A redox-active polymeric network facilitates electrified reactive-capture electrosynthesis to multi-carbon products from dilute CO-containing streams.

Reactive capture - the integration of CO capture with electrochemical upgrade - offers the prospect of improving overall energy efficiency in captured-CO-to-fuels by eliminating the gas-phase CO desorption step, and by further offering a CO-free gas product stream. Two related challenges limit the potential impact of electrified reactive capture today: its propensity to produce lower-value C products (carbon products containing one carbon atom per molecule); and its failure to retain performance when fed dilute streams (e.g. ~1-10% CO). We posit that these could be addressed using catalysts that locally concentrate and activate in-situ generated CO: we integrate a redox-active polymeric network whose polymer fragments undergo reversible reduction during the electrochemical conversion process, enabling electron transfer to CO molecules generated in-situ from carbonate capture liquid. We report as a result a 55 ± 5% C (carbon products containing two or more carbon atoms per molecule) Faradaic efficiency (FE) at 300 mA/cm in an electrochemical reactive capture system in which the electrolysis stage is fed with 1 M KCO. We obtain 56 ± 4 wt% CH in the product gas stream. When we use a dilute stream consisting of 1% CO in N at the KOH capture stage, we retain the C FE to within 85% (relative) of its value achieved in the case of pure CO.