Durability of CO and CO2 Electrolyzers with Copper Electrocatalysts, Gas Diffusion Electrodes, and Anion Exchange Membranes

Abstract

Recent works have shown that the electrochemical reduction of CO2 or CO to C2 products may be carried out at high rates and selectivities using electrolyzers with copper catalysts, gas diffusion electrodes (GDEs), and anion exchange membranes (AEMs). The current densities and Faradaic efficiencies reported for CO2 reduction are similar to those used in the commercial production of chlorine via the Chlor-alkali process; however, other performance metrics related to the energetic efficiency, carbon efficiency, single-pass conversion, crossover, and durability or operating lifetime are also important considerations.Work in our labs indicates that operating lifetimes are typically related to flooding, precipitation, or catalyst deactivation. As shown in Figure 1a, flooding in CO2 electrolyzers is typically observed with a sharp increase in hydrogen production and increased cathode gas flows. Figure 1b shows evidence of carbonate precipitation including variations in cell potential and lower cathode flow.In this talk, we consider the relationships between AEM properties (conductivity, water transport, counter ion transport), binder properties (viz. hydrophobicity), and catalysts on operating lifetimes of CO2 electrolyzers. Figure 1