ce to Cr of 9/1, 4/1, 2/1, 1/1, 1/2, 1/4, and 1/8 were prepared by coprecipitation. The catalytic performance of 1,2-dichloroethane (DCE) decomposition was evaluated on all the catalysts. The results indicate that CeO2-CrOx mixed oxides with different Ce/Cr molar ratios showed higher performance for the removal of DCE compared with pure CeO2. The CeO2-CrOx mixed oxide with Ce/Cr molar ratio of 2/1 exhibited the highest catalytic activity of the samples, generating only small amounts of chlorinated by-products during the decomposition of DCE. The selectivity for HCl decreased as the molar ratio of Ce to Cr decreased. The catalysts were characterized by N2 adsorption/desorption, X-ray diffraction (XRD), UV-Raman spectroscopy, hydrogen temperatureprogrammed reduction (H2-TPR), and ammonia temperature-programmed desorption (NH3-TPD) to study the effect of the Ce/Cr molar ratio on the physicochemical performance of the catalysts. An appropriate molar ratio of Ce to Cr formed a more stable Ce-Cr-O solid solution, which increased the mobility of reactive oxygen species, oxidative ability, surface acid content and the ratio of strong acidity, promoting the adsorption, activation and deep oxidation of DCE.

Key words: Catalytic oxidation, Chlorinated volatile organic compound, 1,2-Dichloroethane, CeO2-CrOx mixed oxide, Ce/Cr ratio

MSC2000: 

  • O643