Influence of mixing inside microreactor on microstructural evolution of Cu-ZnO catalyst

doi:10.11949/j.issn.0438-1157.20170976

Abstract

Abstract:

The influence of mixing inside the microreactor on the microstructural evolution of Cu-ZnO catalyst was investigated by regulating the flow rate. Mixing efficiency in the microreactor was measured by Villermaux-Dushman reaction system under different flow rates, and the structures of precursor and oxide were characterized by X-ray powder diffraction (XRD), energy dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). The results showed that with increase of the mixing intensity, the distribution of Cu²⁺ and Zn²⁺ in precursor becomes more uniform, the fraction of aurichalcite decreases and Zn content in zincian malachite rises. The difference in the precursors acts on the oxides, leading to a more uniform Cu-Zn distribution, a better dispersion between CuO and ZnO, and the decrease of CuO size. Above study reveals, it is by the Cu-Zn distribution that the changes of mixing during the precipitation affects the subsequent product and results in the difference in Cu-ZnO catalyst microstructure.

Key words: microreactor, mixing, nanostructure, co-precipitation, flow rate, Cu-Zn distribution

摘要：

通过对微反应器中流速的调控，研究了混合过程对Cu-ZnO催化剂微结构形成过程的影响。采用Villermaux-Dushman反应体系测量了不同流速下反应器中的混合状况，采用X射线衍射（XRD）、高倍电镜线扫（EDS）、X射线光电子能谱（XPS）分析了对应流速下制备得到的前体和氧化物的结构。结果显示，混合强度增加，前体中的Cu²⁺、Zn²⁺分布更为均匀，绿铜锌矿的比例减小，锌孔雀石中的Zn含量提高；进而导致其热分解形成的氧化物中Cu-Zn分布也更为均匀，CuO-ZnO界面增加，CuO晶粒粒径减小。研究表明，沉淀反应时混合条件的改变，导致后续系列中间产物中Cu-Zn分布的差异，通过这一路径，混合对反应的影响最终作用于催化剂结构。

关键词: 微反应器, 混合, 纳米结构, 共沉淀法, 流速, Cu-Zn分布

CLC Number:

TQ426.6

LING Chen, JIANG Xin, WANG Zhiyong, QIN Xiangfei, LU Jiangang. Influence of mixing inside microreactor on microstructural evolution of Cu-ZnO catalyst[J]. CIESC Journal, 2018, 69(2): 718-724.

凌晨, 蒋新, 汪志勇, 秦湘飞, 卢建刚. 微反应器中的混合对Cu-ZnO催化剂微结构形成过程的影响[J]. 化工学报, 2018, 69(2): 718-724.

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