摘要
以Co(NO3)2·6H2O和NH4HCO3为原料,利用固相反应合成无定形前驱体,再经焙烧合成Co3O4纳米晶。用X射线衍射(XRD)分析了不同焙烧温度对合成Co3O4晶粒尺寸的影响。研究结果表明:按Scherrer公式估算合成Co3O4纳米晶的晶粒尺寸在10～40nm,焙烧温度越高,晶粒尺寸越大;根据前驱体不同升温速率下的差热(DTA)曲线,用Kissinger和Ozawa法计算合成Co3O4纳米晶的活化能分别为132.77kJmol和141.17kJmol,差别不大;根据晶粒生长动力学理论计算Co3O4晶粒长大的活化能为15.44kJmol,表明热处理过程Co3O4纳米晶粒的长大主要以界面扩散为主。
Nanocrystalline cobalt oxide (Co3O4) was successfully synthesized after thermal treatment of the precursor obtained by solid-state reaction of Co(NO3)2 · 6H2O and NH4HCO3. The crystallization kinetics of Co3O4 nanoparticles was investigated by differential thermal analysis (DTA). The variation of the Co3O4 nanoparticle size with calcination temperature was investigated using X-ray diffraction (XRD) technique. The mechanism for the nanocrystallite growth was primarily investigated. The results indicate that the prepared Co3O4 has a nanocrystalline structure with average crystal size of 10-40 nm, which varies with the calcination temperature. The apparent activation energies of Co3O4 nanocrystallite formation after heating the precursor are analyzed using Kissinger and Ozawa methods, the values are 132.77 kJ/mol and 141.17 kJ/mol, respectively. The activation energy for the nanocrystallite growth is calculated to be 15.44 kJ/mol according to kinetics theory of nanocrystallite growth, indicating that Co3O4 nanocrystallite grows primarily by means of an interfacial reaction during the thermal treatment.
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2005年第4期1-4,共4页
Transactions of Materials and Heat Treatment
基金
国家自然科学基金资助项目(50304014)
湖南省科技攻关计划资助项目(03GKY3038)
中南大学研究生教育创新工程资助项目(030702)
长沙大学科学技术研究基金资助项目(SF030302)
关键词
四氧化三钴(Co3O4)
纳米晶
固相合成
动力学
活化能
Activation energy
Calcination
Catalyst supports
Cobalt compounds
Crystal growth
Differential thermal analysis
Heat treatment
Nanostructured materials
Oxides
X ray diffraction analysis
