(114c) Divalent Ionic Impurity Driven Changes in Cu-Based CO2 Reduction

Electrochemical CO₂ reduction (CO₂R), utilizing Cu-based catalysts, is a technology capable of converting CO₂ into valuable multi-carbon products, such as ethylene and ethanol, using the simple inputs of CO₂, water, and electricity. Current CO₂R systems utilize ultra-pure deionized water as the electrolyte solvent to maintain high catalytic performance but are not competitive with industrial chemical processes. Operation in real-world water sources provides a potential pathway to improved economic competitiveness of CO₂R systems. In this work, we investigated the consequences of ppm concentrations of multivalent cationic impurities (Ca²⁺ and Mg²⁺) commonly encountered in abundant water sources (e.g., seawater, tap water) on CO₂R performance. We show that these ions and their mixtures can negatively affect Cu-based CO₂R performance, promoting loss of total activity and selectivity towards CO₂R products. Through the stepwise addition of these ions to the electrolyte, we investigated the potential influence of ionic impurities on Cu catalyst reconstruction and the resultant consequences on CO₂R performance.