(124e) The Role of Anion Exchange Membrane in CO Electroreduction

The electrochemical carbon dioxide reduction (eCO₂RR) into value-added chemicals and fuels offers a sustainable route to close the anthropogenic carbon cycle and store the renewable sources' excess energy into chemical bonds. However, eCO₂RR suffers from poor stability and low energy efficiency at practical reaction rates (>100 mA cm^-2). This reaction can be split into a two-step process to achieve a viable route for eCO₂RR. Initially, CO₂ is reduced to CO, which is further reduced to the desired products such as ethanol, ethylene, acetate, etc. The CO electroreduction has been studied in different reactor designs, such as H-type cell, flow rate cell, and membrane electrode assembly (MEA) configuration. The latest shows desired properties by minimizing both ohmic losses and mass transport limitations. These reactors consist of two electrodes (anode and cathode) divided by a polymer membrane. The membrane facilitates the ion transport between the two electrodes and chemically isolate the occurring electrochemical half-reactions. It should be noted that investigators have conceptualized the use of ion-exchange membranes in order to improve the reaction energy efficiency and rate. However, the impact of membrane properties on reaction selectivity, stability, and efficiency remains unexplored.

This talk will provide insights into the ion-exchange membrane's role in the electrocatalytic reduction of CO. We will show how the membrane properties determine the product crossover, product selectivity, and stability. For example, we will discuss: i) the impact of membrane thickness on the product crossover and applied potential, ii) the role of the membrane on the cell stability, iii) the possibility of various membrane functional groups to tune the reaction selectivity and stability, and iv) the role of counter-ion, ion exchange capacity (IEC), and membrane reinforcement on the cell performance. This work will provide a first step toward designing an ion-exchange membrane with the desired characteristics for CO electroreduction.