Interfacial chemistry of CuBi2O4 in aqueous media: engineering strategies for energy and environmental applications

Abstract

Copper bismuthate (CuBi₂O₄) has emerged as a promising p-type semiconductor for solar energy conversion and environmental remediation due to its favorable band gap (1.5–1.8 eV) for visible light absorption and suitable band edge positions. However, its practical application is significantly hindered by inherent instability in aqueous electrolytes, leading to photocorrosion, and by poor charge transport properties, which cause low quantum yields. This review provides a comprehensive analysis of the surface and interface behaviors of CuBi₂O₄, including dissolution, electrochemical corrosion, and photoelectrochemical corrosion mechanisms. It critically examines various surface and interface engineering strategies—such as protective overlayers (e.g., TiO₂, MgO), co-catalyst integration (e.g., Pt, RuO_x), heterojunction formation (e.g., with CuO, ZnO), and doping (e.g., Fe, Ag)—aimed at mitigating degradation and enhancing performance in applications like water splitting, CO₂ reduction, and pollutant degradation. While these strategies have shown success in improving stability and efficiency, significant challenges remain in achieving long-term durability and bridging the gap between laboratory-scale results and practical, large-scale implementation. Future research directions should focus on advanced in situ characterization, computational modeling, development of novel protective materials, and scalable synthesis techniques to unlock the full potential of CuBi₂O₄.