Impact of electrode geometry and operating conditions on the activity and selectivity of the electrochemical CO2 reduction reaction

The electrochemical CO2 reduction reaction (eCO2RR) has the potential to be a useful technique to not only remove carbon from the atmosphere but also to produce value-added products such as CO and C2H4. To date, there has been a lack of research dedicated to understanding how the macroscopic environment of the electrode and the process conditions affect the performance of the eCO2RR. In this work, we show that by optimising the electrode geometry and electrolyte flowrate we are able to increase the selectivity for C2H4, which is strongly correlated to the electrolyte pH at the electrode surface. It is also shown that the well-reported "poisoning" of copper may actually be caused by increasing KHCO3 concentration throughout electrolysis.