MOF derived bimetallic CuBi catalysts with ultra-wide potential window for high-efficient electrochemical reduction of CO2 to formate

The Faradaic efficiency of formate and the mechanism of CO2 reduction to formate on the CuBi75 electrode. [Display omitted] •The rod-like bimetallic CuBi catalysts were successfully synthesized through carbonization and oxidation of MOF precursors.•The Bi2CuO4 was found as new phase to change the adsorption pathway and capacity of CO2.•The catalysts showed the valid potential window to 900 mV and boosted the FEformate to 100 % at −0.77 V vs RHE.•In-situ FT-IR and DFT calculation testified that HCOO* intermediate is preferable on Cu-Bi active sites. Bimetallic electrocatalysts have been proved to be an effective approach to improve the activity and selectivity of electrochemical reduction reaction of CO2 (CO2RR) to formate. However, the activity of catalyst and selectivity of formate are still unsatisfactory. Herein, the rod-like CuBi bimetallic catalysts were synthesized by carbonization and oxidation of CuBi-MOF precursors. Owing to the formation of Bi2CuO4 in the interface of catalyst, the activity and selectivity of the bimetallic CuBi catalysts were greatly enhanced, showing an allured high FEformate of 100 % at −0.77 V (vs. RHE), ultra wide potential window of 900 mV, and excellent durability in H-cell. The in-situ FT-IR and DFT calculation demonstrated that the HCOO* pathway was dominant. Bi2CuO4 can boost the CO2 molecules adsorption capacity and enhance the charge transfer capacity, which benefit its activity and formate selectivity for CO2RR. This work offers insights in improving the catalytic performance of bimetallic catalysts for CO2RR.