Ye Liqun, Mao Jin, Peng Tianyou, Zan Ling, Zhang Youxiang
College of Chemistry and Molecular Science, Wuhan University, Wuhan 430072, People's Republic of China.
Phys Chem Chem Phys. 2014 Aug 7;16(29):15675-80. doi: 10.1039/c4cp01488j.
We firstly demonstrate the opposite photocatalytic activity orders of low-index facets of anatase TiO2 in the liquid phase for rhodamine B (RhB) photocatalytic degradation and in the gaseous phase for the photoreduction of CO2 to CH4. The photocatalytic activity order in the liquid phase for RhB photocatalytic degradation is revealed as {001} > {101} > {010}, whereas the photocatalytic activity order {010} > {101} > {001} is found in the gaseous phase for the photoreduction of CO2 to CH4. The atomic arrangement of the different facets, UV-vis diffuse reflectance spectra, photoluminescence spectra and attenuated total reflectance Fourier transform infrared spectroscopy analysis show that the photoactivity order in the gas phase for the photoreduction of CO2 to CH4 mainly depends on the CO2 molecule adsorption properties on the different exposed facets, and the separation efficiency of the photo-generated carriers determines the photoactivity order for the dye degradation reaction in the liquid phase. These findings also provide a new direction to design efficient photocatalysts and the tuning of their photoreactivity for environmental and energy applications.
我们首先证明了锐钛矿型TiO₂低指数晶面在液相中对罗丹明B（RhB）光催化降解以及在气相中对CO₂光还原为CH₄表现出相反的光催化活性顺序。液相中RhB光催化降解的光催化活性顺序为{001} > {101} > {010}，而气相中CO₂光还原为CH₄的光催化活性顺序为{010} > {101} > {001}。不同晶面的原子排列、紫外-可见漫反射光谱、光致发光光谱以及衰减全反射傅里叶变换红外光谱分析表明，气相中CO₂光还原为CH₄的光活性顺序主要取决于不同暴露晶面上CO₂分子的吸附性质，而光生载流子的分离效率决定了液相中染料降解反应的光活性顺序。这些发现也为设计高效光催化剂及其光反应活性的调控以用于环境和能源应用提供了新方向。
