Interface optimization and process scale-up study of electrocatalytic reduction of CO2 to CO in acidic flow electrolyzers
The electrocatalytic carbon dioxide reduction reaction(eCO2RR)powered by renewable energy can convert CO2 into high-value chemicals and fuels.It is a viable solution to address the sharp increase in atmospheric CO2 concentration and global warming.However,in traditional neutral or alkaline electrolytes,eCO2RR suffers from severe carbon loss,resulting in a theoretical single-pass carbon conversion efficiency(SPCE)of less than 50％,and the regeneration of the electrolyte requires additional energy.Acidic electrolytes can effectively solve the carbon loss issue,achieving a theoretical SPCE of 100％,which has attracted widespread attention worldwide.Nevertheless,most previous studies focused on catalyst optimization,with insufficient emphasis on optimizing solid-liquid-gas interfaces such as gas diffusion electrodes(GDEs),electrolytes,and proton membranes.These factors influence the selectivity,stability,and energy efficiency of eCO2RR.In this study,we systematically optimized the three-phase interface(solid,liquid,and gas)of the acidic eCO2RR,achieving a faradaic efficiency for CO(FECO)of over 90％at a current density of 100 mA·cm-2 and a cell voltage of less than 5 V,with stable operation for 110 hours.Finally,we scaled up the electrode area to 100 cm2,exploring the impact mechanism of process scale-up,and proposing a new intermittent operation strategy.This research on interface optimization and process scale-up of acidic eCO2RR is expected to provide a theoretical foundation for its potential industrial applications.
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