纳米LaCoO_3的声化学制备及结构和催化燃烧活性

Sonochemical Preparation, Structure and Catalytic Combustion Activity of Nanosized LaCoO_3

使用超声共沉淀法制备了LaCoO3复合氧化物纳米催化剂,研究了共沉淀过程中超声波对LaCoO3结构性质和催化活性的影响.X 射线衍射分析(XRD)、表面吸附(BET)、透射电子显微镜(TEM)、X 射线光电子能谱(XPS)和活性评价等表征的结果表明,在共沉淀过程中施加超声波辐照,可以使LaCoO3复合氧化物的生成温度降低,粒径减少,比表面积增加,表面B位元素含量增加,表面晶格氧空位增加,表面吸附氧种增加,使LaCoO3催化剂的表面氧种活化,使LaCoO3催化剂的催化活性增加.

The nanosized LaCoO3 was prepared by co-precipitation under ultrasonic radiation. Using X-ray powder diffraction (XRD), transmission electron micrograph (TEM), scanning electron micrograph (SEM), surface adsorption (EBT), X-ray photoelectron spectroscopy (XPS) and evaluation of catalytic activity, the effects of ultrasound on the structured properties and catalytic activity were studied. The results of XRD show the ultrasound can decrease the formation temperature of LaCoO3. The results of TEM show the ultrasound can decrease particle size. The average particle size of LaCoO3 is 12 nm. The specific surface area of LaCoO3 is 14.84 m2/g by BET. The Co3+/La3+ on surface are 0.92 (ultrasound) and 0.82 (without ultrasound), the Oads/Olat on surface are 1.30 (ultrasound) and 1.18 (without) by XPS. It shows the ultrasound can increase surface content of Co, and increase number of surface crystal oxygen vacancies. The result of evaluation of catalytic activity shows ultrasound can increase catalytic activity of LaCoO3 for NO decompostition and CO oxidation.