不同溶剂对溶胶-凝胶法制备La2CuO4晶体的影响

以硝酸镧和硝酸铜为起始原料,柠檬酸为络合剂,分别以蒸馏水、乙醇、乙二醇和乙二醇甲醚为溶剂,采用溶胶-凝胶法制备了La2CuO4纳米晶。通过X射线衍射(XRD)、红外光谱(IR)、扫描电子显微镜(SEM)和紫外-可见-近红外光谱(UV-Vis-NIR)等方法对La2CuO4粉体进行了测试和表征;研究了不同溶剂对La2CuO4相组成、官能团、显微结构以及光学性能的影响。结果表明,以蒸馏水、乙醇和乙二醇为溶剂,600℃煅烧保温2h,均能获得单一La2CuO4物相,而以乙二醇甲醚为溶剂时,产物含有杂质相,所得粉体的形貌依次为网片状、蜂窝状、网状和块状。根据UV-Vis-NIR分析,所得La2CuO4的光学带隙分别为1.37、1.30、1.33和1.32eV。

Effects of different solvents on preparation of La2CuO4 crystallites synthesized by sol-gel process

La2CuO4 crystallites were prepared via a sol-gel process using lanthanum nitrate and cupric nitrate as raw materials,citric acid as complexing agent,while distilled water,ethanol,ethylene glycol and ethylene glycol monomethyl ether as solvent,respectively.The influences of different solvents on phase composition,functional group,microstructure and optical property of as-prepared La2CuO4 crystallites were investigated by X-ray diffraction,infrared spectrum,scanning electron microscope and UV-Vis-Nir spectrophotometer.Results show that single La2CuO4 crystallites can be obtained after calcining at 600℃ for 2h,except ethylene glycol monomethyl ether as solvent.The morphologies of the samples are nets flake,honeycomb,mesh and blocks when the solvent is distilled water,ethanol,ethylene glycol and ethylene glycol monomethyl ether,respectively.According to UV-Vis-Nir spectral analysis,the corresponding optical band gap of La2CuO4 crystallites was about 1.37,1.30,1.33 and 1.32eV.