Influence of ferroelectric dipole on the photocatalytic activity of heterostructured BaTiO₃/a-Fe₂O₃

Using BaTiO₃ as a model ferroelectric material we investigated the influence of the ferroelectric dipole on the photocatalytic activity of a heterogeneous BaTiO₃/α-Fe₂O₃ photocatalyst. Two distinct BaTiO₃ samples were used: BTO and BTO-A. The latter consists more ferroelectric tetragonal phase and thus stronger ferroelectricity. It was found that under identical experimental conditions, the photodecolourisation rate of a target dye using BTO-A/α-Fe₂O₃ under visible light was 1.3 times that of BTO/α-Fe₂O₃. Photoelectrochemical and photoluminescence analysis confirmed a more effective charge carrier separation in BTO-A/α-Fe₂O₃. Considering solely the photoexcitation of α-Fe₂O₃ in the composite photocatalysts under visible light and the similar microstructures of the two catalysts, we propose that the enhanced decolourisation rate when using BTO-A/α-Fe₂O₃ is due to the improved charge carrier separation and extended charge carrier lifetime arising from an interaction between the ferroelectric dipole and the carriers in α-Fe₂O₃. Our results demonstrate a new process to use a ferroelectric dipole to manipulate the charge carrier transport, overcome recombination, and extend the charge carrier lifetime of the surface material in a heterogeneous catalyst system.