等离子体修饰磁载TiO_2光催化剂性能研究

摘要

A core-shell CoFe_2O_4/TiO_2 magnetic nano-photocatalyst was prepared by hydrolysis of titanium tetrachlor-ide in the presence of the CoFe_2O_4 magnetic particles and modified by cold plasma. The magnetic property of the samples was characterized by Vibrating Sample Magnetometer (VSM) analysis. The CoFe_2O_4/TiO_2 magnetic nano-photocatalysts has fairly good magnetic property. The X-ray diffraction (XRD), transmission electron microscopy (TEM) and ultraviolet-visible (UV-Vis) technique were used to analyze the phase structure, size and spectrum response scope of the samples. The XRD indicated the anatase TiO_2 was formed when TCF modified by plasma. The size of CoFe_2O_4particles was about 20 nm. The diameter of CoFe_2O_4/TiO_2 particles is in the range of 30～40 nm. So the shell of TiO_2 enwraps closely around the core and the thickness is in the range of 10～20 nm. The UV-Vis spectrum revealed a red shift of the absorption edge to the visible-light region than that pure TiO_2. Methyl orange was used to investigate the photo-degradation activity of the nano-photocatalysts. The results showed that the photocatalytic activity of TCF modified by plasma is better than that without plasma.%以化学共沉法制备的CoFe_2O_4纳米粒子为磁核,采用TiCl_4水解包覆技术制备磁载二氧化钛纳米复合粒子CoFe_2O_4/TiO_x(TCF),利用低温等离子体技术修饰TCF制备了CoFe_2O_4/TiO_2(PTCF)纳米复合光催化剂.运用VSM(振动样品磁强计)技术对样品磁性能进行研究,结果表明:等离子体修饰后的复合材料仍具有较高的饱和磁化强度,可在外加磁场作用下实现催化剂在水中的分离与回收;样品的XRD、TEM和UV-Vis分析测试结果表明:等离子体修饰后的复合材料有锐钛矿型TiO_2存在;TEM谱图显示磁核CoFe_2O_4的平均粒径约为20 nm,TCF复合粒子的粒径约为30～40 nm,TiO_2包覆层的厚度为10～20 nm.与纯TiO_2相比PTCF样品对光的吸收拓展到整个紫外-可见区,扩大了光谱响应范围;对甲基橙溶液降解的光催化活性评价研究表明:TCF复合粒子等离子体修饰后的PTCF纳米复合光催剂的光催化活性明显提高.