CuSn bimetallic aerogel supported by B, N co-doped graphene oxide for selective and durable electrochemical reduction of CO2 to formate

CO 2 electroreduction (CO 2 RR) to formate is an attractive route for carbon utilization, yet the field continues to pursue catalysts that can achieve high selectivity, high current density, and long-term stability. Here we report a CuSn bimetallic aerogel supported on boron and nitrogen co-doped graphene oxide (CuSn/BNGO), which creates a Cu 6 Sn 5 -based CuSn/BN interface for formate production. The porous aerogel structure provides accessible active sites, while the BNGO support improves catalyst dispersion and surface area. Characterizations and electrochemical results indicate that B and N co-doping introduces a defect-rich carbon support, strengthens CuSn–support interaction, and facilitates charge transfer, thereby supporting selective formate production. In an H-cell, CuSn/BNGO reaches a peak FE formate of 87.5% at −1.1 V vs. RHE and sustains FE formate above 80% for 30 h and above 70% for 50 h. In a flow cell, CuSn/BNGO delivers 92.8% FE formate at a stable formate partial current density of 220 mA/cm 2 at −1.1 V vs. RHE, maintaining FE formate above 80% over 8 h. These results show that coupling a CuSn aerogel with BNGO is an effective strategy to increase active site exposure and charge transfer for selective CO 2 RR to formate conversion.