沉淀法合成的纳米CeO_2前驱体的热分解动力学  

Thermal decomposition kinetics of precursor of CeO_2 nanocrystalline prepared by precipitation method

作　　者：宋晓岚[1] 何希[1] 杨海平[1] 徐大余[1] 江楠[1] 邱冠周[1] 

机构地区：[1]中南大学资源加工与生物工程学院,湖南长沙410083

出　　处：《中南大学学报（自然科学版）》2007年第3期428-432,共5页Journal of Central South University:Science and Technology

基　　金：科技部国际科技合作项目(2005DFBA028);国家自然科学基金资助项目(59925412)

摘　　要：以Ce(NO3)3.6H2O为铈源,(NH4)2 CO3.H2O为沉淀剂,加入少量PEG4000作为分散剂,采用化学沉淀法并经水洗、超声波醇洗,70℃干燥后得到CeO2的前驱体Ce2(CO3)3.H2 O。对Ce2(CO3)3.H2 O样品运用差示/热重分析(DSC/TG)和X射线衍射(XRD)方法进行其热分解过程研究,并通过多重速率扫描法记录样品在不同升温速率下的DSC/TG曲线,采用Kissinger-Akahira-Sunose(KAS)法和Coats-Redfern法进一步研究Ce2(CO3)3.H2 O的热分解动力学。研究结果表明:Ce2(CO3)3.H2 O热分解反应过程分2步进行,主要反应阶段的反应动力学参数是:反应活化能为105.51 kJ/mol,反应级数为2,频率因子为3.61;由此推断出可能的Ce2(CO3)3.H2 O热分解机理函数为Anti-Jander方程,受三维扩散机制控制。With Ce（NO3）3·6H2O and （NH4）2CO3·H2O as raw materials, the precursor Ce2（CO3）3·H2O of CeO2 nanocrystalline was prepared by chemical precipitation method using a little amount of PEG4000 as surfactant, The technique of DSC/TG and XRD were used to study the process of thermal decomposition. In particular, the differential thermal analysis curves were measured at different temperature raising-rate in air atmosphere for decomposition of the precursor of CeO2 nanocrystalline by thermal analysis apparatus. The kinetics process was studied with the method of Kissinger-Akahira-Sunose（KAS） and Coats-Redfern. The results show that the decomposition of Ce2（COa）3·H2O consists of two steps. The active energy of the main step is 105.51 kJ/mol, the reaction order is 2, and the frequency factor is 3.61. The possible conversion functions for the decomposition of the precursor of CeO2 nanocrystalline is Anti-Jander equation and the mechanism of reaction is three-dimensional diffusion.

关 键 词：纳米CEO2 热分解动力学 化学沉淀法 

分 类 号：TB383[一般工业技术—材料科学与工程]