The importance of pH in controlling the selectivity of the electrochemical CO2 reduction

Abstract The CO2 electrochemical reduction reaction (CO2RR) is seen as a promising technology for converting waste CO2 into carbon-based chemicals using renewable electricity to drive the reaction. The technological viability of this process is contingent on reducing CO2 selectively into one product with high current densities. With this purpose, several groups are studding different materials as electrocatalysts to establish relationships between catalyst structure and its performance. While the catalyst is crucial for the reaction, the reaction conditions such as electrolyte, CO2 pressure and working potential also play an important role on the catalytic performance which need to be understood to optimize the process. This work focusses on the effect that the working pH has on the selectivity of the CO2RR and discuss how the process can be optimized by controlling the concentration of protons near the interphase.