In Situ Construction and Composition Manipulation of PbBiO2Br/Metal Halide Perovskite Heterojunction for Promoting Interfacial Charge Transfer and Photocatalytic Activity

Abstract

In situ construction of metal halide perovskites (MHPs) based heterojunction via atom cosharing has been regarded as an effective strategy to improve the photocatalytic activities, due to the establishment of high-quality interfaces for fast charge transfer and separation. Here, the potential of functional bimetallic selftemplate on the composition and structure manipulation thus the photoelectric properties of atom-cosharing MHPs based heterojunction was illustrated. We employed Sillén-structured bimetallic oxyhalide PbBiO2Br nanosheets as the self-template to in situ epitaxially grow Pb, Bi-based or mixed MHPs nanocrystals via acid etching process. It was revealed that the two "B site" metal of Pb2+ and Bi3+ enabled the in situ growth of Bi-doped CsPbBr3 (Bi-CsPbBr3), CsPb2Br5, or Cs3Bi2Br9 nanocrystals on the surface of PbBiO2Br nanosheets, which can be facilely controlled by HBr dosage. Therefore, both the light absorption and the interfacial charge separation of heterojunction can be facilely tuned at the same time, which contributes to manipulation of the corresponding photocatalytic performance. The optimized PbBiO2Br/Bi-CsPbBr3 heterojunction exhibited a total CO and CH4 yield of 38.44 μmol g−1 in 3 h when used as the photocatalyst for CO2 reduction, which was 14.3-fold of that of single PbBiO2Br. Further surface modification by ZIF-67 can contribute to enhanced charge separation and CO2 uptake of heterojunction, leading to improved total electron consumption rate of 45.72 μmol g-1 h-1 and photocatalytic stability. This work provides a simple and effective method for the in situ synthesis of high-quality perovskite heterojunctions, which would be easily extended to other atom-cosharing heterojunction.