超细钙钛矿型LaCoO3的制备、表征及光催化性能研究

以La₂O₃和Co（NO₃）₂·6H₂O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LaCoO₃。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LaCoO₃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LaCoO₃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LaCoO₃类球形颗粒;900℃时La-Co超细粒子中晶相成分为LaCoO₃和La₂O₃,无定形成分为Co₂O₃,稀土镧影响了钴氧化物的晶化;在超细LaCoO₃催化作用下,10mg/L甲基橙溶液500mL完全降解约需4h。

Preparation,Characteration and Research on Photocatalytic Ability of Ultrafine Perovskite-type Oxide LaCoO_3

Using La₂O₃ and Co（NO₃）₂·6H₂O as raw material,ultrafine perovskite-type oxide LaCoO₃ was prepared by supercritical fluid drying technology and sol-gel method.The prepared materials 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 La₂O₃,and the amorphous component was Co₂O₃,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.