物理化学学报 >> 2015, Vol. 31 >> Issue (6): 1153-1161.doi: 10.3866/PKU.WHXB201504145

催化和表面科学 上一篇    下一篇

稀土掺杂对氯化氢氧化制氯气CuO-CeO2-SiO2催化剂结构和性能的影响

谢兴星1,2, 费兆阳1,2, 邹冲1,2, 李郑州1,2, 陈献2, 汤吉海2, 崔咪芬2, 乔旭1,2   

  1. 1 南京工业大学材料化学工程国家重点实验室, 南京210009;
    2 南京工业大学化学化工学院, 南京210009
  • 收稿日期:2014-12-23 修回日期:2015-04-14 发布日期:2015-06-05
  • 通讯作者: 费兆阳, 乔旭 E-mail:zhaoyangfei@njtech.edu.cn;qct@njtech.edu.cn
  • 基金资助:

    国家科技支撑计划(2011BAE18B01), 江苏省科技支撑计划(BE2011830), 江苏省高校自然科学基金面上项目(13KJB530006), 国家自然科学基金(21306089)和中国博士后基金(2013M531340)资助

Effects of Rare-Earth Additives on Structures and Performances of CuO-CeO2-SiO2 Catalysts for Recycling Cl2 from HCl Oxidation

XIE Xing-Xing1,2, FEI Zhao-Yang1,2, ZOU Chong1,2, LI Zheng-Zhou1,2, CHEN Xian2, TANG Ji-Hai2, CUI Mi-Fen2, QIAO Xu1,2   

  1. 1 State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 210009, P. R. China;
    2 College of Chemistry and Chemical Engineering, Nanjing Tech University, Nanjing 210009, P. R. China
  • Received:2014-12-23 Revised:2015-04-14 Published:2015-06-05
  • Contact: FEI Zhao-Yang, QIAO Xu E-mail:zhaoyangfei@njtech.edu.cn;qct@njtech.edu.cn
  • Supported by:

    The project was supported by the National Key Technology Research and Development Program of the Ministry of Science and Technology of China (2011BAE18B01), Research and Development Program of Jiangsu Province, China (BE2011830), Higher Education Natural Science Foundation of Jiangsu Province, China (13KJB530006), National Natural Science Foundation of China (21306089) and China Postdoctoral Science Foundation (2013M531340).

摘要:

采用模板法制备了CuO-CeO2-SiO2和稀土掺杂的CuO-Ce0.9M0.1O2-SiO2 (M=La, Pr, Nd)催化剂. 运用X射线衍射(XRD), N2吸附-脱附, 透射电镜(TEM), 拉曼(Raman)光谱, X射线光电子能谱(XPS)和氢气-程序升温还原(H2-TPR)等手段对催化剂的结构进行表征, 并考察稀土掺杂对氯化氢催化氧化制氯气性能的影响. 结果表明, 稀土掺杂进入CeO2晶格中形成良好的固溶体结构, 获得更小的晶粒尺寸和更高的比表面积, 并且显著提高了固溶体的表面氧空位浓度. 稀土掺杂显著影响了催化剂的氯化氢催化氧化活性, 活性顺序为: CuOCe0.9La0.1O2-SiO2>CuO-Ce0.9Nd0.1O2-SiO2>CuO-Ce0.9Pr0.1O2-SiO2>CuO-CeO2-SiO2, 固溶体氧空位浓度的高低与氯化氢氧化活性直接相关. 通过与Ce0.9M0.1O2-SiO2催化剂的结构和性能的对比, 发现氧空位浓度的提高并不能增强在固溶体表面发生的氯化氢氧化反应. 动力学测试显示, 稀土掺杂后, 氧分子的吸附成为反应过程的决速步骤. 但在V(O2):V(HCl)=1 条件下, 更高的氧空位浓度导致了固溶体更低的氯化氢氧化反应速率. 结合机理分析认为, CuO-Ce0.9M0.1O2-SiO2催化剂更高的氧空位浓度增强了固溶体表面的“氧溢流”, 加快了氯化氢氧化的整体反应速率, 这是CuO-Ce0.9M0.1O2-SiO2具备高活性的关键.

关键词: 稀土, 铈铜复合氧化物, 氯化氢, 催化氧化, 氯气, 氧空位

Abstract:

CuO-CeO2-SiO2 and rare-earth-doped CuO-Ce0.9M0.1O2-SiO2 (M=La, Pr, Nd) catalysts for recycling Cl2 from HCl oxidation were prepared by a template method, using activated carbon as a hard template. The catalyst structures were determined using X-ray diffraction (XRD), N2 adsorption-desorption, transmission electron microscopy (TEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and H2 temperatureprogrammed reduction (H2-TPR). The catalytic performances were also investigated. The results showed that La, Pr, and Nd cations were incorporated into the CeO2 lattice and formed nanosized solid solutions; this greatly reduced the catalyst grain sizes, leading to higher surface areas. In addition, the oxygen vacancy concentrations were significantly improved. The changes in the structures and surface properties of the solid solutions significantly affected the HCl catalytic oxidation performances. The order of the activities of various catalysts was CuO-Ce0.9La0.1O2-SiO2>CuO-Ce0.9Nd0.1O2-SiO2>CuO-Ce0.9Pr0.1O2-SiO2>CuO-CeO2-SiO2. The oxygen vacancy concentrations of the solid solutions were strongly related to their catalytic activities. However, the structures and performances of the Ce0.9M0.1O2-SiO2 catalysts showed that an increase in the number of oxygen vacancies resulted in decreased catalytic activities of the solid solutions. Kinetic studies showed that oxygen adsorption could be the rate-determining step for rare-earth-doped catalysts; a higher oxygen vacancy concentration in the solid solution led to a slower reaction rate when the volumetric flow ratio of O2 to HCl was 1. For the CuOCe0.9M0.1O2-SiO2 catalysts, spillover of oxygen species in the solid solution into the highly dispersed CuO interfaces was enhanced, which increased the overall reaction rate and gave high activity.

Key words: Rare earth, CuO-CeO2, HCl, Catalytic oxidation, Chlorine, Oxygen vacancy

MSC2000: 

  • O643