溶胶-凝胶法制备La2CuO4纳米晶生长动力学研究

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2h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.

Study on Crystal Growth Kinetics of La2CuO4 Nano-crystallites Synthesized by Sol-Gel Process

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 La2CuO4 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 kJ/mol to 50.5 kJ/mol.