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 Tc 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.