掺杂Fe2O3对吸附相反应技术制备TiO2的形貌和光催化性能的影响

利用吸附相反应技术制备得到了掺杂不同浓度的Fe₂O₃的TiO₂复合光催化剂。通过透射电子显微镜(TEM)、紫外可见光谱和X射线衍射(XRD)研究不同掺杂浓度对TiO₂形貌和结晶过程的影响，并利用3种波长光源下的甲基橙光降解实验考评了各个复合光催化剂的催化活性。结果表明，掺杂后复合光催化剂中Fe₂O₃分散性较好较均匀。在TiO₂紫外可见吸收光谱中由于Fe₂O₃的掺杂而出现了红移，而且随着掺杂浓度增加红移越来越明显，复合光催化剂的禁带宽度也越来越小。在焙烧过程中无定形Fe₂O₃或Fe³⁺进入了TiO₂的晶格结构，从而抑制了TiO₂的结晶过程。半导体禁带宽度的减少以及TiO₂结晶过程的抑制作用，都导致紫外光下复合光催化剂催化活性的降低。但Fe₂O₃的掺杂也使得复合光催化剂在可见光区出现了一定的光催化活性。

Influence of Fe2O3 Doping on Morphology and Photocatalytic Activity of TiO2 Prepared by Adsorption Phase Synthesis

TiO₂ photocatalysts doped with Fe₂O₃ were prepared by adsorption phase synthesis (APS). The influence of Fe₂O₃ concentration on morphology and crystallization of TiO₂ was explored by TEM, UV-Vis and XRD. The activities of these photocatalysts were evaluated by photodegradation of methyl-orange irradiated under three wavelengths of light. The results suggest that the distribution of Fe₂O₃ in composite photocatalysts is homogeneous. Red shifts appear in UV-Vis absorpion of TiO₂ after Fe₂O₃ doping and the red shift becomes obvious with increasing, in concentration of Fe₂O₃ , thus leading to decrease in the band gap of composite photocatalysts. Due to the entry of amorphous Fe₂O₃ or Fe³⁺ into lattice structure of TiO₂, the crystallization of TiO₂ is restricted. Both the decrease of band gap and the restriction on TiO₂ doped with Fe₂O₃ would depress the activity of photocatalysts when irradiated at two wavelengths of UV light. However, Fe₂O₃ doping also leads to a certain activity of photocatalysts under visible light.