Preparation and Photocatalytic Properties of Black TiO2 Photonic Crystals with Inverse Opal Structure
In this research,the TiO2 photonic crystal with reverse opal structure was pre-pared by a hard template method,and then was hydrogenated to obtain the black TiO2 pho-tonic crystal(H-IO TiO2).From some characterizations including X-ray diffraction pat-terns,scanning electron microscopy and X-ray photoelectron spectroscopy,a large number of Ti3+ ions and O vacancy defects were found on the surface of H-IO TiO2,which can result in an obvious red shift of the absorption spectrum.The photocatalytic activity of the catalyst was evaluated by the photocatalytic degradation of organic dyes.It was found that the degra-dation of dye rhodamine B(RhB)accorded with the pseudo first-order kinetics,and H-IO TiO2 showed the strongest photocatalytic activity(0.033 min-1 for the rate constant),which was 2.4 and 1.2 times of untreated TiO2(0.014 min-1 for the rate constant)and air heat-treated catalyst(0.028 min-1 for the rate constant),respectively.Free radical quench-ing experiments showed that more oxidizing species could be produced by H-IO TiO2 under light,especially·O-2 and·OH radicals.In addition,it was also proved that the existence of surface defects in H-IO TiO2 could significantly accelerate the oxygen reduction process.As a result,the photocatalytic activity of H-IO TiO2 was greatly improved.
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