Oxygen depolarised cathode as a learning platform for CO₂ gas diffusion electrodes

Scientists and engineers worldwide are developing carbon dioxide utilisation technologies to defossilise the bulk chemical industry and support global efforts toward net-zero targets. Electrolysis can make oxygenate and hydrocarbon products from CO₂, water, and renewable electricity. Opposed to such striking simplicity, CO₂ electrocatalysis and electrolysers are fraught with challenges hampering the deployment of CO₂ electrolysis on a large scale. The chlor-alkali electrochemical industry has already tackled various issues encountered today in the development of stable CO₂ reduction gas diffusion electrodes (GDEs). The oxygen depolarised cathode (ODC) is a very stable GDE currently used to make multiple kilotonnes of NaOH and Cl₂. In this review, we present the principle of operation of the ODC including bespoke cell designs implemented to deliver year-long process stability. We do this in parallel to discussing the needs of CO₂ electrolysis and close with a proposed CO2 electrolyser design integrating the learning from the development of the chlor-alkali ODC. The rationale is to help advance robust CO₂ electrolysis with industrially relevant performance.