TiO_2/α-Fe_2O_3复合光催化剂的制备及表征

PREPARATION AND CHARACTERIZATION OF TiO_2/α-Fe_2O_3 PHOTOCATALYST

用溶胶–凝胶法在α-FeOOH上负载TiO2,经过煅烧制备了TiO2/α-Fe2O3光催化剂。用Brunauer–Emmett–Teller(BET)法测试氮吸附比表面积。用X射线衍射、透射电镜、扫描电镜、Fourier转换红外光谱等研究了不同煅烧温度制备的光催化剂物相组成和形貌特征。研究了不同煅烧温度制备的光催化剂对活性艳蓝X–BR染料的吸附和光催化性能。结果表明:与未负载TiO2的α-FeOOH相比,经过复合、350℃煅烧制备的TiO2/α-Fe2O3复合材料的比表面积有了显著增加,从35.4m2/g增加到167.7m2/g,但是,当温度高于450℃时,其比表面积又有所下降。随着煅烧温度的增加,其负载的TiO2晶型由锐钛矿转变为金红石型,粒径也逐渐增大。在煅烧温度为350℃时,TiO2/α-Fe2O3催化剂吸附和光催化性能最好,脱色率可达到85.19%。

TiO2-coated goethite （α-FeOOH） was prepared through the sol-gel method and subsequent heat treatment. The TiO2/α-Fe2O3 was characterized using Brunauer-Emmett-Teller （BET） method, X-ray diffraction, transmission electron microscope, scanning electron microscope, and Fourier transform infrared spectroscopy. Adsorbing and photocatalytic ability was studied when the specimens were treated with active blue X-BR using TiO2/α-Fe2O3 calcination at different temperatures. The results indicate that the BET surface area of TiO2/α-Fe2O3 after calcination increases dramatically in comparison with the original α-FeOOH. The surface area increases from 35.4 m^2/g to 167.7 m^2/g when calcines at 350 ℃ but decreased when calcines at 450 ℃. Crystalline TiO2 coated on α-FeOOH is from anatase to rutile and the average crystallite size increases gradually with the increasing of heat treatment temperatures. The absorption and photocatalytic activity of TiO2/α-Fe2O3 for active blue X-BR under ultraviolet irradiation were studied. The results show that the highest photocatalytic activity and absorption of TiO2/α-Fe2O3 are obtained at a calcination temperature of 350 ℃ and the decolorization rate reaches 85.19%.