Effect of ferroelectric Ba0.8Sr0.2TiO3 on the charge carrier separation of BiOBr at different temperature

The internal electric field formed by spontaneous polarization of ferroelectrics, as a potential driving force to improve the separation efficiency of photo-generated charge carriers, has become one of the research hotspots in photocatalytic field. Here, a series of Ba1-xSrxTiO3 (x = 0.1, 0.15, 0.2, 0.25) nanoparticles with different Curie temperature (TC) synthesized by hydrothermal method were combined with BiOBr to prepare the (1-y)BiOBr/yBa0.8Sr0.2TiO3 composite photocatalyts. The photocatalytic performance of ferroelectric Ba1-xSrxTiO3 (≤TC) is superior to that of paraelectric Ba1-xSrxTiO3 (≥TC). Polarization-electric field hysteresis loops (P-E loops), piezoresponse force microscopy (PFM), electron paramagnetic resonance (EPR) results and photocatalytic degradation experiments at different temperature indicate that the internal electric field of ferroelectric Ba0.8Sr0.2TiO3 can effectively boost charge carrier separation and significantly enhance the photocatalytic performance of BiOBr/Ba0.8Sr0.2TiO3. The photocatalytic degradation efficiency over ferroelectric 0.8BiOBr/0.2Ba0.8Sr0.2TiO3 can be reached to be more than 97% at 35 °C, which is almost 1.5 times and 1.3 times higher than that of individual Ba0.8Sr0.2TiO3 and BiOBr at 55 °C, respectively. This work provides an experimental evidence and a theoretical guidance for the enhanced photocatalytic performance of ferroelectrics and new ideas for the research and development of high efficiency ferroelectric photocatalytic materials.