An innovative S-scheme β-Bi2O3/BaTiO3 heterojunction nanocomposite with enhanced stability and photocatalytic performance

Abstract

S-scheme heterojunctions can effectively separate photogenerated electrons and holes while retaining high redox capacity. Therefore, the construction of S-scheme heterojunction composites to improve photocatalytic activity has attracted attention from the scientific community. In this study, BT was used as the external crystal nucleus to stabilize the β-BO phase, and a β-Bi₂O₃/BaTiO₃ (β-BO/BT) nanocomposite was prepared by a simple and green ultrasonic deposition–calcination method. The formation mechanism of the β-BO/BT nanocomposite has been successfully revealed. The photocatalytic performance of the β-BO/BT nanocomposite was significantly enhanced, mainly due to the effective charge separation and high redox capabilities of the S-scheme heterojunction mechanism, as well as the enhanced absorption of visible light. The photocatalytic rate constant reached 0.04642 min⁻¹, which was 24 and 9 times higher than those of pure BT and BO, respectively. Furthermore, the photodegradation efficiency of RhB by the β-BO/BT nanocomposite remained above 95% after five cycles. These results demonstrate that the β-BO/BT nanocomposite is an economical, stable, and highly efficient photocatalyst, and it has strong practical application potential in the removal of pollutants from wastewater. Finally, based on the analysis results of liquid chromatography–mass spectrometry and gas chromatography–mass spectrometry, the pathways for the photodegradation of RhB by the β-BO/BT nanocomposite were proposed. This study presents a novel approach to the rational design of heterojunction photocatalysts through phase and interface engineering.