S-Scheme Heterojunction Efficient Extraction of Hot Carriers in CsPbBr3/Bi4O5I2 for Enhanced Photocatalytic H2 Evolution and CO2 Reduction

This study investigates the photocatalytic capabilities of an S-scheme heterojunction formed by CsPbBr₃ and Bi₄O₅I₂ for H₂ evolution and CO₂ reduction. The heterojunction is designed to enhance the extraction of hot carriers and charge separation through interface engineering and an internal electric field. The initial T_c at higher pumping intensities indicates that CsPbBr₃ carriers injected into Bi₄O₅I₂ at higher energies and temperatures cooled from 1800 to 800 K within 200 fs after photoexcitation. Compared with CsPbBr₃, CsPbBr₃/Bi₄O₅I₂ showed substantial improvement in photocatalytic H₂ production from 59.08 to 1050.93 μmol h^–1 g^–1. Furthermore, the S-scheme CsPbBr₃/Bi₄O₅I₂ heterojunction displays outstanding photocatalytic CO₂ to CO performance, compared to pure CsPbBr₃, from 2.84 to 83.6 μmol h^–1 g^–1. These findings contribute to the understanding and development of S-scheme heterojunction extraction of hot carriers in perovskite materials for photocatalytic applications.