阳极氧化TiN薄膜制备N掺杂纳米TiO_2薄膜及其可见光活性

Visible Light Photoelectrochemical Response of Nitrogen-Doped TiO_2 Thin Films Prepared by Anodic Oxidation of Titanium Nitride Films

室温下通过电泳沉积(EPD)的方法在Ti片表面制备TiN薄膜,然后对TiN薄膜进行阳极氧化得到N掺杂多孔纳米结构的TiO2薄膜.利用X射线衍射(XRD),X射线光电子能谱(XPS),扫描电子显微镜(SEM)及光电化学方法对得到的薄膜进行表征.XRD测试结果表明,经过阳极氧化并在350℃空气气氛中退火1h的薄膜中存在锐钛矿晶型的TiO2.XPS的结果表明,样品中的N元素取代部分O,且N的摩尔分数为0.95%.SEM显示,经阳极氧化后薄膜表面出现多孔纳米结构.光电化学测试结果显示,阳极氧化提高了N掺杂TiO2薄膜在可见光下的光电响应.经阳极氧化并热处理的薄膜在0V电位及可见光照射下光电流密度为2.325μA·cm-2,而单纯热处理的薄膜在相同条件下光电流密度仅为0.475μA·cm-2.阳极氧化得到纳米多孔结构提高了N掺杂纳米TiO2薄膜的表面积,从而对可见光的响应增大.

Nanostmctured N-doped TiO2 thin films were obtained by anodic oxidation of titanium nitride films, which were prepared by electrophoretic deposition （EPD） at room temperature on titanium foils. The resultanted thin films were characterized by X-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS）, scanning electron microscopy （SEM）, and photoelectrochemical methods. XRD patterns showed that anatase type TiO2 existed in the thin films after anodic oxidation and annealing at 350 ℃ in air for 1 h. According to XPS residual N atoms partially occupied O atom sites in the TiO2 lattice. A nanostructured surface containing nanosized holes was observed by SEM images of thin films after anodization. The photoelectrochemical response of the N-doped TiO2 thin film was enhanced after anodic oxidation and annealing treatment. The current density under visible light at 0 V was 2.325 μA ·cm^-2 while the current density of thin films only prepared after annealing using the same conditions was 0.475 μA ·cm^-2. The high photoelectrochemical response from visible light of N-doped TiO2 thin films resulted from their nanostructured surfaces that were created after anodic oxidation.