Promoting CO(2) reduction in the presence of oxygen with polymer-based gas diffusion electrodes.

The electrochemical reduction of CO(2) is a promising technology that holds the potential to convert waste CO(2) into valuable products. High carbon capture and purification costs hamper economic feasibility and drive scientists to explore the viability of directly using flue gas exhaust streams. However, flue gas impurities, such as O(2), pose a great challenge because O(2) is preferentially reduced over CO(2). Here, we show that careful design of the gas diffusion electrode (GDE) can significantly improve Faradaic efficiency. This work not only unravels how commonly used carbon-based GDEs facilitate O(2) reduction but also succeeds in devising polymer-based alternatives that significantly improve the Faradaic efficiency (>40%) of CO(2) reduction with 5% O(2)-containing feed streams while showing excellent stability for >2 days. These results demonstrate that it is feasible to engineer suitable GDEs for CO(2) reduction with impure feed streams.