Multilayer Coaxial TiO2/BaTiO3/WO3 Nanorod Arrays with Enhanced Photoelectrochemical Properties under the Ferroelectric Polarization Effect

The introduction of ferroelectrics with spontaneous polarization into photocatalysts can inhibit the recombination of the photoinduced carriers. Ferroelectric photocatalysis provides a promising avenue for pollutant elimination using solar energy. In this work, multilayer coaxial TiO 2 /BaTiO 3 /WO 3 nanorod arrays were rationally designed and prepared by introducing the BaTiO 3 nanolayer between TiO 2 nanorods and outermost WO 3 films using in situ reaction on TiO 2 nanorods combined with sol–gel and dip coating methods. The TiO 2 /BaTiO 3 /WO 3 nanorods have an average length of 505 nm and an average diameter of 75 nm. The transient photocurrent density of TiO 2 /BaTiO 3 /WO 3 nanorod arrays is 2.3 times higher than that of TiO 2 /WO 3 . After positive poling at 3 V, the transient photocurrent density of TiO 2 /BaTiO 3 /WO 3 increases to 3.1 times the initial value. In addition, the superior degradation efficiency of MB under TiO 2 /BaTiO 3 /WO 3 nanorod arrays after positive poling reaches 92.3% within 2 h. The improved photoelectrochemical performance is due to the spontaneous polarization of BaTiO 3, which can effectively separate the photogenerated electron–hole pairs and accelerate their transfer, thus achieving good photocatalytic activity. This study provides a promising strategy for designing novel ferroelectric photocatalysts with improved performance.