Preparation and photocatalytic activity of rutile TiO2 and goethite composite photocatalysts

Rutile TiO2 and goethite (α-FeOOH) composite photocatalysts were fabricated by hydrolysis and precipitation using titanium tetrachloride as a precursor and α-FeOOH as a support. The samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. The results show that at lower temperature, rutile TiO2 particles coat on the surface of α-FeOOH particles to form rutile TiO2-α-FeOOH composite photocatalyst. At higher temperature, iron ions are doped into the rutile TiO2 lattice to form iron-doped rutile TiO2 tubes; at medium temperature, the sample is a mixture with both composite and iron-doped structures. The photocatalytic activity of the samples is estimated by their ability to degrade methyl orange under irradiation with ultraviolet-visible light (200–800 nm) at ambient temperature. The photocatalytic activities of the samples are improved compared with that of pure rutile TiO2 and α-FeOOH. The sample containing a mixture of composite and iron-doped structures shows the highest photocatalytic activity of that investigated. As a result, the photocatalytic activity of Ti2O could be improved effectively by combining with α-FeOOH or doping iron.

摘要以四氯化钛为钛源, 针铁矿(帽-FeOOH)为载体, 采用水解沉淀法制备了金红石相二氧化钛(Ti2O)与帽-FeOOH的复合光催化材料, 并采用X射线衍射/扫描电子显微镜/透射电子显微镜/X射线能量散射谱和X射线光电子能谱对样品进行了表征. 结果表明, 低温下, 金红石相Ti2O包覆于帽-FeOOH表面, 并形成复合结构; 较高温下, 铁离子进入金红石相Ti2O晶格, 并形成铁掺杂金红石相Ti2O纳米管; 中温下, 样品兼有复合和掺杂两者特征. 在室温下以甲基橙为降解对象, 采用钨灯+氘灯(波长200–800 nm)为光源, 对样品的光催化活性进行了测试. 结果表明, 样品对甲基橙的光催化降解效果良好; 与纯帽-FeOOH和金红石相Ti2O相比, 不同结构样品的光催化活性均有所提高, 其中, 复合兼掺杂型样品的光催化活性最高. 由此可见, 与帽-FeOOH复合和铁掺杂是提高Ti2O光催化活性的有效途径. 

Graphical AbstractThe structure of rutile TiO2 and α-FeOOH composite photocatalysts can be controlled by adjusting reaction temperature, and their photocatalytic activity is maximized when they possess a core-shell structure with Fe3+ doping.Figure optionsDownload as PowerPoint slide