响应面法优化TiO2纳米管光电极制备及光电催化性能研究

Optimized Preparation of TiO2-NTs Photoelectrode by Response Surface Method and Its Property of Photocatalytic Degradation

为了探究采用阳极氧化法制备的TiO2-NTs(TiO2纳米管)光电极的光电催化性能,以单因素法考察了φ(H2O)、w(氟化铵)、氧化温度和氧化时间4个因素对其光电催化性能的影响,并采用Box-Behnken模型的PSM(响应面法)对TiO2-NTs的制备条件进行优化,进一步通过SEM(扫描电子显微镜)、XRD(X射线衍射)对TiO2-NTs进行表征,研究了其在紫外光下对亚甲基蓝的光电催化效果.结果表明:①应用Box-Behnken模型可知,TiO2-NTs最佳制备条件为φ(H2O)43%、w(氟化铵)0.5%、氧化温度38℃、氧化时间1.72 h.此条件下制备的TiO2纳米管光电极2 h处理亚甲基蓝的降解效率预测值为73.53%,对其光电催化能力进行验证,实际处理效率为73.2%,误差率仅为0.4%.②φ(H2O)和w(氟化铵)对TiO2-NTs光电极催化活性有显著影响.③SEM、XRD分析显示,TiO2具有管状结构且分布均匀,经测量纳米管管径约为61.30~118.00 nm,平均值为83.99 nm,管壁为19.08 nm,同时部分锐钛矿相转变成金红石相.研究显示,TiO2-NTs对亚甲基蓝有良好的光电催化效果.

In order to explore the influence of preparation conditions by anodic oxidation method on the photoelectrocatalytic performance of TiO2-NTs(TiO2 nanotube)photoelectrode,four single factors,includingφ(H2O),w(ammonium fluoride),oxidation temperature and oxidation time were investigated by a single factor method.The preparation conditions of TiO2-NTs by anodic oxidation was optimized according to the Box-Behnken model of the response surface method.SEM(scanning electron microscope)and XRD(X-ray diffraction)were used to characterize the TiO2-NTs catalyst,and the photoelectrocatalytic effect of these photoelectrodes on methylene blue under ultraviolet light was further studied.The results showed that:(1)According to the Box-Behnken model,the optimum preparation conditions were 43%water content,0.5%of ammonium fluoride,oxidation temperature 38℃and oxidation time 1.72 h.The predicted value of methylene blue degradation ratio was 73.53%after 2 h treatment of the TiO2-NTs.The photoelectrocatalytic ability was verified and the actual treatment effect was 73.2%.The error rate was only 0.4%.(2)φ(H2O)and w(ammonium fluoride)significantly affected the photoelectrocatalytic property of TiO2-NTs.(3)SEM and XRD analyses showed that TiO2 had a tubular structure and a uniform distribution.The diameter of the nanotubes was about 61.30-118.00 nm with average diameter of 83.99 nm.The tube wall was about 19.08 nm.At the same time,anatase was partially transformed into rutile.The results showed that TiO2-NTs had a good photoelectrocatalytic effect on the treatment methylene blue.