控制胶体合成法制备掺铁TiO_2粉末及光催化降解甲基橙

Iron-Doped TiO_2 Photocatlysts Prepared by Controlled Colloidal Synthesis Method for Photocatalytic Degradation of Methyl Orange

分别采用控制胶体合成法和溶胶-凝胶法制备了2种不同掺铁方式的TiO2粉末,并用XRD、TEM、BET、UV-Vis、FS等技术对样品进行了表征。在紫外光照射下,以甲基橙溶液的光催化降解反应为探针,研究了掺Fe离子浓度、包覆的次数、不同掺杂方式对样品光催化活性的影响。结果表明,以均匀掺铁TiO2(铁含量大于0.02mol%)干凝胶粉末为载体,采用控制胶体合成法制备了具有P-N结型结构的非均匀掺铁TiO2粉末,其光催化活性较均匀掺杂TiO2粉末明显提高,并且随着包覆次数(≤3次)的增加而增强,以0.04mol%掺铁TiO2粉末包覆3次后制备的样品具有最佳光催化活性,其表观速率常数是未掺杂的TiO2粉末的5.32倍,是具有相同Fe含量的均匀掺杂TiO2粉末的4.58倍。

Two kinds of iron （Ⅲ）-doped TiO2 powders were prepared by sol-gel and controlled colloidal synthesis method（CCS）, and were characterized by XRD, TEM, BET, UV-Vis（DRS） and FS spectroscopy. The photocatalytic activity was evaluated using methyl orange photodegradation in aqueous suspensions under UV irradiation as a probe reaction. The influence of iron content, coating times and doping modes on the photocatalytic activities was investigated. The CCS-derived Fe3＋-doped TiO2 is shown to have much higher photocatlytic destruction rate than that of Fe3＋-doped TiO2in uniform doping mode and undoped TiO2. The photocatalytic activity of CCS-derived Fe3＋-doped TiO2 is enhanced with the increase in coating times. 3-0.04%Fe-TiO2/C has the best photocatalytic activity with an apparent rate constant about 5.32 times as large as that of undoped TiO2, and about 4.58 times as large as that of TiO2 doped by Fe uniformly with the same iron content.