摘要
以La_2O_3和Co(NO_3)_2·6H_2O为主要原料,用溶胶-凝胶法结合超临界流体干燥技术制备了超细钙钛矿型LaCoO_3。采用TG-DTA、XRD、FT-IR和TEM检测手段进行表征;以15W的紫外灯为光源,用甲基橙溶液的光催化降解测试超细LaCoO_3的催化活性。结果显示,250℃时经超临界流体干燥,可获取直径小于10nm的无定形LaCoO_3球形颗粒;850℃热处理后,可制得粒径介于15～35nm之间的钙钛矿型LaCoO_3类球形颗粒;900℃时La-Co超细粒子中晶相成分为LaCoO_3和La_2O_3,无定形成分为Co_2O_3,稀土镧影响了钴氧化物的晶化;在超细LaCoO_3催化作用下,10mg/L甲基橙溶液500mL完全降解约需4h。
Using La203 and Co （NO3）2·6H20 as raw material, ultrafine perovskite-type oxide LaCoO3 was prepared by supercritical fluid drying technology and sol-gel method. The prepared materialsr crystal structure and morphology were characterized by TG-DTA, XRD, FT-IR and TEM. The photocatalytic activity of ultrafine LaCoO3 powders was evaluated by degradation of methyl orange（MO） solution under 15W UV light irradiation. The results show that, at 250℃, La-Co amorphous ultrafine powder with size less than 10nm could be obtained by supercritical fluid drying technology. At 850℃, size of the particles increased to 15-35nm, the nanocrystalline LaCoO3 had a perfect rhombohedral perovskite structure. At 900℃, the crystalline phases of the lanthanum-cobalt composite oxide were LaCoO3 and La203, and the amorphous component was Co203, the presence of lanthanum affected the crystallization of cobalt oxide. The LaCoO3 owned excellent photocatalytic activities and 100% MO solution was decolorized only after 4h.
基金
武汉科技大学校基金(2008XY12)
