National Center for Nanoscience and Technology, Beijing 100190, China.
Phys Chem Chem Phys. 2013 Dec 14;15(46):20037-45. doi: 10.1039/c3cp53531b.
The chromium doped titanium dioxide (Cr-TiO2) has been synthesized using a hydrothermal method. The as-prepared samples have been characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution TEM (HR-TEM), XPS valence band spectroscopy, UV-vis diffuse reflectance spectroscopy (UV-vis DR), photoluminescence (PL) spectroscopy and time resolved PL (TR-PL) spectroscopy. The doping mechanism and related influence on the photocatalytic performance of TiO2 are thus proposed. The doped Cr(3+) ions can replace the Ti atoms in the lattice with oxygen vacancy compensation, distribute homogeneously in the framework of TiO2 crystals, and may make the n-type TiO2 less n-type or more p-type due to the resultant formation of oxygen vacancies, resulting in absorption of visible light, decrease of the intensity of PL emission and prolonged lifetime of photogenerated charge carriers. Compared with TiO2, the doped samples exhibit an improved visible-light photocatalytic activity. The influence of nitrogen modification has also been studied. We envision that these results would afford a better understanding of the doping mechanism of TiO2 using metal ions and, therefore, may provide a feasible way to prepare the TiO2-based photocatalysts for real applications.
采用水热法合成了掺铬二氧化钛（Cr-TiO2）。通过 X 射线光电子能谱（XPS）、X 射线衍射（XRD）、透射电子显微镜（TEM）、高分辨率 TEM（HR-TEM）、XPS 价带光谱、紫外可见漫反射光谱（UV-vis DR）、光致发光（PL）光谱和时间分辨 PL（TR-PL）光谱对所制备的样品进行了表征。提出了掺杂机制及对 TiO2 光催化性能的相关影响。掺杂的 Cr（3+）离子可以通过氧空位补偿替代晶格中的 Ti 原子，均匀分布在 TiO2 晶体的骨架中，并且由于形成氧空位，可能使 n 型 TiO2 带隙减小，更接近 p 型，从而导致可见光吸收、PL 发射强度降低和光生载流子寿命延长。与 TiO2 相比，掺杂样品表现出了更好的可见光光催化活性。还研究了氮改性的影响。我们预计这些结果将有助于更好地理解金属离子掺杂 TiO2 的机制，从而为实际应用中制备基于 TiO2 的光催化剂提供一种可行的方法。
