Multi-parameter study of CO2 electrochemical reduction from concentrated bicarbonate feed

The electrochemical reduction of CO2 (CO2RR) from a concentrated (bi)carbonate solution represents novel approach supplying carbon feedstock to reactor. While this achieves comparable performance gas-feed systems, it substantially reduces the amount residual in output, simplifying separation products unreacted CO2. In work, CO 2 M KHCO3 will be studied by determining influence membrane’s polarity, anolyte’s pH and temperature on CO2RR zero-gap flow cell. These parameters were evaluated measuring cell potential, faradaic efficiency (FECO) at current densities (J) between 25 200 mA cm?2. results obtained show that bipolar membranes offer much higher FECO compared cationic or anionic (? 45 % ? 12 cm?2 50 °C) thanks their ability dissociate water produce H+ towards cathode. However, exhibit an important drawback form anolyte doesn’t affect significantly when stays within alkaline value. Also, was confirmed temperatures improve (especially densities) while reducing potential. Finally, determined output gas composition 20 %–55 (at J ? 100 cm-2), well below 60–95 range systems with gaseous feed, demonstrating benefits working bi(carbonate) feed.