Stability and photocatalytic performance enhancement of sodium-doped CsPbBr₃/Cs₄PbBr₆ nanocomposites for dye wastewater degradation

Abstract

The extremely poor stability of lead halide perovskites has always been a challenge. In this paper, CsPbBr3 nanocrystals, CsPbBr3/Cs4PbBr6 nanocomposites and Na-CsPbBr3/Cs4PbBr6 nanocomposites were prepared by thermal injection and ligand-assisted reprecipitation method. The photocatalytic effect and stability of CsPbBr3 in aqueous systems were significantly improved by sodium ions doping and complexation with Cs4PbBr6. The results showed that the photocatalytic degradation rate of 5% Na-CsPbBr3 for Sudan red (III) was 57.8% within 180 min, while that of pure CsPbBr3 was only 14.47%. In the CsPbBr3/Cs4PbBr6 nanocomposites, Na-CsPbBr3/Cs4PbBr6 nanocomposites photocatalyzed nearly 94% of Sudan red (III) in 120 min, while CsPbBr3/Cs4PbBr6 photocatalyzed only 56% of organic dyes in the same time. Cs4PbBr6 can passivate CsPbBr3 in situ to enhance the stability of the perovskite material. In the four cyclic degradation experimental tests in aqueous systems, the nanocomposites maintained good stability performance. This study provides a new way to improve the catalytic performance and stability of perovskite materials.