微反应器研究陈化过程对铜锰催化剂的影响  

Effect of aging process on copper manganese composite catalyst

作　　者：方凯伦 陈帅帅[1] 付家崴 蒋新[1] FANG Kailun;CHEN Shuaishuai;FU Jiawei;JIANG Xin(Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology,College of Chemical and Biological Engineering,Zhejiang University,Hangzhou 310027,Zhejiang,China)

机构地区：[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

出　　处：《化工学报》2022年第10期4438-4447,共10页CIESC Journal

基　　金：国家自然科学基金项目(21676236);国家重点研发计划项目(2017YFC0211802)。

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MnCO_(3)在数分钟内快速完成了从无定形到结晶态的转变,而Cu^(2+)进入结晶态MnCO_(3)结构的过程需要数十分钟才能完成。结晶态MnCO_(3)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。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 MnCO_(3) in the precipitate has rapidly completed the transformation from amorphous to crystalline within a few minutes of aging,while the process of Cu^(2+) entering the crystalline MnCO_(3) structure takes tens of minutes.The formation of crystalline MnCO_(3) 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.

关 键 词：微反应器 沉淀 陈化过程 铜锰复合氧化物 催化剂 

分 类 号：TQ426.6[化学工程]