材料期刊网

以硝酸锆和硝酸稀土为原料,甘氨酸水溶液和无机盐作为溶剂和分散剂,通过盐助甘氨酸自蔓延燃烧法(Salt-assistant glycine combustion method,SGCM)得到的前驱体在700℃以下热处理,合成了系列 Ln2 Zr2 O7纳米晶。探讨了最佳反应条件,研究了反应历程,讨论了惰性盐助剂在反应过程中的作用,比较了使用盐助剂与否对产物的分散性差别等。结果表明,在盐助甘氨酸自蔓延燃烧法合成中通过改变 n Gly/n NO 3-的比率,调节盐助剂量 n Salt/n M来对反应温度进行控制,得到的产物的结晶度高,团聚少,粒子更均匀,尺寸在20 nm 左右,晶体形貌完整,光催化活性强；Ln2 Zr2 O7的光催化主要源于稀土离子；稀土离子的光催化与4f 电子结构的相关性,和稀土离子磁矩与4f 电子结构的相关性是同源的。

Ln2 Zr2 O7 nanocrystal series were prepared according the following procedure:first,the precursors were synthesized thrugh salt-assistant gylcine combustion method (SGCM)using zirconium nitrate and rare earth ni-trates as raw materials while glycine aqueous solution and inorganic salt as solvent and dispersant,respectively,fol-lowed by thermal treatment of the responding precursors under 700 ℃.The reaction conditions were optimized and the reaction process was investigated.Furthermore,the role of inert salt assistant in the reaction was discussed while the dispersion difference of the products synthesized with and without salt assistant was compared.The results demon-strated that the products about 20 nm in size with high crystallinity,less agglomeration and improved particles homo-geneity as well as complete crystal morphology and enhanced photocatalytic activity could be obtained through altering the ratio of n Gly/n NO- and adjusting the dose of salt assistant to control the reaction temperature during salt-assistant glycine combustion synthesis procedure.The photocatalytic activity of Ln2 Zr2 O7 mainly came from rare earth ions while the photocatalytic activity of rare earth ions had a correlation to the structure of 4f electronic shell and the corre-lation was homogenous with that between magnetic torque and 4f electronic shell of rare earth ions.