Porphyrin-prompted robust lead-free cesium bismuth bromide for efficiently photodegrading antibiotics pollutants in water

The lead-free halide perovskite represented by Cs3Bi2Br9 (CBB) has attracted intense attention as an environmentally friendly alternative for toxic lead halide perovskite (CsPbBr3). However, the limited light absorption and instability of Cs3Bi2Br9 hinder its practical application in photocatalysis. In this work, Cs3Bi2Br9 nanosheets was modified with bifunctional porphyrin (CBB-TCPP) displayed enhanced visible light absorption properties and promising water stability. The CBB-0.5TCPP shows a sharply improved photodegradation performance of 84 % in 60 min in water and demonstrating the outstanding cycling stability. Furthermore, photoelectrochemical tests suggested that the charge separation and transfer properties of the modified perovskite materials were significantly improved compared with the pristine CBB. The CBB-0.5TCPP exhibited an impressive photogenerated carrier separation efficiency of 90.74 %. This work innovatively proposes a new way to modify perovskite with double duty by boosting stability and optimizing light absorption properties. [Display omitted] •This work reports a strategy of constructing hydrostable Cs3Bi2Br9 with optimized light harvesting by TCPP modification.•Cs3Bi2Br9 modified TCPP (CBB-xTCPP) were synthesized from the self-assembly method with a 30-nm thickness.•CBB-0.5TCPP exhibited the best photocatalytic performance and degraded 84 % aqueous TC-HCl in 60 min.•The superior aqueous activity is related to the optimized protection and light utilization.•The main active radicals for the photodegradation are ·O2-, e-, and h+.