Raspberry-like Cu2O/BiOBr S-scheme heterojunction photocatalyst for selective CO2 photoreduction to CO

Developing efficient and stable photocatalysts for CO2 reduction is crucial for mitigating greenhouse gas emissions and addressing energy challenges. However, low photogenerated carriers separation efficiency and poor photocatalyst stability hinder their practical applications. In this work, a raspberry-like Cu2O/BiOBr (COB) Sscheme heterojunction photocatalyst is successfully synthesized via a hydrothermal method. Structural characterizations reveal that BiOBr uniformly encapsulates Cu2O, forming a tightly bonded interface conducive to charge transfer. Band structure analysis combined with density functional theory (DFT) calculations indicated that an internal electric field (IEF) is generated at the Cu2O/BiOBr interface, establishing an S-scheme charge transfer pathway. This configuration not only enhances the separation of photogenerated carriers but also significantly improves the photostability of Cu2O. As a result, the optimized COB-5 photocatalyst exhibits excellent CO2 photoreduction performance with a CO production rate of 47.0 mu mol center dot g- 1 center dot h- 1, along with superior cycling stability. Furthermore, in-situ infrared spectroscopy and Gibbs free energy calculations revealed that COB-5 effectively lowers the energy barrier for the formation of the key intermediate COOH*, facilitating the selective generation of CO. This study provides a promising strategy for the rational design of high-performance photocatalysts for efficient and stable CO2 reduction.