超声共沉淀法制备纳米结构LaNiO_3及其性质

Properties and Sonochemical Preparation of Nanostructured LaNiO_3

使用超声共沉淀法制备了LaNiO3复合氧化物纳米催化剂,研究了共沉淀过程中超声波对LaNiO3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）、程序升温还原（TPR）和活性评价等表征.结果表明,在共沉淀过程中施加超声波辐照,可以使LaNiO3复合氧化物的粒径减小,比表面积增加,表面晶格氧空位增加,表面吸附氧种增加,使LaNiO3催化剂的表面氧种活化,表面氧与体相晶格氧的比例增加,使LaNiO3催化剂的催化活性增加.探讨了超声波作用的机理.

Nanostuctured LaNiO3 was prepared by coprecipitation under ultrasonic radiation. Using XRD, TEM, BET, XPS, TPR and evaluation of catalytic activity, the effects of ultrasound on the structured properties and catalytic activity of LaNiOs were studied. The result of TEM showed that the ultrasound could cause decrease of particle size. The average particle size of LaNiO3 prepared by sonochemistry is 20 nm(see Fig. 2b). The specific surface area of LaNiOs is 11.27 m2.g^1 by BET. The Oads/Oads on surface are 1. 25(ultrasound) and 1.01 (without ultrasound) by XPS (see Fig. 4). It showed that ultrasound could lead to increase surface content oxide and increase number of surface crystal oxygen vacancies. The result of TPR showed LaNiO3 prepared by sonochemistry has lower reduction temperature and bigger ratio of surface oxygen to crystal oxygen (see Table 1). The result of evaluation of catalytic activity showed that ultrasound could increase that catalytic activity of LaNiO3 for NO decomposition (see Fig. 6). The role played by of ultrasound was discussed.