碳量子点修饰的二氧化钛纳米片阵列薄膜的构筑及光电化学性能*

为了提高纳米二氧化钛(TiO_2)的光电化学性能,首先采用水热法,以稀盐酸、钛酸丁酯和氟钛酸铵作为原料,在掺杂氟的氧化锡(FTO)导电玻璃上制备了(001)面主导的TiO_2纳米片阵列薄膜。通过电化学腐蚀法制得均一、稳定、高活性碳量子点(carbon quantum dots,CQDs),再通过电泳法将CQDs修饰到TiO_2纳米片阵列薄膜表面,形成CQDs/TiO_2纳米片阵列复合材料。利用扫描电镜(scanning electron microscope,SEM)、 X射线衍射(X-ray diffraction,XRD)、拉曼光谱、X射线光电子能谱(X-ray photoelectron spectroscopy,XPS)和紫外可见光谱(UV-vis)对复合材料的形貌、晶型、表面元素成分和光吸收能力进行表征,通过电化学工作站测试复合材料的光电化学性能。结果表明:CQDs/TiO_2复合材料为锐钛矿晶型,形貌规整均匀;CQDs修饰后TiO_2纳米片的最大吸收波长由388 nm增加到576 nm,光化学能转化率高达2.38%,光电流是TiO_2纳米片的8倍,交流阻抗减小,具有非常优异的光电化学性能。

Construction and Photoelectric Chemical Properties of Carbon Quantum Dot Modified Titanium Dioxide Nanosheet Array Films

The (001) surface-dominated TiO₂ nanometer array films were prepared from dilute hydrochloric acid, butyl titanate and ammonium fluorotitanate by hydrothermal method. The homogeneous, stable, highly active carbon quantum dots(CQDs) were obtained by electrochemical oxidation, and the carbon quantum dots were modified to the surface of the TiO₂ nanometer array film by electrophoresis. The structure of CQDs was characterized by infrared spectroscopy. The morphology and microstructure of the samples were characterized by scanning electron microscope(SEM), X-ray diffraction(XRD) and Raman spectroscopy. The composition of the surface elements of the sample was analyzed by X-ray photoelectron spectroscopy(XPS). The absorption spectrum of the sample was measured by UV-visible spectrophotometer. The photochemical properties of samples were tested by electrochemical workstation. The results show that CQDs contain a large number of hydroxyl groups, carboxyl groups and other oxygen-containing groups; The prepared TiO₂ nanometer sheet is an acute titanium ore crystal; XPS shows that the sample contains elements C, Ti and O. After the CQDs modification, the maximum absorption wavelength of the TiO₂ nanometer increases from 388 nm to 576 nm, the impedance decreases, the photocurrent increases. It is proved that the CQDs/TiO₂ has better photochemical properties.