CIESC Journal ›› 2022, Vol. 73 ›› Issue (10): 4438-4447.DOI: 10.11949/0438-1157.20220798

• Catalysis, kinetics and reactors • Previous Articles     Next Articles

Effect of aging process on copper manganese composite catalyst

Kailun FANG(), Shuaishuai CHEN, Jiawei FU, Xin JIANG()   

  1. Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, Zhejiang, China
  • Received:2022-06-10 Revised:2022-09-02 Online:2022-11-02 Published:2022-10-05
  • Contact: Xin JIANG

微反应器研究陈化过程对铜锰催化剂的影响

方凯伦(), 陈帅帅, 付家崴, 蒋新()   

  1. 浙江大学化学工程与生物工程学院,浙江省化工高效制造技术重点实验室,浙江 杭州 310027
  • 通讯作者: 蒋新
  • 作者简介:方凯伦(1997—),男,硕士研究生, 22028158@zju.edu.cn
  • 基金资助:
    国家自然科学基金项目(21676236);国家重点研发计划项目(2017YFC0211802)

Abstract:

Aging process is a significant process in the preparation of Cu-Mn composite oxide catalyst by co-precipitation method, during which the rapid structural change process of precipitates at the very initial stage of formation remain to be explored. In this paper, Cu-Mn catalyst was prepared in a microreactor and aged in an extended section to study the effect of very short aging time on the structure of Cu-Mn precipitate and catalyst. High resolution transmission electron microscope (HRTEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) were used to analyze the species and structural properties of precursors and catalysts obtained at different aging time. The results show that MnCO3 in the precipitate has rapidly completed the transformation from amorphous to crystalline within a few minutes of aging, while the process of Cu2+ entering the crystalline MnCO3 structure takes tens of minutes. The formation of crystalline MnCO3 separates Cu and Mn, while the formation of Cu-Mn composite carbonate gradually improves the dispersion of Cu and Mn. This leads to a regular change in the structural parameters of the catalyst, which makes the catalyst performance first rapidly deteriorate and then slowly improve with aging time.

Key words: microreactor, precipitation, aging process, copper manganese compound oxide, catalyst

摘要:

陈化过程是共沉淀法制备Cu-Mn复合催化剂的关键步骤,沉淀物在形成初期快速的结构变化过程是研究的难点和盲点。采用微反应器制备Cu-Mn催化剂,并利用延长管进行陈化以研究极短陈化时间对Cu-Mn沉淀物及催化剂结构的影响,采用高倍电镜(HRTEM)、X射线衍射(XRD)、热重分析(TG)、拉曼光谱(Raman spectra)、X射线光电子能谱(XPS)对不同陈化时间的沉淀物和催化剂的理化性质进行分析。结果显示,在陈化过程中沉淀物中的MnCO3在数分钟内快速完成了从无定形到结晶态的转变,而Cu2+进入结晶态MnCO3结构的过程需要数十分钟才能完成。结晶态MnCO3的形成使Cu和Mn相互分离,而Cu-Mn复合碳酸盐的形成使得Cu-Mn分散性又逐渐变好。这导致了催化剂的结构参数呈现规律变化,使催化剂性能随陈化时间呈现先迅速变差后缓慢变好的规律。

关键词: 微反应器, 沉淀, 陈化过程, 铜锰复合氧化物, 催化剂

CLC Number: