| Titanium dioxide (TiO2) is one of the most potential semiconductors used in photocatalysis, but the photocatalytic efficiency still needs improvement. Recent years have seen a large variety of technologies in the improvement of photocatalytic efficiency of TiO2. Among these technologies, engineering the specific exposed surfaces of TiO2has received significant attention. Herein, we succeeded in the preparation of anatase TiO2with different ratio of clean{001} and{101} facets.In order to study the relationship between the two facets and their adsorption and photocatalytic capabilities, we choose the samples with dominant{001} and {101} facets to research the mechanism. 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 TiO2with dominant{001} facets exhibits higher toluene adsorption capacity than TiO2with dominant{101} facets, which may be attributed to the different number of unsaturated5c-Ti capable of forming the main active adsorption sites (terminal Ti-OH species). TiO2with dominant{001} facets shows a significantly high photocatalytic degradation performance, with its degradation rate being6times 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. |
PDF Full Text Request