Synthesis and SPEF-Induced Enhanced Photoelectrochemical Performance of the BaTiO3@α-Fe2O3 Ferroelectric Heterojunction

We have combined ferroelectric BaTiO3 nanostructures with α-Fe2O3 nanoparticles to prepare BaTiO3@α-Fe2O3 core@shell heterojunction photoelectrodes. The effects of α-Fe2O3 nanoparticle loadings on photoelectrochemical (PEC) water splitting performance of BaTiO3@α-Fe2O3 heterojunction photoelectrodes were studied. If one optimizes the loadings of α-Fe2O3 nanoparticles, the highest photocurrent density of BaTiO3@α-Fe2O3 heterojunction photoelectrode is 0.37 mA/cm2, which is 3.7 times higher than that of pure BaTiO3 nanostructures. The enhanced PEC performance of BaTiO3@α-Fe2O3 heterojunction photoelectrode is attributed to the effective charge transfer and separation. To reveal that the spontaneous polarization electric field (SPEF) effect is responsible for the enhanced charge separation and transfer, the PEC performances of ferroelectric and non-ferroelectric BTO@FO heterojunction photoelectrodes were studied. Our research provides direct evidence that the SPEF of BaTiO3 nanostructures promotes the efficient charge carrier separation, resulting in the significant enhancement for PEC performance. The suggested working mechanism of the charge separation and transfer in BTO@FO heterojunction photoelectrode is provided.