固相合成In_2O_3纳米晶及动力学的研究

Synthesis of Indium Oxide (In_2O_3) Nanocrystallites and Calcination Kinetics

以InCl3·4H2 O和NaOH为原料 ,利用固相反应合成前驱体 ,再经焙烧合成In2 O3纳米晶。用X射线衍射 (XRD)分析了不同焙烧温度对合成In2 O3晶粒尺寸的影响。研究结果表明 :按Scherrer公式估算合成In2 O3纳米晶的晶粒尺寸在 2 0～ 3 0nm ,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法计算了合成In2 O3纳米晶的活化能分别为 167.0 3和 176.0 6kJ·mol- 1 ,差别不大 ;根据晶粒生长动力学理论计算In2 O3晶粒长大的活化能为 2 .82kJ·mol- 1 ,表明热处理过程In2 O3纳米晶粒的长大主要以界面扩散为主。

Nanocrystalline indium oxide (In 2O 3) was successfully synthesized by heating the precursor obtained by solid-state reaction of InCl 3·4H 2O and NaOH powders. The crystallization kinetic of In 2O 3 nanoparticles was investigated using differential thermal analysis (DTA). The variation of the In 2O 3 nanoparticle size with calcination temperature was discussed by X-ray diffraction (XRD) technique. The mechanism for the nanocrystallite growth was primarily investigated. The results indicate that the synthesized In 2O 3 has a crystalline structure with a crystal size of 20～ 30 nm calculated by Scherrer equation, varying with increasing the calcination temperature. The apparent activation energy of In 2O 3 nanocrystallite formation after heating the precursor was analyzed using Kissinger and Ozawa methods. The values are 167.03 and 176.06 kJ·mol -1, respectively. The activation energy for the crystallite growth is calculated to be 2.82 kJ·mol -1 according to dynamic theory of nanocrystallite growth. It can be considered that the crystallite grows primarily by means of an interfacial reaction during the thermal treatment.