溶胶-凝胶法制备La_2CuO_4纳米晶生长动力学研究  

Study on Crystal Growth Kinetics of La_2CuO_4 Nano-crystallites Synthesized by Sol-Gel Process

作　　者：李意峰[1] 黄剑锋[1] 曹丽云[1] 吴建鹏[1] 费杰[1] 

机构地区：[1]陕西科技大学教育部轻化工助剂化学与技术重点实验室,西安710021

出　　处：《人工晶体学报》2012年第4期931-935,941,共6页Journal of Synthetic Crystals

基　　金：国家自然科学基金(50942047;51102196);陕西省教育厅自然科学专项基金(2010JK444);陕西省教育厅自然科学专项项目(11JK0820);陕西省自然科学基金(2010JM6001);陕西科技大学研究生创新基金资助项目

摘　　要：以硝酸镧和硝酸铜为起始原料,柠檬酸为络合剂,乙二醇为交联剂,采用溶胶-凝胶法制备了La2CuO4纳米晶。通过XRD和FESEM对La2CuO4粉体进行了测试和表征,研究了不同柠檬酸配比对La2CuO4相组成、显微结构以及晶体生长活化能的影响。结果表明:当柠檬酸与金属阳离子总和(La3++Cu2+)的物质的量比为1∶1,600℃煅烧保温2 h后,可获得单一正交晶型的La2CuO4,颗粒形貌为球状结构,平均尺寸为65 nm;在制备过程中提高柠檬酸的加入量,能够降低La2CuO4晶体的生长活化能,当物质的量比由0.5∶1增加至1∶1时,生长活化能由67.3 kJ/mol降低到50.5 kJ/mol。La2CuO4 nano-crystallites were prepared via a sol-gel process using lanthanum nitrate and cupric nitrate as raw materials, citric acid as complex agent and glycol as cross-linking agent. The influences of citric acid amount on the phase composition, microstructure and growth activation energy of the powders were investigated by XRD and FESEM. The results show that single orthorhombic La2CuO4 nano-crystallites can be obtained after calcined at 600 ℃ for 2 h when the molar ratio of n（ CA）： n（ La3＋ ＋ Cu2＋ ） is 1 ： 1. The particles exhibit spherical microstructure, the average size is about 65 nm. The growth activation energy of La2 CuO4 crystallites decreases when the amount of citric acid increases. With the increase of the molar ratio from 0. 5：1 to 1 ： 1, the growth activation energy decreases from 67.3 k J/ tool to 50.5 kJ/mol.

关 键 词：铜酸镧 溶胶-凝胶法 柠檬酸 生长活化能 

分 类 号：TB34[一般工业技术—材料科学与工程]