溶胶凝胶自燃烧法合成LaFeO_3纳米晶

Synthesis of Nanocrystalline LaFe0_3 by Sol-gel Auto-combustion Method

将溶胶凝胶法和低温燃烧法相结合，开发了一种溶胶凝胶自燃烧法合成纳米晶技术，并 用此技术合成了ＬａＦｅＯ３。纳米晶。利用ＸＲＤ、ＴＥＭ和ＢＥＴ对合成的纳米晶进行了结构、形貌、大小和 比表面积的测量和表征。并借助于ＴＧ—ＤＴＡ研究了干凝胶的自蔓延特性和析晶过程。结果表明，由 硝酸盐和柠檬酸盐形成的干凝胶，具有自蔓延燃烧的特性，自燃烧的本质是在硝酸氨的参与下，硝酸 根作氧化剂，柠檬酸中的含碳基团为还原剂（燃料），它们之间发生氧化还原反应。干凝胶自燃烧后， 直接在室温下形成 ４０～６０ ｎｍ具有钙钛矿结构的纯相晶态的 ＬａＦｅＯ３纳米晶。

Nanocrystalline LaFeO3 was prepared by a novel sol-gel auto-combustion method. The structure, morphology, size and specific surface were characterized and measured by XRD, TEM and BET techniques, and the property of dried gels' auto-combustion and crystallization were studied by TG-DTA. The results indicate the gels, made from the aqueous solutions of citric acid and nitrate, take on the characterization of auto-combustion when being ignited at any point of dried gels. Nanocrystalline LaFeO3 is directly formed after combustion with particle size of 40-60nm. The as-synthesized powders were single and crys-tal LaFeO3 phase.