Piezo-photocatalytic Effect on Oxidative Decomposition of Organic Dye Using Spin-coated and Sputter-deposited TiO₂/BaTiO₃ Films

This study proposes a TiO2/BaTiO3 heterojunction piezophotocatalytic films on a Ti substrate to enhance photocatalytic reactions by reactive carrier accumulation using piezoelectric polarization. Photocatalytic oxidation degrees were compared between the proposed TiO2/BaTiO3 piezophotocatalyst and a conventional TiO2 photocatalyst, when the combination of light illumination (wavelength: 370 nm) and ultrasonic vibration were applied. The reactivity of piezophotocatalyst was characterized by measuring color bleaching of methylene blue dye. When piezophotocatalyst and conventional photocatalyst were exposed to UV illumination with ultrasonic vibration at 45 kHz, an 11% higher optical transmission through methylene blue aqueous solution was observed one hour after the start of UV irradiation onto piezophotocatalyst. Although solution-processed and sputter-deposited TiO2/BaTiO3 films exhibited similar photocatalytic color bleaching performances under the light illumination and vibration conditions for maximum performance, the vibration frequency dependency was observed. BaTiO3 coated with different particle products were also comparatively characterized.