以Bi(NO3)3·5H20、Na2WO4·2HzO为原料,NaOH为矿化剂,采用水热法合成BizWO6纳米晶体,并使用X射线衍射仪(XRD)、扫描电子显微镜(sEM)、透射电子显微镜(TEM)对其进行表征,分析了反应时间和温度对晶体生长的影响。利用Johnson—Mehl—Avrami(JMA)方程对不同温度下Bi2W06的水热晶化过程进行动力学模拟分析。结果表明,120~200℃范围内的Avrami指数n随水热反应温度的升高而增长,n介于0.5~1之间。Bi2WO6纳米晶体的水热晶化过程表现为较低温度下的扩散控制生长以及较高温度(T〉160℃)下的相界控制生长。同时,Bi2wO6纳米晶体的生长经历了一个成核、积聚和熟化的过程。
Bismuth Tungstate (Bi2WO6) was prepared by hydrothermal method using Bi(NO3)3 · 5H20 and NaeWO4 · 2H20 as raw materials and NaOH as mineralizer. Samples were characterized by XRD, SEM and TEM. The effects of synthesis time and temperature on the crystal growth process were evaluated. The growth kinetics of bismuth tungstate was evaluated by JMA equation,results showed that Avrami exponent n was loca- ted between 0.5-1 which increased as the reaction temperature increasing from 120 to 200℃. This means that the growth process of nanostructured Bi2WO6 was controlled by diffusion at low temperature region, and con- trolled by interface reaction at high temperature region. gregation and ripening. Then, the growth of crystals experienced nucleation, ag