(671d) Electrochemical Reduction of CO to Liquid C2+ Products with Enhanced Selectivities at 100 Bars

Electrochemical reduction of CO₂ is an attractive approach to utilize the captured CO₂ and sustainable synthesis of fuels. Synthesis of C₂₊ products is more attractive and alkaline electrolyte needs to be used for better efficiency. Electrochemical CO₂ Reduction in alkaline media suffers from the loss of CO₂ in the form of carbonates and tuning the selectivity to liquid C₂₊ products is challenging. Direct electrochemical reduction CO in alkaline media alleviates the problem of carbonate formation and C₂₊ products selectivities are much higher in comparison to electrochemical CO₂ reduction. CO electrolysis suffers from mass transport issues as the solubility of CO is very less in water in comparison with CO₂. One way to overcome the CO mass transport issue is to operate the reactor at elevated pressures. High pressures require minimal energy compared to high temperatures; hence, high-pressure electrochemical synthesis of chemicals can be scaled up for decentralized production of chemicals and capital cost will be considerably less for the decentralized production as the volume of the reactor is an exponential function of the cost. In this work, we conduct CO electrolysis at an elevated pressure of 100 bar in a custom designed autoclave on a porous oxide derived Cu catalyst. We report enhanced selectivities (>95 %) towards liquid C₂₊ products such as ethanol, acetates, and n-propanol with a current density > ~-100 mA/cm² at -0.5 V vs. RHE. The enhanced selectivities are attributed to the electrostriction effect that enables higher stabilization of intermediates, and higher surface coverages of reactants. High-pressure CO electrolysis could be a paradigm shift in the decarbonization of chemical manufacturing, and this work would motivate researchers to explore the field.