【摘要】 以TiCl4、Fe(NO3)3·9H2O和Na2SiO3 9H2O为原料,采用溶胶凝胶法结合超临界流体干燥法(SCFD)制备了纳米级TiO2/Fe2O3和TiO2/Fe2O3/SiO2复合光催化剂。以光催化降解苯酚对所得催化剂的催化活性进行了评价。结果表明,纳米TiO2/Fe2O3复合粒子与单组分TiO2比较,复合粒子光催化活性高于单组分的TiO2,6h苯酚降解率高达95 9%。SiO2的加入可以抑制纳米粒子粒径的长大和晶相的转变,增强TiO2纳米粒子的热稳定性。复合光催化剂中Fe2O3最佳掺入量为0 06%,SiO2最佳掺入量为10%(摩尔分数)。并用XRD、TEM和FTIR等手段进行了表征。TiO2以锐钛矿型形式存在,SiO2以无定性形式存在。比较了不同制备方法制得的TiO2/Fe2O3复合光催化剂,得出超临界干燥法制备的光催化剂具有粒径小、比表面积大、分散性好、光催化活性高等特点。采用超临界流体干燥可直接得锐钛型纳米复合光催化剂。更多还原

【Abstract】 TiO₂/Fe₂O₃ and TiO₂/Fe₂O₃/SiO₂ nanocomposite photocatalysts were prepared with Na₂SiO₃·9H₂O,Fe（NO₃）₃·9H₂O and TiCl₄ as precursors by chemistry coating processes and supercritical fluid drying（SCFD）methods. The photocatalytic activity was evaluated by photocatalytic degradation of phenol as model reaction. Characterizations with XRD,TEM and FTIR show that in addition to anatase type TiO₂ is also formed in the range of the studied doping concentration, and SiO₂ remains amorphous at all samples. It could hold up the growth of the nanoparticle size and transformation from anatase to rutile.Compared with pure TiO₂,or TiO₂/Fe₂O₃ catalyst prepared by sol-gel method,nano-composite photocatalyst shows significant improvement in catalytic activity: The photocatalytic degradation rate of phenol in 6 h reached 95.9%. The optimum doping of Fe₂O₃ is 0.06%.Application of the TiO₂/Fe₂O₃/SiO₂ composite catalysts for the photocatalytic decomposition of phenol could not only give the same activity relative to pure ultrafine TiO₂, but also reduce cost. The experimental results prove that the thermal stability of TiO₂ is greatly enhanced after mixing with slight amount of SiO₂ .The optimum doping of SiO₂ is 10.0%.The photo-catalytic particles prepared by SCFD combination technology have small size, large surface area and high activity.更多还原