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.
出处
《中南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
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)
关键词
纳米CEO2
热分解动力学
化学沉淀法
CeO2 nanocrystalline
thermal decomposition kinetics
chemical precipitation method
