Wang Mengjiao, Zhang Fan, Zhu Xiaodi, Qi Zeming, Hong Bin, Ding Jianjun, Bao Jun, Sun Song, Gao Chen
CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science & Technology of China , Hefei, Anhui 230026, China.
Langmuir. 2015 Feb 10;31(5):1730-6. doi: 10.1021/la5047595. Epub 2015 Jan 28.
Effective adsorption is of great importance to the photocatalytic degradation of volatile organic compounds. Herein, we succeeded in the preparation of anatase TiO2 with clean dominant {001} and {101} facets. By using in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) equipped with a homemade reaction system and a coupling gas-dosing system, we found that TiO2 with dominant {001} facets exhibits higher toluene adsorption capacity than TiO2 with dominant {101} facets, which may be attributed to the different number of unsaturated 5c-Ti capable of forming the main active adsorption sites (terminal Ti-OH species). TiO2 with dominant {001} facets shows a significantly high photocatalytic degradation performance, with its degradation rate being 6 times higher than that of dominant {101} facets. Combined with simulation results, it is suggested that the synergetic effects of the formation of specific active adsorption sites, the low adsorption energy for toluene, and preservation of the free molecularly adsorbed water on the surface promote the degradation of gaseous toluene on the dominant {001} facets. This study exemplifies that the facet-dependent adsorption of volatile organic compounds is one of the most important factors to effectively engineer photocatalysts for air purification.
有效的吸附对于挥发性有机化合物的光催化降解至关重要。在此，我们成功制备了具有清洁主导{001}和{101}晶面的锐钛矿型TiO₂。通过使用配备自制反应系统和耦合气体进样系统的原位漫反射红外傅里叶变换光谱（DRIFTS），我们发现具有主导{001}晶面的TiO₂比具有主导{101}晶面的TiO₂表现出更高的甲苯吸附容量，这可能归因于能够形成主要活性吸附位点（末端Ti-OH物种）的不饱和5c-Ti数量不同。具有主导{001}晶面的TiO₂显示出显著高的光催化降解性能，其降解速率比主导{101}晶面的高6倍。结合模拟结果表明，特定活性吸附位点的形成、甲苯的低吸附能以及表面自由分子吸附水的保留的协同作用促进了气态甲苯在主导{001}晶面上的降解。本研究表明，挥发性有机化合物的晶面依赖性吸附是有效设计用于空气净化的光催化剂的最重要因素之一。
