Enhancing the Electrochemical Reduction of CO₂ by Controlling the Flow Conditions: An Intermittent Flow Reduction System with a Boron-Doped Diamond Electrode

Abstract

Electrochemical CO2 reduction using an intermittent flow cell system with boron-doped diamond (BDD) as the working electrode is presented. A stop–start motion of the flow conditions in the intermittent cell is created using a piston pump, and this considerably increases the rate of electrochemical conversion of CO2 to HCOOH compared to a continuous flow system. The system works by stopping the flow of the electrolytes at a controlled frequency, which allows for sufficient time for more CO2 anion radicals (intermediate species) to be reduced into HCOOH instead of being washed away from the surface of the electrode. The findings presented here provide an important basis from which the design of CO2 reduction systems for industrial-scale applications can be started.