等离子体修饰磁载TiO_2光催化剂性能研究

Magnetically Separable TiO_2 Photocatalysts Modified by Plasma and Its Characterization

以化学共沉法制备的CoFe2O4纳米粒子为磁核,采用TiCl4水解包覆技术制备磁载二氧化钛纳米复合粒子CoFe2O4/TiOx（TCF）,利用低温等离子体技术修饰TCF制备了CoFe2O4/TiO2（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TiO2存在;TEM谱图显示磁核CoFe2O4的平均粒径约为20 nm,TCF复合粒子的粒径约为30～40 nm,TiO2包覆层的厚度为10～20 nm。与纯TiO2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。

A core-shell CoFe2O4/TiO2 magnetic nano-photocatalyst was prepared by hydrolysis of titanium tetrachloride in the presence of the CoFe2O4 magnetic particles and modified by cold plasma. The magnetic property of the samples was characterized by Vibrating Sample Magnetometer （VSM） analysis. The CoFe2O4/TiO2 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 TiO2 was formed when TCF modified by plasma. The size of CoFe2O4particles was about 20 nm. The diameter of CoFe2O4/TiO2 particles is in the range of 30-40 nm. So the shell of TiO2 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 TiO2. 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.