阳极氧化TiO_2纳米管阵列的制备与表征

Preparation and characterization of anodic oxidation TiO_2 nanotube arrays

采用阳极氧化法,分别选用HF和NH4F两种电解质,对纯钛进行阳极氧化处理制备TiO_2纳米管阵列。选用扫描电子显微镜、透射电子显微镜、能谱及X-射线衍射对纳米管的形貌、化学成分和物相结构进行表征和分析。结果表明:在HF体系中,随着氧化时间的增加,纳米管整齐度增加,同时管径也增大,当氧化时间为20 min时,管内径约60 nm,壁厚约10 nm;而纯钛片厚度的变化对纳米管的形貌没有明显的影响。在NH_4F体系中,加热使纳米管的内径增加,壁厚变薄,内径达到130 nm,壁厚约7 nm,这是由于加热使氧化反应速率增加,加快了纳米管的形成速率。EDS检测的Ti和O的原子数的比例接近1∶2。XRD图谱表明,在450℃热处理后的纳米管的物相结构为锐钛矿,由此可见,阳极氧化制备的纳米管阵列为二氧化钛纳米管。

Anodic oxidation was used to fabricate TiO2 nanotube arrays in HF and NH4F systems on the surface of pure titanium plate. The microstructures of the samples were characterized by scanning electron microscope, Transmission electron microscope, X-ray diffractometry and energy dispersive spectrometer. The results show that the ordering and diameter of nanotube increase with oxidation time increase in HF system. When the oxidation time is 20 min, the diameter and wall thickness of nanotube are about 60 nm and 10 nm, respectively. In the process of anodic oxidation, heating causes the increasing of internal diameter and the de- creasing of wall thickness in NH4 F system. The internal diameter and wall thickness of nanotube are 130 nm and 15 nm, respectively. It is due to the increase of oxidation rate during heating. Then, it causes the incre- ment of nanotube grow rate. The number of Ti and O atoms was determined by EDS, and their ratio is close to 1 ： 2. Phase composition of nanotube after heating treatment at 450℃ is anatase. Therefore, the chemical composition of nanotube arrays prepared by anodic oxidation is titanium dioxide.