CsPbBr₃ Nanocrystals Stabilized by Lead Oxysalts for Photocatalytic CO₂ Reduction

The undercoordinated Pb 2+ sites on a CsPbBr 3 surface would induce serious instability issue. Here we demonstrate a facile method to eliminate the undercoordinated Pb 2+ sites of CsPbBr 3 for photocatalytic CO 2 reduction. The SO 4 2– ions can bond with the surface Pb 2+ sites, thus forming a water-insoluble PbSO 4 . The surface PbSO 4 can effectively improve the water resistance and decrease the defects of CsPbBr 3 nanocrystals (NCs). The resultant CsPbBr 3 –SO 4 NCs exhibit an improved photocatalytic activity toward CO 2 reduction, which is about 8 times higher than that of the CsPbBr 3 NCs. This work highlights the importance of surface modification on improving the photoelectronic properties of perovskites.