Coupling CO2 reduction with CH3OH oxidation for efficient electrosynthesis of formate on hierarchical bifunctional CuSn alloy

It is a promising avenue for electrosynthesis of a single chemical at both cathode and anode, via concurrent CO2 reduction reaction (CO2RR) coupled with energy-efficient and value-added organic oxidation reaction, while present electrocatalysts suffer low production rate. Herein, for the first time, we report a hierarchical bifunctional CuSn alloy electrocatalyst for efficient production of a single formate via simultaneous cathodic CO2RR and anodic methanol oxidation reaction (MOR), achieving a record-high formate production rate of 3313 μmol h–1 cm–2, with nearly 100% formate selectivity. Moreover, coupling CO2RR with MOR requires an electricity input of only 2.61 kWh kgformate–1, in contrast to the 4.46 kWh kgformate–1 required for CO2RR coupled with conventional oxygen evolution reaction. DFT calculation results reveal that the calculated limiting potential for formate production is lower than those for CO and H2 production on CuSn alloy, leading to the high selectivity for formate production.