CsPbBr3 Nanocrystals Stabilized by Lead Oxysalts for Photocatalytic CO2 Reduction

The undercoordinated Pb2+ sites on a CsPbBr3 surface would induce serious instability issue. Here we demonstrate a facile method to eliminate the undercoordinated Pb2+ sites of CsPbBr3 for photocatalytic CO2 reduction. The SO42- ions can bond with the surface Pb2+ sites, thus forming a water-insoluble PbSO4. The surface PbSO4 can effectively improve the water resistance and decrease the defects of CsPbBr3 nanocrystals (NCs). The resultant CsPbBr3-SO4 NCs exhibit an improved photocatalytic activity toward CO2 reduction, which is about 8 times higher than that of the CsPbBr3 NCs. This work highlights the importance of surface modification on improving the photoelectronic properties of perovskites.