二氧化钛包裹碘单质(I2/TiO2)制备及其光催化降解苯酚

采用水热法,以Ti(SO₄)₂为钛源,KIO₃为掺碘剂制备了具有高可见光活性,高稳定性的二氧化钛包裹碘单质(I₂/TiO₂)光催化剂.利用X射线光电子能谱(XPS)、X射线晶体粉末衍射(XRD)、透射电子显微镜(TEM)和紫外可见漫反射光谱(DRS)等表征手段对样品进行表征.结果表明,I₂/TiO₂中除含有锐钛矿相二氧化钛外、还含有碘单质和碘酸;I₂/TiO₂粒径大小为45 nm左右;在波长384 nm至700 nm范围内,该催化剂有强烈的吸收.探讨了该催化剂的形成过程和可见光催化机理.以苯酚降解反应为探针,测定了I₂/TiO₂光催化活性.结果显示:在全谱光源照射下I₂/TiO₂活性略高于P25,在可见光范围内其活性是P25的3倍多.确定了降解苯酚的最佳条件:全谱光源照射,投加量为0.5 g/L,苯酚浓度大于10 mg/L,溶液pH为3.2.I₂/TiO₂重复使用4次后,催化活性没有明显下降.

Preparation of (I2)n Encapsulation Inside TiO2 and Photocatalytic Degradation of Phenol

A simple method for preparing highly visible-light photocatalytic activity and stability nanocrystalline(I2)n encapsulation inside TiO2(I2/TiO2) powders was developed by a mild hydrothermal route.The as-prepared TiO2 powders were characterized by X-ray diffraction(XRD),UV-vis diffuse reflectance spectra(DRS) and transmission electron microscopy (TEM).XRD and TEM measurement revealed that HIO3 and I2 existed in I2/TiO2,the size of I2/TiO2 was about 45.0 nm.I2/TiO2 exhibited obvious a strong absorption in the range of wavelengths from 384 to 700 nm.The formation process of I2/TiO2 and a possible mechanism for the photocatalysis on I2/TiO2 under visible light were proposed.Photocatalytic activity test by degradation of phenol,I2/TiO2 showed much better photocatalytic activity than P25. The conditions of degradation of phenol were optimized as follows: full-spectrum light illumination,quantity of catalysts is 0.5 g/L,initial concentration of phenol is 10 mg/L,the pH of solution is 3.2.