Tandem CO2 electrolysis hits high ethylene concentrations with new separation materials
bioengineer.orgA 2026 study in Nature Chemical Engineering by Sarswat et al. shows that tandem CO2 electrolysis can produce high concentrations of ethylene (C2H4) when paired with novel gas separation materials. The process uses a solid oxide fuel cell to convert CO2 to CO, then an electrolyzer to turn CO into ethylene and other hydrocarbons. The new adsorbent materials separate CO2/CO and C2H4/CO mixtures using temperature and vacuum swing adsorption, reducing energy penalties. The researchers built a full techno-economic model covering CO2 capture, electrochemical conversion, and downstream separations. They found that optimized gas separations significantly improve the net present value of a commercial plant. However, the study notes that liquid product concentrations around 1wt% and CO2 capture costs above $50 per tonne remain major economic barriers. The work shifts focus from catalyst development to separation science as a key bottleneck for scaling CO2 electroreduction.