Cover Feature: System Design Rules for Intensifying the Electrochemical Reduction of CO₂ to CO on Ag Nanoparticles (ChemElectroChem 9/2020)

Abstract

The Cover Feature illustrates how mechanistic insights can used to engineer the electrolyte composition and formulate system design rules for intensified electroreduction of CO2 to CO. More information can be found in the Aricle by S. S. Bhargava et al.

Continuum Model to Define the Chemistry and Mass Transfer in a Bicarbonate Electrolyzer

“…Carbon dioxide electrolyzers can produce carbon-neutral chemicals and fuels using CO 2 from the atmosphere and electricity from wind and solar resources. − To be industrially relevant, CO 2 electrolyzers must achieve high rates of product formation (i.e., current densities >100 mA cm –2 ) and low cell potentials (<3 V) while also efficiently utilizing the CO 2 reactant. , Gaseous CO 2 is often used as the feedstock for pilot-scale CO 2 electrolyzers because of its solubility and mass transfer advantages over CO 2 dissolved in water. − However, isolating pure CO 2 gas from point sources or the atmosphere is costly because a considerable energy penalty (i.e., 50–175 kJ mol –1 of CO 2 ) is required to liberate CO 2 from liquid sorbents used in CO 2 capture processes. − These collected CO 2 streams are also not often utilized efficiently in gas-fed CO 2 electrolyzers, − since a major fraction of the reacted CO 2 is converted into HCO 3 – and CO 3 2– (referred to here as (bi)­carbonates) upon reacting with OH – produced at the cathode . These (bi)­carbonates are inevitably converted back into CO 2 at the anode .…”