Novel Fe2O3/PZT Nanorods for Ferroelectric Polarization-Enhanced Photoelectrochemical Water Splitting

As an ideal photocatalyst in the photoelectrochemical (PEC) water oxidation area, hematite (α-Fe2O3) has received much attention from scientists on account of its favorable band gap and excellent stability in alkaline media. However, the practical photocurrent yield of α-Fe2O3 is much less than the theoretical value because of the high charge recombination and the low charge transport. Herein, a novel ferroelectric Fe2O3/Pb(Zr0.2Ti0.8)O3 photoanode (Fe2O3/PZT) was fabricated by simple spin coating along with a one-step calcination method for the first time. As expected, the Fe2O3/PZT photoanode showed a significantly greater photocurrent (by ∼10 times) and the initial potential (by ∼100 mV) was more negative than that of the pure Fe2O3 nanorod photoanode, which was attributed to the depletion layer width increase and the upward band bending in Fe2O3 induced by ferroelectric polarization of PZT, leading to efficient charge separation and injection. Moreover, the photoelectrochemical performance of the Fe2O3/PZT nanorod photoanode could be regulated by simply changing the polarization direction of PZT. In addition, the Fe2O3/PZT nanorod photoanode showed not only a fast and repetitive light response but also long-term stability for 96 h. This research presents a novel route to enhance the efficiency of charge separation and affords theoretical guidance for preparing the high-efficiency PEC photoanodes and the switchable control of the photoelectrochemical response.