Au负载N掺杂TiO2纳米管阵列的制备及其性能

TiO₂ 纳米管阵列较大的禁带宽度是导致其光催化效率较低的重要原因,采用磁控溅射、阳极氧化以及气氛退火相结合的方法对 TNAs 改性后制备了 Au 负载 N 掺杂 TiO₂ 纳米管阵列(Au@ N-TNAs),然后以甲基橙为目标污染物, 进一步分析了 Au@ N-TNAs 在不同 Au 负载量时光降解效率的变化情况。 采用 SEM、XRD、TEM 和 X 射线光电子能谱 (XPS)等对 Au 和 N 在 Au@ N-TNAs 中的存在形式进行表征和分析,发现 Au 主要是负载在 TiO₂ 纳米管阵列上,而 N 元素则是以掺杂的方式进入 TiO₂ 纳米管阵列的晶格中。 此外,在光降解试验中发现通过 Au 负载与 N 掺杂相结合的方法对 TiO₂ 纳米管阵列进行复合改性后,TiO₂ 纳米管阵列的光催化效率得到显著提升,其中 20s-Au@ N-TNAs 具有最佳的光降解效率。 但 Ti-N 薄膜中间的 Au 层太厚时会影响阳极氧化过程中 TiO₂ 纳米管阵列的生长,而且过量的 Au 在退火处理时很难及时地扩散均匀,进而使得改性后的 TiO₂ 纳米管阵列(40s-Au@ N-TNAs)的光催化效率明显降低。

Preparation and Properties of Au-supported N-doped TiO2 Nanotube Arrays

The low photocatalytic efficiency of TiO₂ nanotube arrays is mainly due to its large band gap, in this paper, Au-supported N-doped TiO₂ nanotube arrays (Au@ N-TNAs) were prepared by modifying TNAs by a combination of magnetron sputtering, anodizing, and atmospheric annealing, then methyl orange was used as the target pollutant to analyse the photodegradation efficiency of Au@ N-TNAs under different Au loading. SEM, XRD, TEM, and X-ray photoelectron spectroscopy (XPS) were used to characterize the existence of Au and N in Au@ N-TNAs. According to the analysis, Au was mainly supported on TiO₂ nanotubes arrays, and N was doped into the lattice of TiO₂ nanotubes arrays. In addition, it was found that the composite modification of the TiO₂ nanotube arrays by a combination of Au loading and N doping in this photodegradation experiment, then the photocatalytic efficiency of the modified TiO₂ nanotube arrays were significantly improved, and 20s-Au@ N-TNAs had the best photodegradation efficiency. However, when the Au layer in the middle of the Ti-N thin film was too thick, it would affect the growth of TiO₂ nanotubes arrays during anodization, and the excessive Au was difficult to diffuse uniformly in time during the annealing treatment, there-by making the photocatalytic efficiency of the modified TiO₂ nanotube arrays (40s-Au@ N-TNAs) were significantly reduced.