Electrochemical Capture and Release of Carbon Dioxide

Understanding the chemistry of carbon dioxide is key to affecting changes in atmospheric concentrations. One area of intense interest is CO2 capture in chemically reversible cycles relevant to carbon capture technologies. Most CO2 capture methods involve thermal cycles in which a nucleophilic agent captures CO2 from impure gas streams (e.g., flue gas), followed by a thermal process in which pure CO2 is released. Several reviews have detailed progress in these approaches. A less explored strategy uses electrochemical cycles to capture CO2 and release it in pure form. These cycles typically rely on electrochemical generation of nucleophiles that attack CO2 at the electrophilic carbon atom, forming a CO2 adduct. Then, CO2 is released in pure form via a subsequent electrochemical step. In this Perspective, we describe electrochemical cycles for CO2 capture and release, emphasizing electrogenerated nucleophiles. We also discuss some advantages and disadvantages inherent in this general approach.