Ex situ and in situ characterization studies of spin-coated TiO_2 film electrodes for the electrochemical ozone production process

摘要

An electrode composed of silicon/titanium oxide/platinum/titanium dioxide (Si/TiO_x/Pt/TiO_2) was fabricated by spin-coating TiO_2 multilayers on a Si/TiO_x/Pt substrate and was used in electrochemical ozone production (EOP). EOP was realized when the Si/TiO_x/Pt substrate was completely covered with the TiO_2 film and a current efficiency of 7% was achieved at a low current density of 26.7 mA cm~(-2) in 0.01 M HClO_4 at 15℃. The TiO_2 film was found to be of an anatase-type TiO_2 and that to comprise aperture structures from the X-ray diffraction (XRD) and transmission electron microscopy (TEM) observations. Moreover, the fabricated TiO_2 film was found to be an n-type semiconductor by photoelectrochemical measurements. The high efficiency at a low current density of EOP on the TiO_2 n-type semiconductor was explained to result from the electron transfer through the TiO_2/HClO_4 interface as tunneling current. When the tunneling current passes through a depletion layer of TiO_2, the electrode potential is necessarily high enough to facilitate EOP.