Optical and Photocatalytic Properties of Cu-Cu2O/TiO2 Two-Layer Nanocomposite Films on Si Substrates

摘要:

通过磁控溅射法在TiO2薄膜上生长Cu-Cu2O复合层，从而制备新型Cu-Cu2O/TiO2双层纳米复合薄膜。并采用X射线衍射（XRD），扫描电子显微镜（SEM），荧光光谱（PL），X射线光电子能谱（XPS）和紫外可见漫反射光谱（DRS）等方法对膜的结构，形态和光学性能进行了研究。X射线衍射谱表明，Cu-Cu2O混合物层和Cu2O层都没有影响TiO2的结晶相。XPS结果表明，Cu的存在抑制了Cu2O表面在空气中的氧化。SEM分析表明，结晶良好的Cu-Cu2O混合物微小纳米颗粒均匀分散于TiO2表面。由于紫外可见漫反射光谱的Cu-Cu2O/TiO2复合薄膜的吸收边发生红移。PL光谱证实了在Cu的存在下，激发电子和空穴的复合率降低。光催化实验表明，与纯Cu2O/TiO2相比，所制备的Cu-Cu2O/TiO2-8显示出更高的光生载流子效率，其光催化性能也显著提高。此外，还对Cu-Cu2O/TiO2-8光催化活性增强的原因进行了讨论

Abstract:

This paper introduced a process to prepare novel Cu-Cu2O/TiO2 two-layer nanocomposite films with Cu-Cu2O mixture layers grown on TiO2 films prepared by a magnetron sputtering method. The structure, the morphology and optical properties of the films were investigated by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), fluorescence spectroscopy (PL), X-ray photoelectron spectroscopy (XPS) and UV-vis diffuse reflectance spectroscopy (DRS). XRD patterns indicate that the Cu-Cu2O mixture layer does not change the crystalline phase of TiO2. XPS results show that the presence of Cu restrains the oxidation of Cu2O surface for Cu-Cu2O/TiO2 layer. SEM analysis reveals that the well crystallized Cu-Cu2O mixture nanoparticles are dispersed uniformly on the surface of TiO2. Owing to UV-vis diffuse reflectance spectroscopy, an red shift of the extended absorption edge of Cu-Cu2O/TiO2 takes place. PL spectra confirm the presence of Cu which reduces the recombination rate of exited electron-hole. Photocatalytic experiments demonstrate that compared with pure Cu2O/TiO2, the as-prepared Cu-Cu2O/TiO2-8 shows greater efficiency in photogenerated carriers and a significantly improved photocatalytic performance. In addition the reason for improvement in photocatalytic activity of the Cu-Cu2O/TiO2-8 films was also discussed