新型TiO2 NTs制备和结构控制及其硝基苯光催化性能研究

实验采用二次阳极氧化法制备高度有序的阵列式TiO2纳米管（TiO2 NTs），分别利用扫描电镜（SEM）、能谱仪（EDS）、X射线衍射仪（XRD）和紫外-可见漫反射光谱仪（UV-vis DRS）对制得的TiO2 NTs的微观形貌及光响应范围进行表征与测试。SEM显示经过二次阳极氧化处理后，TiO2 NTs的形貌发生较大改变，呈现出良好的阵列效果。UV-vis DRS光谱显示光响应范围明显发生红移。将硝基苯作为目标有机污染物，利用TiO2 NTs作为光催化剂对其进行光催化降解。结果显示，TiO2 NTs能有效降解废水中的硝基苯，并且经二次阳极氧化制得的阵列式TiO2纳米管（2-step TiO2 NTs）的光催化活性远远优于经一次氧化的TiO2纳米管（1-step TiO2 NTs），能显著提高对硝基苯的降解效率。推测活性增加的原因是经二次氧化形成的阵列式双层纳米管结构增大了催化剂的比表面积，同时增加光通道，使TiO2纳米管吸光范围显著增大，提升硝基苯的降解速率。

The preparation and structural control of novel hierarchical TiO2 nanotube arrays and photocatalytic performance study of nitrobenzene

The highly ordered TiO2 nanotube arrays (2-step TiO2 NTs) were prepared via a facile two-step anodization method. The micro morphology, crystal form, elemental composition and photoresponse were characterized by SEM, XRD and UV-vis DRS respectively. The images of SEM showed that the 2-step TiO2 NTs exhibited superior array effect. At the same time, the UV-vis DRS showed that the range of photoresponse shifted towards long wave obviously. Nitrobenzene was utilized to be a target organic pollutant to characterize the catalyst performance. The result showed that nitrobenzene could be degraded by the 2-step TiO2 NTs effectively, and the photocatalytic activity of 2-step TiO2 NTs was far better than the 1-step TiO2 NTs. The photocatalytic degradation efficiency of nitrobenzene was improved remarkably. The reason of the efficiency improvement was caused by the highly ordered structure of the 2-step TiO2 NTs which increased the specific surface area of the photocatalyst. Therefore, the optical channel was increased, photoabsorption region was broadened and the photo-quantum efficiency was improved.