碳掺杂TiO_2纳米管电极的简易制备及其光电化学性能

Facile Preparation Carbon-Doped TiO_2 Nanotube Electrodes and Its Enhanced Photoelectrochemical Response

通过阳极氧化方法制备了TiO2纳米管薄膜,在Na HCO3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 m A/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。

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, scan- ning electron microscopy, X-ray photoelectron spectroscopy, UV-Vis diffuse reflectance spectra, electrochemical im- pedance 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 dem- onstrated 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.