Glycerol Oxidation Pairs with Carbon Monoxide Reduction for Low-Voltage Generation of C₂ and C₃ Product Streams

Abstract

Electrochemical carbon dioxide reduction to multicarbon products provides the storage of renewable energy in the form of chemical bonds, as well as a means to displace fossil sources of chemical feedstocks. However, the accompanying anodic oxygen evolution reaction (OER) reduces the energy efficiency of the process without providing a salable product. Replacing OER with alternative organic oxidation reactions (OORs) is an emerging strategy to reduce the full-cell potential and generate valuable products on both sides of the cell. We pursue carbon monoxide reduction that avoids carbonate formation and benefits from highly alkaline anode conditions favorable for OOR. This coelectrolysis strategy achieves a cathodic C2+ product stream (71% FE) and an anodic C3 product stream (75% FE) at 180 mA cm–2 with a full-cell potential of 1.34 V. The integrated system reduces the CO-to-C2H4 energy requirement by 55% (to ∼72 GJ/ton_C2H4), halving the projected energy cost of ethylene production from CO2.