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 SO4 2– 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.