碳掺杂TiO2纳米管电极的简易制备及其光电化学性能

通过阳极氧化方法制备了TiO₂纳米管薄膜, 在NaHCO₃存在下对该薄膜进行热处理得到碳掺杂TiO₂(C-TiO₂)纳米管薄膜, 通过X射线衍射仪(XRD)、扫描电子显微镜(SEM)、X射线光电子能谱(XPS)、紫外-可见漫反射光谱、电化学阻抗谱(EIS)和Mott-Schottky等方法对得到的薄膜进行表征。XRD结果表明C-TiO₂纳米管薄膜中的TiO₂主要为锐钛矿晶型; SEM结果显示薄膜存在纳米管结构; XPS分析表明C-TiO₂纳米管薄膜中的C以替代型掺杂形式进入到TiO₂晶格中; 光电化学性能测试显示, 相对于TiO₂纳米薄膜, C-TiO₂阻抗减小, 平带电位由-0.28 V负移至-0.38 V, 具有更好的紫外-可见光和可见光响应, 紫外-可见光下的光电流是未掺杂的1.7倍。利用阳极氧化的Ti丝作为光阳极和Pt丝作为对电极组装了染料敏化太阳能电池并进行了性能测试, 结果表明, 经过碳掺杂的Ti /TiO₂丝为光阳极电池的短路电流密度和电池效率分别达到0.17 mA/cm²和3.8%, 较未掺杂的Ti/TiO₂丝为光阳极的电池的短路电流密度和电池效率均增大, 表明适量的碳掺杂有利于提高电池效率。

Facile Preparation Carbon-Doped TiO2 Nanotube Electrodes and Its Enhanced Photoelectrochemical Response

Nanostructured carbon-doped titanium dioxide were fabricated by thermal treatment of anodized titanium dioxide nanotube with the presence of NaHCO₃. The resulted samples were characterized via X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, UV-Vis diffuse reflectance spectra, electrochemical impedance spectroscopy and photoelectrochemistry methods. Anatase type TiO₂ nanotubes and almost no influence from C doping were observed from XRD and SEM results. XPS spectra showed that the O was partly replaced by C in the resulted carbon-doped titanium dioxide nanotubes. Enhanced photocurrents were identified for the C-TiO₂ nanotube and 1.7 times was observed in comparison to the TiO₂. Electrochemical impedance spectroscopy indicates the decrease of charge transfer resistance and flat band potential also negative shift from -0.28 V to -0.38 V. Needle- shaped dye sensitized solar cells were developed by using anodized Ti and Pt wire. Improved photovoltaic performance was demonstrated by the photocurrent density-photovoltage curves for DSSCs when the anodized Ti wire was thermal treated with the presence of NaHCO₃. The short-circuit current and energy conversion efficiency were up to 0.17 mA/cm² and 3.8%, respectively.