Synthesis and characterization of copper ions surface-doped titanium dioxide nanotubes

Copper ions surface-doped titanium dioxide nanotubes were prepared via an assembly process based on the reactions between Cu(NH₂CH₂CH₂NH₂)₂(OH)₂ and hydroxide radicals on the surface of TiO₂ nanotubes, followed by the heat treatment in air at 723 K. The as-prepared samples were characterized with infrared spectroscopy (IR), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman spectroscopy, and fluorescence spectroscopy (FL). The photocatalytic activity of the copper ions surface-doped titanium dioxide nanotubes was investigated by photodegradation of Rhodamine B. The results showed that copper ions were successfully introduced onto the surface of TiO₂ nanotubes. And two kinds of copper species of Cu(I) and Cu(II) were found on TiO₂ surface. Copper ions act as electron trappers facilitating the separation of electrons and holes on the surface of TiO₂ nanotubes, which allows more efficiency for the photodegradation of Rhodamine B.