摘要
采用微波辅助柠檬酸络合法制备一系列不同铈锆比的铈锆固溶体,考察不同含量锆的掺杂对制备固溶体结构特性以及催化分解甲硫醇性能的影响。通过XRD,BET,Raman,XPS,H_2-TPR,CH_3SH-TPD等手段对其结构物化性能进行表征。表征结果显示:该制备方法成功合成铈锆固溶体且均保留立方萤石结构;锆的引入会导致合成固溶体的晶粒变小、晶格收缩,且晶格参数a随着锆引入量的增加而降低;同时,锆的添加仅仅导致物种缺陷的形成而不会产生更多的氧空位。此外,不同铈锆比固溶体催化分解甲硫醇活性实验结果表明:Ce_(0.75)Zr_(0.25)O_2氧复合物表现出最好的催化活性,之后随着锆的添加其催化性能呈现下降趋势。根据BET,XPS及H_2-TPR表征结果:在表面晶格氧相对含量相近的情况下,Ce_(0.75)Zr_(0.25)O_2因具有最大比表面积、最好的还原性能而表现出最佳的甲硫醇催化活性。最后,考察了Ce_(0.75)Zr_(0.25)O_2催化分解甲硫醇的产物分布情况,结合CH_3SH-TPD表征结果表明:铈锆固溶体催化分解甲硫醇的反应中,二甲基硫醚为中间产物且仅在低温区产生。
A series of cerium zirconium solid solutions with different Ce/Zr ratios were rapidly synthesized by a citric acid complexation method with microwave-assisted. The influence of introduction of different content Zr ions on the structural properties of the catalysts and the catalytic performance for decomposing CH3SH was investigated.Structural physical and chemical properties of cerium zirconium solid solutions were characterized by XRD,BET,Raman,XPS,H2-TPR,CH3SH-TPD etc. Characterization results showed that the preparation method successfully synthesizes cerium zirconium solid solutions which all retain cubic fluorite structure. The introduction of zirconium leads to smaller grain size and lattice shrinkage of the synthesized solid solution,and the lattice parameter a decreases with the increase of doped zirconium. At the same time,addition of zirconium only results in the formation of species defects without producing more oxygen vacancies. Furthermore,the results of catalytic activity over solid solution with different cerium zirconium ratio showed that Ce（0.75）Zr（0.25）O2 exhibits the best catalytic activity,and the catalytic performance decreases with the introduction of zirconium. According to BET,XPS and H2-TPR characterization,under the condition of close surface lattice oxygen content,Ce（0.75）Zr（0.25）O2 has the best specific surface area and the best reduction performance,which shows the best catalytic activity for decomposing methyl mercaptan. Finally,the product distribution of methyl mercaptan catalyzed by Ce（0.75）Zr（0.25）O2 was studied. Combined with CH3SHTPD,CH3SCH3 is intermediate and can be only produced in low temperature region.
作者
陈定凯
何德东
陆继长
刘峰
刘江平
余杰
韩彩芸
高晓亚
何素芳
罗永明
Chen Dingkai;He Dedong;Lu Jichang;Liu Feng;Liu Jiangping;Yu jie;(Han Caiyun;Gao Xiaoya;He Sufang;Luo Yongming;Faculty of Environmental Science and Engineering,Kunming University of Science and Technology)
出处
《中国稀土学报》
CAS
CSCD
北大核心
2018年第2期172-182,共11页
Journal of the Chinese Society of Rare Earths
基金
国家自然科学基金项目(U21667016
1402233
21267011和21367015)
云南省省级基金项目(KKSY201422060)
云南省教育厅面上基金项目(KKJA201422018)资助
关键词
铈锆固溶体
甲硫醇
催化分解
铈锆比
还原性
二甲基硫醚
cerium zirconium solid solutions
CH3 SH
catalytic decomposition
Ce/Zr ratios
reducibility
CH3 SCH3
