Synergetic efficiency: in situ growth of a novel 2D/2D chemically bonded Bi2O3/Cs3Bi2Br9 S-scheme heterostructure for improved photocatalytic performance and stability†

Abstract

Adverse reactions caused by waterborne contaminants constitute a major hazard to the environment. Controlling the pollutants released into aquatic systems through water degradation has been one of the major concerns of recent research. Bismuth-based perovskites have exhibited outstanding properties in the field of photocatalysis. Nonetheless, many proposed bismuth-based perovskites still suffer from stability problems. The present study investigated a unique bismuth-based metal-co-sharing composite of 2D Bi₂O₃/Cs₃Bi₂Br₉ nanosheet perovskite synthesized via a modified anti-solvent reprecipitation method. Several samples were prepared using different ratios of Bi₂O₃ and Cs₃Bi₂Br₉. The optimal composite sample was found to be BO/CBB 28%, where 2D stacked nanosheets of Cs₃Bi₂Br₉ showed remarkable interaction with Bi₂O₃ due to its optimal Bi co-sharing, as displayed in the FE-SEM and HRTEM images. However, further increasing the percentage led to greater agglomeration, hindering the photocatalytic degradation efficiency. The average size and optical band gap energy of the optimal sample were 42.5 nm and 2.46 eV, respectively. The photocatalytic degradation of MB using the optimal sample reached ∼92% within 60 min with a catalyst dosage of 10 mg L⁻¹. With an increase in catalyst concentration to 40 mg L⁻¹, MB removal reached almost ∼96% within 60 min under visible light owing to the enhanced stability, facilitating efficient charge separation. This paper presents an improved composite with optimal ratios of 2D Bi₂O₃/Cs₃Bi₂Br₉ nanosheets that demonstrated good stability and enhanced photocatalytic performance in comparison with pure Bi₂O₃ and Cs₃Bi₂Br₉. This study also sheds light on the significance of metal co-sharing and the pivotal role it plays in enhancing the S-scheme charge transfer and the internal electric field between the two components.