Controllable Reconstruction of β-Bi₂O₃/Bi₂O₂CO₃ Composite for Highly Efficient and Durable Electrochemical CO₂ Conversion

The uncontrollable electrochemical reduction reconstruction, leading to the destruction of well-defined structure and subsequent low durability, is the main obstacle to the catalytic performance of Bi-based composites toward electrochemical CO₂ reduction reaction (eCO₂RR). Herein, we address this issue through construction of a novel β-Bi₂O₃/Bi₂O₂CO₃ composite, which can resist the reduction reconstruction of Bi-based materials to metallic Bi during the eCO₂RR process by modulating a more alkaline microenvironment that facilitates the formation of new Bi-O bonds. The synergistic interactions and directional electron transfer between the β-Bi₂O₃ and Bi₂O₂CO₃ components, together with the stable composite structure, result in its superior activity and selectivity for formate production with high faradaic efficiencies (FEs) over 94% from -0.7 to -1.1 V, and remarkable durability with maintenance of 80% FE after continuous electrocatalysis of 720 h. This work sheds new light on designing advanced high-performance nanomaterials toward eCO₂RR and other practical applications.