Abstract
以四氯化钛(TiCl4)钛源,采用水热法制备了具有优异光催化性能的板钛矿/锐钛矿混晶TiO2。利用X射线衍射、拉曼光谱、透射电镜、比表面积分析、紫外漫反射光谱等测试手段对所得样品进行了表征。以亚甲基蓝溶液为目标降解物,在紫外灯照射下测试了所得样品的光催化活性。实验结果表明,所得样品为混晶纳米TiO2,由锐钛矿纳米颗粒和板钛矿纳米棒组成,其比表面积为78.72 m2·g-1,孔体积0.439 m3·g-1,平均孔径为22.32 nm,禁带宽度值为3.287 eV。混晶纳米TiO2展示了非常高的光催化活性,在紫外灯照射60 min后,对亚甲基蓝溶液的降解率高达99.0%。混晶纳米TiO2的高光催化活性不仅得益于其较大的比表面积,还源于板钛矿与锐钛矿结构间存在一定协同效应,后者为光生电子在不同相结构间的转移提供了便利,进而抑制了光生电子–空穴的复合。 In this paper, brookite/anatase TiO2 mixtures with excellent photocatalytic property were synthesized via hydrothermal method. X-ray powder diffraction (XRD), Raman spectroscopy, transmission electron microscopy (TEM), Brunauer Emmett and Teller (BET) surface area analysis and ultraviolet-visible (UV-vis) spectroscopy were used to characterize the sample. The photocatalytic activity of brookite/anatase mixtures was evaluated by photodegradation of methylene blue (MB) under ultraviolet light irradiation. Experimental results showed that theobtained sample was the mixed crystal TiO2, which consisted of brookite nanorods and anatase nanoparticles. The specific surface area is 78.72 m2·g-1, the pore volume is 0.439 m3·g-1, and the average pore size is 22.32 nm. The band value of thebrookite/anatase mixtures is 3.287 eV. The brookite/anatase mixtures showed very high photocatalytic activity and the photocatalytic degradation rate of MB solution reached to 99.0% after UV light illumination for 60 min. The higher photocatalytic activity can be attributable to not only its large specific surface area but also the synergistic effect between brookite and anatase TiO2 phases, and the latter allowed an easier transfer of photogenerated electrons from one phase to another, consequently inhibiting the recombination of electrons and holes pairs.