纳米磁性Ag_(2)S/CoFe_(1.95)Y_(0.05)O_(4)的制备及其光催化性能研究

Preparation of nano magnetic Ag_(2)S/CoFe_(1.95)Y_(0.05)O_(4)and its photocatalytic activity

采用水热合成法制备了纳米CoFe_(1.95)Y_(0.05)O_(4)尖晶石催化剂,在制备Ag_(2)S的过程中采用简单的化学方法制备了异质结Ag_(2)S/CoFe_(1.95)Y_(0.05)O_(4)复合光催化剂。利用X射线衍射仪(XRD)、紫外-可见漫反射光谱仪(UV-Vis DRS)、扫描电子显微镜(SEM)、振动样品磁强计(VSM)、高分辨率透射电镜(HRTEM)对所制备Ag_(2)S/CoFe_(1.95)Y_(0.05)O_(4)进行结构和形态的表征。在可见光照射下降解甲基橙(MO)水溶液,考察制备的光催化剂的光催化活性。结果表明,Ag_(2)S/CoFe_(1.95)Y_(0.05)O_(4)降解甲基橙水溶液的一级动力学常数分别是Ag_(2)S和CoFe_(1.95)Y_(0.05)O_(4)的2.87倍和4.39倍。此外,通过外加磁场可快速从溶液分离出Ag_(2)S/CoFe_(1.95)Y_(0.05)O_(4)复合材料。循环降解实验表明,Ag_(2)S/CoFe_(1.95)Y_(0.05)O_(4)复合材料在光降解过程中具有稳定的降解能力和晶体结构,可循环利用并高效降解有机污染物。

Nano CoFe_(1.95)Y_(0.05)O_(4)spinel catalyst is prepared by using hydrothermal synthesis method,and then Ag_(2)S/CoFe_(1.95)Y_(0.05)O_(4)composite photocatalyst for the formation of heterojunction is prepared by using a simple chemical method in the preparation of Ag_(2)S.The structure and morphology of Ag_(2)S/CoFe_(1.95)Y_(0.05)O_(4)are characterized by means of spectral techniques such as powder X-ray diffraction(XRD),ultraviolet-visible diffuse reflection spectroscopy(UV-Vis DRS),scanning electron microscopy(SEM),vibration sample magnetometer(VSM),and high-resolution transmission electron microscopy(HRTEM).The photocatalytic activity of the prepared photocatalyst is evaluated through degrading methyl orange aqueous solution under the visible light irradiation.The results show that the first-order kinetic constant of Ag_(2)S/CoFe_(1.95)Y_(0.05)O_(4)for degrading methyl orange aqueous solution is 2.87 and 4.39 times that of Ag_(2)S and CoFe_(1.95)Y_(0.05)O_(4),respectively.In addition,Ag_(2)S/CoFe_(1.95)Y_(0.05)O_(4)composites can be rapidly separated from the solution by using an external magnetic field.Cyclic degradation experiment shows that Ag_(2)S/CoFe_(1.95)Y_(0.05)O_(4)composite has stable degradation ability and crystal structure during photodegradation,and can be recycled and degrade organic pollutants efficiently.