Deposition of photocatalytic anatase titanium dioxide films by atmospheric dielectric barrier discharge

In this study, TiO2 films are easily deposited in a single-step process from titanium tetraisopropoxide (TTIP) using a dielectric barrier discharge (DBD) device under atmospheric pressure at room temperature. The surface morphology of the as-deposited TiO2 films is observed by scanning electron microscopy (SEM). The as-deposited TiO2 films exhibit nanometer-sized particles with a lot of agglomerates. The cross section images indicate that the deposition rate of TiO2 films can reach about 70nm·min−1, which is much faster than that of conventional low pressure chemical vapor deposition (CVD) (typically <4nm·min−1). In order to confirm the structure composition and optical properties of the films, glancing incidence X-ray diffraction (GIXRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FTIR) are employed. The as-deposited TiO2 films are partly crystalline which show a good photocatalytic activity in the degradation of methylene blue under UV irradiation. After annealing at 673K, the TiO2 films are in the anatase phase and composed by homogeneous nanoparticles. The photocatalytic degradation rate of methylene blue of the TiO2 films after annealing (~0.6h−1) is almost 4 times higher than that of the as-deposited TiO2 films (~0.16h−1). The photocatalytic degradation rate of the TiO2 film after annealing is the same as the one of the commercial anatase TiO2 spin coated film when the error bar is taken into account. The TiO2 films show excellent photocatalytic stability during 3 recycling photocatalytic measurements.