高催化活性银氮共掺纳米TiO₂薄膜的性能研究

Performation of Nano-TiO₂ Film with High Photocatalytic Activity

摘要: 为了有效降解环境污染物，通过溶胶凝胶法在玻璃基底上制备了(Ag,N)-TiO₂薄膜。采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、紫外可见分光光谱仪(UV-vis)对薄膜的晶相结构、表面形貌和光学性能进行了分析。通过可见光下对亚甲基蓝溶液的光催化降解实验研究了薄膜的光催化活性。结果表明：(Ag,N)-TiO₂薄膜的结晶度很高，TiO₂以锐钛矿的形式存在，表面由形状规则的球形颗粒组成，平均晶粒尺寸约为20 nm，并且(Ag,N)-TiO₂薄膜与玻璃基底结合紧密，二者之间无空隙出现，薄膜厚度约为150 nm；(Ag,N)-TiO₂薄膜的光谱响应范围不仅扩展到了可见光区，而且对可见光的吸收强度较高；(Ag,N)-TiO₂薄膜的可见光光催化活性优于单一Ag掺杂、单一N掺杂以及纯TiO₂薄膜的活性。300 min光照后，亚甲基蓝溶液的降解率接近70%，这是由于贵金属Ag可降低光生电子-空穴对的复合率，非金属N能有效拓宽薄膜的光谱响应范围，在二者的共同作用下，薄膜的光催化活性得到了提高。

Abstract: In order to degrade environmental pollutants effectively, (Ag,N)-TiO₂ film was prepared on glass substrate by a sol-gel method. The crystal structure, surface morphology and optical properties of the films were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-vis spectrometry (UV-vis). The photocatalytic activity of the film was studied by photocatalytic degradation of methylene blue solution under visible light and the results showed that the films with high crystallinity were composed of anatase phase. The film surface is composed of regular spherical particles with an average grain size of about 20 nm; the film is 150 nm thick and tightly bonded to the glass substrate with no gap between them. The spectral response range of (Ag,N)-TiO₂ film not only extends to the visible region, but also has a higher absorption intensity for visible light. The visible light photocatalytic activity of (Ag,N)-TiO₂ film is better than that of single Ag doping or N doping and pure TiO₂ film. After 300 min illumination under visible light, the degradation rate of methylene blue solution is close to 70%. The reason for this is that noble metal Ag can reduce the recombination rate of photogenerated electron-hole pairs while non-metal N broadens the spectral response range of the film effectively, which improve the photocatalytic activity greatly.