Synergy of TiO2/Na0.23TiO2 Heterojunction for Enhanced Photocatalysis

TiO2/Na0.23TiO2 composite photocatalyst is prepared by a simple hydrothermal method. Na0.23TiO2 appears at the alkali concentration of 1.2m, 320 degrees C, and 80min. Different morphologies are obtained under different experimental conditionsnamely, nanosheets, nanowire, and nanorod. The photocatalytic activity of TiO2/Na0.23TiO2 composites is superior to the raw anatase titanium dioxide (TiO2) for the degradation of methylene blue under UV-visible light irradiation. The best photocatalytic performance is achieved in a composite prepared at an alkali concentration of 1.5m. The photogenerated charge separation is a main factor in enhancing the activity of semiconductor-based photocatalysts. The calculated band gap of Na0.23TiO2 is about 2.904eV. The Fermi level lies in the conduction band in Na0.23TiO2 while it is near the valence band in anatase TiO2. Then, a heterojunction is formed and is helpful for the photogenerated electron-hole pairs separation, resulting in an enhanced photocatalysis.