Improving the charge properties of the WO₃ photoanode using a BiFeO₃ ferroelectric nanolayer

Tungstic oxide (WO₃) is a promising visible-light-responsive photoanode material, but it has poor charge transport and collection properties. In this study, a WO₃/BiFeO₃ core/shell photoanode (WO₃/BFO) with enhanced photoelectrochemical (PEC) performance was successfully prepared using a facile spin-coating method. The optimal WO₃/BFO shows an excellently enhanced and stable photocurrent density of ∼2.83 mA cm^-2 at 0.6 V vs. Ag/AgCl, which is ∼244% more than WO₃ under AM 1.5 illumination. The results of Mott-Schottky tests, intensity modulated photoelectrochemical spectroscopy and transient photocurrent decay indicated that the BFO ferroelectric nanolayer significantly enhances the charge density of the WO₃/BFO, and improves its charge transport and separation property and charge lifetime, which could be the reason for the enhanced PEC activity of WO₃/BFO.