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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
  • ISSN号:1000-6818
  • 期刊名称:《物理化学学报》
  • 时间:0
  • 分类:O643[理学—物理化学;理学—化学]
  • 作者机构:[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
  • 相关基金: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); 中国博士后基金(2013M531340)资助
中文摘要:

采用模板法制备了Cu O-Ce O2-Si O2和稀土掺杂的Cu O-Ce0.9M0.1O2-Si O2(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Ce O2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:Cu OCe0.9La0.1O2-Si O2〉Cu O-Ce0.9Nd0.1O2-Si O2〉Cu O-Ce0.9Pr0.1O2-Si O2〉Cu O-Ce O2-Si O2,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-Si O2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,Cu O-Ce0.9M0.1O2-Si O2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Cu O-Ce0.9M0.1O2-Si O2具备高活性的关键.

英文摘要:

CuO-CeO2-SiO2 and rare-earth-doped CuO-Ce0.9M0.1O2-SiO2 (M=La, Pr, Nd) catalysts for recycling Cl2 from HCI 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 temperature- programmed 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 HCI catalytic oxidation performances. The order of the activities of various catalysts was CuO-Ce0.9La0.1O2-SiO2〉CuO-CeogNd0.1O2-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 Ce0.0M0.1O2-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 02 to HCI was 1. For the CuO- Ce0.9M0.1O2-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.

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期刊信息
  • 《物理化学学报》
  • 中国科技核心期刊
  • 主管单位:中国科学技术协会
  • 主办单位:北京大学化学与分子工程学院承办
  • 主编:刘忠范
  • 地址:北京大学化学楼
  • 邮编:100871
  • 邮箱:whxb@pku.edu.cn
  • 电话:010-62751724
  • 国际标准刊号:ISSN:1000-6818
  • 国内统一刊号:ISSN:11-1892/O6
  • 邮发代号:82-163
  • 获奖情况:
  • 中文核心期刊
  • 国内外数据库收录:
  • 俄罗斯文摘杂志,美国化学文摘(网络版),荷兰文摘与引文数据库,美国科学引文索引(扩展库),英国科学文摘数据库,日本日本科学技术振兴机构数据库,中国中国科技核心期刊,中国北大核心期刊(2004版),中国北大核心期刊(2008版),中国北大核心期刊(2011版),中国北大核心期刊(2014版),英国英国皇家化学学会文摘,中国北大核心期刊(2000版)
  • 被引量:24781