(暨南大学 化学系，广州 510632)
摘 要: 采用4种方法制备LaFeO3催化剂，探讨制备方法对LaFeO3催化剂结构和性能的影响。用XRD、UV-Vis DRS、PL和SEM等手段对样品进行表征。以罗丹明B为目标降解物，考察催化剂的可见光光催化活性。研究结果表明：这4种方法均能制备单一的钙钛矿型LaFeO3催化剂，其中，共沉淀法制备的催化剂具有最大的晶粒尺寸，最小的比表面积，仅为0.4 m2/g，显示出最强的光催化活性；在可见光照射下反应140 min，罗丹明B的脱色率达到53.6%。柠檬酸络合法制备的催化剂的比表面积最大，为8.1 m2/g，但其脱色率仅为9.0%。由此可推断，小的颗粒和高的比表面积并不是总有利于催化剂的光催化活性，大的晶粒和规整的表面形貌等对催化活性也具有决定性的影响。
关键字: LaFeO3；可见光；罗丹明B；共沉淀法
LaFeO3 under visible light irradiation
（Department of Chemistry, Jinan University, Guangzhou 510632, China）
Abstract:LaFeO3 catalysts were prepared by four kinds of methods to explore the effects of preparation methods on structure and performance of LaFeO3 catalyst. The samples were characterized by X-ray diffraction, UV-visible diffuse reflectance spectrum, photoluminescence spectrum, scanning electron microscopy and N2-adsorption. The photocatalytic activities of different catalysts were investigated by utilizing rhodamine B as degradation agent under visible light irradiation. The results show that the sample prepared by coprecipitation method exhibits the highest activity and has the largest crystallite size, and after reaction for 140 min, 53.6% of rhodamine B is decolored; while for catalyst prepared by the citric acid complexation, the decoloration ratio is only 9.0%, though the latter has a higher surface area and smaller crystallite size than the former. The results suggest that smaller crystallite size and higher surface area are not always favorable to photo catalytic activity of a catalyst, other factors, such as large crystallite size and regular morphology, also play a crucial role.
Key words: LaFeO3; visible light; rhodamine B; coprecipitation method
