摘要：采用燃烧法合成纳米La(OH)₃材料,分别以硝酸镧和柠檬酸为镧源和络合剂,以氨水调节pH值为2～4、柠檬酸与硝酸镧的物质的量比为1～1.2∶1之间,加热凝胶至自蔓延燃烧后并在700～750℃煅烧1～2 h,得到膨松粉末状产物,即La₂O₃纳米晶。利用X射线衍射和透射电镜等测试方法对凝胶热分解过程及最终形成的La₂O₃纳米晶颗粒进行分析和表征。结果表明:用该方法得到的纳米La₂O₃产物的平均粒径在30～100 nm之间可控;纳米La₂O₃在空气中是不稳定的,在自然吸潮情况下和空气中的H2O发生反应生成La(OH)₃,控制湿度即可得到纯La(OH)₃纳米晶。

关键词： 溶胶-凝胶燃烧法;纳米晶;自蔓延燃烧

Abstract： La(OH)₃ nano-particles were synthesized by sol-gel combustion synthesis that citric acid monohydrate was used as the complexing agent and La（NO₃）₃·6H₂O was used as the lanthanum source， the mixture that mole ratio of citric acid and La （NO₃）₃ was 1~1.2∶1 were dissolved in the water， and ammonia solution was added to adjust pH value between 2~4. Then the wet gel was obtained and subsequently heated to cause the self-propagating combustion at 700~750 ℃ for 1~2 h. The fluffy La₂O₃ nano-crystalline was synthesized. The structure and pattern of the as-prepared powders were characterized by XRD and TEM. The results showed that La₂O₃nano-crystalline particles with grain diameter in range from 30 nm to 100 nm were prepared and the size was controlled. La₂O₃ nano-crystalline was unstable to deliquesce with the moisture in the air and finally form La(OH)₃. So pure La(OH)₃ n ano-crystalline was prepared by way of controlling moisture. 

Keywords： sol-gel combustion synthesis； nano-crystalline；self-propaga ting combustion