(暨南大學 化學系，廣州 510632)
摘 要: 采用4種方法制備LaFeO3催化劑，探討制備方法對LaFeO3催化劑結構和性能的影響。用XRD、UV-Vis DRS、PL和SEM等手段對樣品進行表征。以羅丹明B為目標降解物，考察催化劑的可見光光催化活性。研究結果表明：這4種方法均能制備單一的鈣鈦礦型LaFeO3催化劑，其中，共沉淀法制備的催化劑具有最大的晶粒尺寸，最小的比表面積，僅為0.4 m2/g，顯示出最強的光催化活性；在可見光照射下反應140 min，羅丹明B的脫色率達到53.6%。檸檬酸絡合法制備的催化劑的比表面積最大，為8.1 m2/g，但其脫色率僅為9.0%。由此可推斷，小的顆粒和高的比表面積并不是總有利于催化劑的光催化活性，大的晶粒和規(guī)整的表面形貌等對催化活性也具有決定性的影響。
關鍵字: LaFeO3；可見光；羅丹明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
