A novel strategy to achieve simultaneous efficient formate production and p-nitrophenol removal in a co-electrolysis system of CO2 and p-nitrophenol

A co-electrolysis system of CO2 and organic pollutants (CES) is promising for CO2 conversion and organic pollutant removal. However, it is still challenging to achieve the simultaneous efficient CO2 conversion and organic pollutant removal by tuning the electrode potential. Herein, we report a novel electrolysis mode for the CES. The anode potential was controlled by a potentiostat, while the cathode potential was controlled by changing the cathode surface area. By controlling the anode potential at 1.8 V and the cathode surface area at 0.1 cm2 (i.e., the anode/cathode surface area ratio was 10), both the anode and cathode potential values in the CES could be maintained to where CO2 reduction to formate and organic pollutant (p-nitrophenol in this study) removal were favored. The efficiencies for formate production and p-nitrophenol removal were almost the same as their optimal values in the individual electrochemical processes. Moreover, compared to the conventional electrolysis mode, our proposed electrolysis mode increased the current efficiency 1.25–1.41 times. Overall, this study clearly demonstrated that our proposed electrolysis mode is a feasible strategy to obtain simultaneous efficient formate production and organic pollutant removal in the CES, which can accelerate the use of the CES in industrial applications.