催化学报

催化学报 ›› 2016, Vol. 37 ›› Issue (3): 378-388.DOI: 10.1016/S1872-2067(15)61032-4

• 论文 • 上一篇    下一篇

H型镁碱沸石负载对Cu-ZnO-Al2O3催化剂上CO加氢生成烃类的影响

J. H. Floresa, M. E. H. Maia da Costab, M. I. Pais da Silvaa   

  1. a 里约热内卢天主教大学生物化学系, 里约热内卢22453-900, 巴西;
    b 里约热内卢天主教大学物理系, 里约热内卢22453-900, 巴西
  • 收稿日期:2015-10-29 修回日期:2015-12-09 出版日期:2016-02-29 发布日期:2016-02-29
  • 通讯作者: M. I. Pais da Silva

Effect of Cu-ZnO-Al2O3 supported on H-ferrierite on hydrocarbons formation from CO hydrogenation

J. H. Floresa, M. E. H. Maia da Costab, M. I. Pais da Silvaa   

  1. a Departamento de Química, Pontifícia Universidade Católica, 22453-900, Rio de Janeiro, RJ, Brazil;
    b Departamento de Física, Pontifícia Universidade Católica, 22453-900, Rio de Janeiro, RJ, Brazil
  • Received:2015-10-29 Revised:2015-12-09 Online:2016-02-29 Published:2016-02-29
  • Contact: M. I. Pais da Silva
  • Supported by:

    This work was supported by CAPES.

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摘要：

采用三种不同方法制备了Cu-Zn-Al基甲醇催化剂, 然后在水相悬浮液中与H型镁碱沸石混合分散, 以制得负载型甲醇催化剂. 运用X射线衍射、N2吸附-脱附、透射电镜、程序升温还原、NH3程序升温脱附、H2程序升温脱附和X射线光电子能谱对催化剂进行了表征. 考察了催化剂催化CO加氢反应生成二甲醚和烃类的性能. 该催化剂是在低和高过饱和度条件下采用共沉淀法和均匀沉淀法制得的. 制备方法对前驱体的结构特性 (如纯度、结晶度和催化剂颗粒粒径分布)有显著影响. 低过饱和度的沉淀条件有利于Cu物种的高度分散, 增加了催化剂中金属的比表面积, 所得催化剂粒径分布均匀. 这些效应进而会影响分子筛的性质, 导致其微孔孔体积较小, 分子筛酸性位被堵塞. 通过Cu比表面积和CO转化速率之间的关联可考察甲醇催化剂的性能.

关键词: 甲醇合成催化剂, 低和高过饱和度下沉淀, 合成气, 镁碱沸石, 烃类, 二甲醚

Abstract:

Methanol synthesis catalysts based on Cu, Zn and Al were prepared by three methods and subsequently mixed with H-ferrierite zeolite in an aqueous suspension to disperse the catalysts over the support. These materials were characterized by X-ray diffraction, N2 adsorption, transmission electron microscopy, temperature programmed reduction, NH3 and H2 temperature-programmed desorption, and X-ray photoelectron spectroscopy. They were also applied to the CO hydrogenation reaction to produce dimethyl ether and hydrocarbons. The catalysts were prepared by coprecipitation under low and high supersaturation conditions and by a homogeneous precipitation method. The preparation technique was found to affect the precursor structural characteristics, such as purity and crystallinity, as well as the particle size distribution of the resulting catalyst. Low supersaturation conditions favored high dispersion of the Cu species, increasing the methanol synthesis catalyst's metallic surface area and resulting in a homogeneous particle size distribution. These effects in turn were found to modify the zeolite properties, promoting both a low micropore volume and blockage of the zeolite acid sites. The effect of the methanol synthesis catalyst on the reaction was verified by the correlation between the Cu surface area and the CO conversion rate.

Key words: Methanol synthesis catalyst, Low supersaturation precipitation, High supersaturation precipitation, Syngas, Hydrotalcite, Hydrocarbon, Dimethyl ether