Uniformity, Structure, and Photocatalytic Activity of TiO_2 Films Deposited by Atmospheric-Pressure Linear Cold Plasma

摘要

Atmospheric-pressure (AP) linear cold plasma CVD is employed to deposit TiO_2 photocatalytic films uniformly on a moving substrate. The in-plane and in-depth uniformities of the as-deposited TiO_2 films are investigated by scanning electron microscopy (SEM) and UV-vis spectroscopy. The chemical binding states and compositions of the as-deposited TiO_2 films are characterized by X-ray photoelectron spectroscopy (XPS). Raman, X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectra prove the structures of the as-deposited and calcined TiO_2 films are mainly hydro-oxygenated amorphous (a-TiO_x:OH), and exclusively anatase, respectively. The photocatalytic activity of the as-deposited and calcined TiO_2 films is evaluated in a continuous flow reactor for HCHOremoval with simulated air. The activity of the as-deposited TiO_2 films increases with film thickness, leveling off at about 780 nm. The activity of the as-deposited TiO_2 film is lower than that of the calcined one.