化工进展 ›› 2021, Vol. 40 ›› Issue (2): 881-889.DOI: 10.16085/j.issn.1000-6613.2020-0572

• 工业催化 • 上一篇    下一篇

基于CuAl-LDH载体制备高分散Cu/ZnO/Al2O3催化剂及其催化性能

张华成(), 孔令奇, 李忠, 郑华艳()   

  1. 太原理工大学煤科学与技术教育部和山西省重点实验室,山西 太原 030024
  • 收稿日期:2020-04-13 修回日期:2020-05-21 出版日期:2021-02-05 发布日期:2021-02-09
  • 通讯作者: 郑华艳
  • 作者简介:张华成(1992—),男,硕士研究生,研究方向为一碳化学。E-mail:1310600159@qq.com
  • 基金资助:
    山西省应用基础研究计划(201901D111118);国家自然科学基金(U1510203)

Preparation of highly dispersed Cu/ZnO/Al2O3 catalyst based on CuAl-LDH carrier and its catalytic performance

Huacheng ZHANG(), Lingqi KONG, Zhong LI, Huayan ZHENG()   

  1. Key Laboratory of Coal Science and Technology of Ministry of Education and Shanxi Province, Taiyuan University of Technology, Taiyuan 030024, Shanxi, China
  • Received:2020-04-13 Revised:2020-05-21 Online:2021-02-05 Published:2021-02-09
  • Contact: Huayan ZHENG

摘要:

通过沉积沉淀法制备了以层状CuAl-LDH为载体负载不同Cu/Zn比例的前体,经热处理得到CuZnAl-LDO复合催化剂,应用于合成气制甲醇反应。采用电感耦合等离子体发射光谱(ICP)、X射线衍射(XRD)、H2程序升温还原(H2-TPR)、N2O化学吸附、N2吸脱附、透射电镜(TEM)和X射线光电子能谱技术(XPS)等手段对前体及催化剂进行表征,考察了水滑石的限域效应和金属-载体相互作用对催化剂活性及稳定性的影响。结果发现:由于水滑石特殊的层状结构,具有较大比表面积和丰富孔道结构,促进了Cu物种的分散,有利于催化剂表面对CO和H2的吸附,增加了Cu、Zn之间的相互作用,提高了催化剂的催化活性。在水滑石前体拓扑转变过程中,层板羟基和水脱除后形成的粗糙表面对所负载的Cu活性物种起到限域作用,抑制了Cu的迁移和团聚。其中,Cu0.6Zn0.3Al0.1-LDO催化剂催化合成甲醇的时空收率达到883mg/(g?h),且反应120h后仅下降2.8%,较共沉淀制备催化剂失活速率降低了81%,表现出较好的催化活性及稳定性。

关键词: 铜锌铝催化剂, 水滑石, 限域效应, 合成气, 甲醇

Abstract:

The CuZnAl-LDO composite catalysts with different Cu/Zn ratios were prepared by using the deposition-precipitation method and layered CuAl-LDH as the carrier. The ICP, XRD, H2-TPR, N2O-chemisorption, N2 sorption isotherms, TEM and XPS analyses were performed to characterize the textural properties of the precursors and the catalysts. The results showed that the special layered structure of hydrotalcite with large specific surface area and abundant pore structure promoted the dispersion of Cu species and increased the interaction between Cu and ZnO, which were conducive to the adsorption of CO and H2 on the catalyst surface and hence increased the catalytic activity. In the topological transformation of hydrotalcite precursor, the rough surface formed by the removal of lamellar hydroxyl and water confined the loaded Cu active species and inhibited their the migration and agglomeration. The space-time yield of methanol for Cu0.6Zn0.3Al0.1-LDO reached 883mg/g/h, and decreased by just 2.8% after 120h. The deactivation rate of the present catalyst decreased by 81% as that of the catalyst prepared by the co-precipitation method, suggesting its excellent catalytic activity and stability.

Key words: CuZnAl catalysts, layered double hydroxides, confined effect, syngas, methanol

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