A dual optimization approach for photo-electric catalysis: Heterojunction of BiOBr/Ba0.7Sr0.3TiO3 system construction and ferroelectric polarization

Abstract

The spontaneous polarization of ferroelectrics is used to promote the separation of photogenerated electrons and holes, showing the great potential of solar-driven photo-electric catalysis. However, the rapid recombination of photogenerated electrons and holes seriously restricts the photo-electric catalysis efficiency. In this study, Ba0.7Sr0.3TiO3 nanoparticles combined with BiOBr nanosheets are synthesized by hydrothermal method to prepare BiOBr/Ba0.7Sr0.3TiO3 composite photoelectrodes. Under different Curie temperature(Tc) conditions and visible light irradiation, the photocurrent density of ferroelectric Ba0.7Sr0.3TiO3 (≤Tc) (0.54 mA∙cm−2) is superior to that of cis-electric Ba0.7Sr0.3TiO3 (≥Tc) (0.46 mA∙cm−2).The potential difference at the interface of BiOBr/Ba0.7Sr0.3TiO3 can effectively promote the separation of photogenerated carriers, while the internal polarization electric field of ferroelectric Ba0.7Sr0.3TiO3 further promotes the separation and transfer of photogenerated electrons and holes in the photoelectrodes, allowing more charges to be injected into the heterojunction interface to participate in the surface redox reaction, which significantly improves the photo-electric catalysis performance of BiOBr/Ba0.7Sr0.3TiO3. We believe that this work may open up new avenues for the research and development of highly efficient polarized ferroelectric material photoelectrodes for photo-electric catalysis.