Manipulating solar absorption and electron transport properties of rutile TiO2 photocatalysts via highly n-type F-doping
作者:Wen Qi Fang、Xue Lu Wang、Haimin Zhang、Yi Jia、Ziyang Huo、Zhen Li、Huijun Zhao、Hua Gui Yang、Xiangdong Yao
DOI:10.1039/c3ta13917d
日期:——
In this work, we report a facile and nontoxic one-pot hydrothermal method for synthesizing F-doped rutile single crystalline TiO2 with tuneable solar absorption. The optical band gap of the catalyst can be easily manipulated from 3.05 to 2.58 eV via altering the initial F : Ti molar ratio of reaction precursors. The photoanodes made of rutile TiO2 single crystals with appropriate F-doping concentration show excellent photoelectrocatalytic activity towards water oxidation under ultraviolet and visible light illumination. The best photoelectrocatalytic performance under UV irradiation can be obtained by F-doped TiO2 with an initial F : Ti molar ratio of 0.1, which is almost 15 times higher than that of un-doped TiO2. Further, the F-doped TiO2 photoanodes also exhibit superior photoelectrocatalytic activity under visible irradiation, and the best performance can be achieved by F-doped TiO2 photoanode with an initial F : Ti molar ratio of 0.05. The superior photoelectrocatalytic activity could be attributed to the highly n-type dopant introduced by fluorine, which significantly tunes the electrical conductivities and band structures of the resulting TiO2 photoanodes, and thus the photoelectrocatalytic activities under both UV and visible irradiation. Different techniques have been employed to characterize the electrical conductivity, charge carrier density and band structures of the F-doped rutile TiO2 films, such as photoelectrochemical method, electrical impedance spectroscopy (EIS) measurements, Mott–Schottky plots and XPS valence band spectra.
在这项工作中,我们报告了一种简便、无毒的一锅水热法合成掺杂 F 的金红石单晶 TiO2,该方法具有可调的太阳能吸收能力。通过改变初始 F :钛摩尔比。在紫外线和可见光的照射下,由金红石型二氧化钛单晶制成的光阳极在氧化水方面表现出优异的光电催化活性。初始 F :钛摩尔比为 0.1,比未掺杂的二氧化钛高出近 15 倍。此外,掺杂 F 的 TiO2 光阳极在可见光辐照下也表现出卓越的光电催化活性,初始 F :钛摩尔比为 0.05。卓越的光电催化活性可归因于氟引入的高 n 型掺杂剂,它显著地调整了所得 TiO2 光阳极的电导率和能带结构,从而提高了其在紫外和可见光照射下的光电催化活性。我们采用了不同的技术来表征掺杂氟的金红石二氧化钛薄膜的导电性、电荷载流子密度和能带结构,如光电化学法、电阻抗光谱(EIS)测量、Mott-Schottky 图和 XPS 价带光谱。