TiO_2-聚吡咯复合材料的制备及光催化性能

Preparation and Photocatalytic Properties of TiO_2-Polypyrrole Composite Materials

采用原位氧化聚合法制备TiO2-聚吡咯复合材料,研究吡咯与TiO2配比对TiO2-聚吡咯复合材料在紫外光和太阳光下光催化降解甲基橙的影响,利用傅里叶红外光谱仪、X射线衍射仪、紫外-可见光谱仪对样品进行表征。结果表明,TiO2-聚吡咯复合材料与纯聚吡咯相比,聚吡咯本征态特征峰和C─N伸缩振动峰峰值都向高波数偏移,TiO2和聚吡咯的复合并不是单纯的物理复合,而是产生了化学作用力;通过改变吡咯的添加量,可以控制聚吡咯在TiO2粉体表面的包覆量,聚吡咯的包覆对TiO2的晶型没有影响;聚吡咯对TiO2的包覆可降低TiO2的禁带宽度至2.90 eV,使TiO2-聚吡咯复合材料可吸收的波长范围拓宽到可见光区,提高复合材料在可见光下的光催化能力;适量的聚吡咯包覆可以提高TiO2-聚吡咯复合材料的光催化活性,以紫外灯作为光源催化降解甲基橙,当吡咯包覆质量分数为0.06时,复合材料的电子-空穴对分离效果最好;以太阳光作为光源催化降解甲基橙,当吡咯包覆质量分数为0.04时,复合材料的光谱拓展效果最好。

TiO2-polypyrrole composite materials were prepared by in situ oxidation polymerization.The impact of the ratios of pyrrole and TiO2 on the photocatalytic properties of TiO2-polypyrrole composite materials were studied by the degradation of methyl orange under UV light and sunlight.The composite materials were characterized by FTIR,X ray diffractometry and UV-Vis spectroscopy.The results indicate that comparing TiO2-polypyrrolecomposite materials with pure polypyrrole,both eigenstate characteristic peaks of polypyrrole and stretching vibration peak value of C—N shift to high wave numbers.The composition of TiO2 and polypyrrole is not pure physical composition.A chemical reaction between them is produced.The coating amount of polypyrrole on surface of TiO2 powders can be controlled by changing adding amount of pyrrole.The coating of polypyrrole has no effect on crystal form of TiO2.The coating of polypyrrole can reduce the band gap of TiO2 to 2.90 eV.The absorbable wave range of TiO2-polypyrrole composite materials can be broadened to the range of visible light.The photocatalytic capability of composite materials under visible light can be improved.The right coated amount of polypyrrole can improve the photocatalytic activity of TiO2-polypyrrole composite materials.Catalytic degradation of methyl orange with an ultraviolet lamp as light source,when the mass fraction of pyrrole coating is 0.06,separation effect of electron-hole pair of composite materials is best.Catalytic degradation of methyl orange with sunlight as light source,when the mass fraction of pyrrole coating is 0.04,spectral expansion effect of composite materials is best.