碳含量对C/TiO2复合材料光催化活性的影响

 通过热解单层分散在TiO2表面的蔗糖制得了碳均匀覆盖的C/TiO2复合材料,并采用X射线衍射、紫外-可见漫反射吸收光谱和N2物理吸附等方法对复合材料进行了表征. 以亚甲基蓝和罗丹明B为模型化合物评价了C/TiO2复合材料在紫外和可见光照射下的光催化性能,考察了碳含量对催化活性的影响. 结果表明,光源不同,污染物不同,碳含量不同对催化活性的影响均不相同. 对于考察的三个碳含量的C/TiO2催化剂,在紫外光照射下,前驱体中蔗糖/氧化钛质量比为0.1时制得的C/TiO2光催化降解亚甲基蓝的活性最高,蔗糖/氧化钛质量比为0.2时制得的C/TiO2光催化降解罗丹明B的活性最高; 在可见光照射下,蔗糖/氧化钛质量比为0.05时制得的C/TiO2光催化降解亚甲基蓝和罗丹明B的活性都最高.

Effect of Carbon Content on Photocatalytic Activity of C/TiO2 Composite

A series of carbon-covered titania samples were prepared via pyrolysis of sucrose highly dispersed on titania surface in flowing N_2. The samples were characterized by X-ray diffraction, N_2 adsorption, differential thermal analysis-thermogravimetry, and diffuse reflectance ultraviolet-visible spectroscopy, and their photocatalytic properties were evaluated with two model pollutants, methylene blue (MB) and rhodamine B (RB), at room temperature. The effect of carbon content on photocatalytic activity of the C/TiO_2 composite was investigated. It is found that the effect of carbon content is different for various pollutants or various light sources. For the three tested samples, under the ultraviolet illumination, the C/TiO_2 with sucrose/titania mass ratio of 0.1 in precursor has the highest activity for MB photocatalytic degradation, while in the case of RB, the C/TiO_2 with sucrose/titania mass ratio of 0.2 is most active. Under the visible light illumination, the C/TiO_2 with sucrose/titania mass ratio of 0.05 shows the highest activity for both MB and RB photocatalytic degradation.