Electroreduction of CO2: Advances in the Continuous Production of Formic Acid and Formate

The study of the electrochemical CO2 reduction to obtain formate (HCOO-) or formic acid (HCOOH) is receiving much attention as a promising technology. Since continuous-mode operation has become necessary for practical implementation of electrochemical CO2 reduction, recent years have seen a rapid increase in the number of research approaches focusing on this aspect. This Focus Review provides a unified discussion of the available studies on the continuous electroreduction of CO2 to HCOO-/HCOOH, considering the different important features of process design. Moreover, this paper quantitatively assesses the performance of different studies that involve continuous electrochemical reactors for converting CO2 to HCOOH/HCOO-, comparing relevant typically used figures of merit, including energy consumption. Although some relevant trade-offs have already been achieved, the simultaneous optimization of all the figures of merit remains a challenge. Finally, concluding remarks highlight the detected trends and discuss relevant aspects that will have to be tackled by future studies in this field.