In-situ regeneration of Bi0 active site to renew surface activation for long-term stable and efficient CO2-to-formate electrosynthesis

CO 2 -to-formate electrosynthesis with high selectivity and stability has been a long-sought objective. Unfortunately, most catalysts undergo structural and valence state changes due to surface oxidation during operation or storage, resulting in decreased catalytic performance. Herein, we report a efficient and stable BiIn@Cu-foam electrode through the in-situ regeneration of Bi 0 active sites to renew the surface activation. The electronic structure of Bi site can be regulated by introducing In, thereby enhancing the adsorption strength of *OCHO. The optimized electrode exhibits over 90% FE formate at a wide potential window (−0.9–−2.2 V), and formation rate for 3.15 mM cm −1 h −1 . Especially, the electrode can maintain the high performance at continuously electrolysis for more than 300 h, or for more than 50 cycles, even repeated operation and storage for more than 2 years. This work provides a promising candidate and new insight to construct industrially viable stable Bi-based catalyst for formate electrosynthesis.