Non-thermal Effect of Atmospheric-Pressure RF Cold Plasma on Photocatalytic Activity of As-deposited TiO2 Film

TiO2 film is deposited by atmospheric-pressure (AP), radio-frequency (RF), dielectric barrier discharge (DBD) plasma at a low power using titanium tetraisopropoxide (TTIP) and O2 as the precursors. The morphology, optical properties, and crystalline structure of the as-deposited TiO2 film are investigated by using scanning electron microscopy (SEM), atomic force microscopy (AFM), ultraviolet-visible (UV-vis) absorption spectroscopy, and Raman spectroscopy. The as-deposited TiO2 film show high photocatalytic activity in complete oxidation of HCHO to CO2 and degradation of stearic acid. The gas temperature in the RF-DBD plasma is estimated to be at about 500?K by the rotational temperature via optical emission spectroscopy (OES). The experimental results of amorphous TiO2 film treated by the RF-DBD plasma further exclude the likelihood of thermal effects derived from the plasma on crystallization of TiO2 film. It is confirmed that the non-thermal effect of the RF-DBD plasma on the high photocatalytic activity of the as-deposited TiO2 film does exist.