Abstract:

The Cu/ZnO catalysts were prepared via microchannel reactor and characterized by TEM, XRD and XPS. It was difficult to find the individual CuO or ZnO region in HRTEM picture and XPS analysis indicated that the interaction between CuO and ZnO in microchannel samples was stronger than that in classical co-precipitation samples. The results of methanol synthesis from syngas in liquid manifested that the activity of microchannel catalysts was higher than that of classical co-precipitation catalysts. Comparing the precipitation in microchannel reactor with that of classical co-precipitation, it was found that the strong turbulent and tiny space resulted in a more uniform precipitation of Cu²⁺ and Zn²⁺, intensifying the dispersion and interaction between copper and zinc. In addition, the plug flow in the microchannel reactor made Cu²⁺ and Zn²⁺ undergo more uniform reaction course and form catalysts with more homogeneous structure. The research on tube length indicated that 30 s of the residence time was needed for the Cu-Zn precursors to reach the preliminary structural stability.

Key words: microreactor, mixing, nanomaterials, catalyst microstructure, methanol synthesis

摘要：

采用微通道反应器制备了铜锌催化剂,并利用透射电子显微镜(TEM)、X射线衍射(XRD)和X射线光电子能谱(XPS)等手段进行了表征。HRTEM和XPS分析表明,微反应器样品中 CuO和ZnO之间的相互分散性更好,两者之间的接触更为紧密,液相合成气制甲醇实验表明其活性高于传统共沉淀法催化剂。对比微通道反应器和传统共沉淀法的反应历程表明,微混合器内强烈的湍动和极小的空间,使Cu²⁺、Zn²⁺的沉淀过程更为均匀,增强了铜锌相互分散,强化了铜锌相互作用;同时,Cu²⁺和Zn²⁺在微反应器内经历了更为均匀一致的反应历程,得到的催化剂在结构上更加均匀。通过研究稳定段长度的影响发现,铜锌催化剂前驱体形成后需要经过30 s的停留时间,其结构才能基本稳定。

关键词: 微反应器, 混合, 纳米材料, 催化剂微结构, 甲醇合成