Built in electric field boosted photocatalytic performance in a ferroelectric layered material SrBi2Ta2O9 with oriented facets: Charge separation and mechanism insights

·A SrBi2Ta2O9 ferroelectric sample with exposed facet is synthesized.·SrBi2Ta2O9 with {001} facet is 138 times of the pristine one for CIP degradation.·Built-in electric field along polarization direction promotes charge separation.·The possible degradation pathways and intermediates toxicity are analyzed.