等离子体修饰磁载TiO2光催化剂性能研究

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 /TiO_x(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。

Magnetically Separable TiO2 Photocatalysts Modified by Plasma and Its Characterization

A core-shell CoFe₂O₄/TiO₂ magnetic nano-photocatalyst was prepared by hydrolysis of titanium tetrachlor-ide 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 CoFe₂O₄ particles 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.