氧气热处理的TiO2纳米管阵列光电催化降解亚甲基蓝的研究

采用原位阳极氧化法在Ti基底上制备了高度有序的TiO2纳米管阵列薄膜,SEM图像表明TiO2纳米管定向排列整齐,分布均匀,其管径范围在70～100 nm.XRD结果证明,阳极氧化法制备的TiO2纳米管为无定型晶型,经退火后为具有良好光催化活性的锐钛矿型.以亚甲基蓝（methylene blue）为目标物研究了TiO2纳米管光电催化性能及影响因素,结果表明,以0.1 mol/L NaCl为电解质,在氧气热处理气氛下,外加偏压为0.5 V、pH=3.25、光照强度为1 000μW/cm2、纳米管薄膜表面积为2 cm×2 cm且MB初始浓度为10 mg/L的条件下,TiO2纳米管阵列薄膜光电催化降解MB的降解效率可达99.56%.电化学阻抗谱分析显示,光电催化降解过程的速控步骤均为表面反应步骤,外加偏压减小了界面电荷转移阻抗,提高了光生载流子的分离效率.

Research of the Photoelectrocatalysis Degradation of Methylene Blue of TiO2 Nanotube Array Films Annealed in Oxygen Atmospheres

Well-aligned and uniform titanium dioxide nanotube arrays were fabricated in situ on titanium substrate by electrochemical anodic oxidation. SEM images indicate that the TiO2 nanotubes are well organized into high-density uniform arrays,with diameter ranging in size from 70 to 100 nm. The XRD patterns show that the sample fabricated by anodic oxidation is amorphous without being annealed. As the 500 degrees C annealed sample crystallized in the anatase phase, which is in good photocatalytic activity. In quartz glass reactor, the photoelectrocatalytic degradation of MB in aqueous solutions as well as the effect factors and then to 0.1 mol/L NaCl as the electrolyte, under with in oxygen atmospheres annealed the applied bias is 0.5 V and has a pH = 3.25, light intensity is 1 000 microW/cm2 and the surface area of nano-tube array film conditions, will help to improve the TiO2 nanotubes array film photoelectrocatalysis degradation of MB degradation efficiency is 99.56%. The results of EIS analyses revealed that the surface reaction step was the only rate limiting step either for the photoelectrocatalytic process. The extra bias potential could decrease the values of the electron-transfer resistance and increase the separation efficiency of photogenerated electron-hole pairs.