Eliminating the need for anodic gas separation in CO<sub>2</sub> electroreduction systems via liquid-to-liquid anodic upgrading.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 35654799.
- Also identified by DOI 10.1038/s41467-022-30677-x and PMC identifier 9163163.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Electrochemical reduction of CO<sub>2</sub> to multi-carbon products (C<sub>2+</sub>), when powered using renewable electricity, offers a route to valuable chemicals and fuels. In conventional neutral-media CO<sub>2</sub>-to-C<sub>2+</sub> devices, as much as 70% of input CO<sub>2</sub> crosses the cell and mixes with oxygen produced at the anode. Recovering CO<sub>2</sub> from this stream adds a significant energy penalty. Here we demonstrate that using a liquid-to-liquid anodic process enables the recovery of crossed-over CO<sub>2</sub> via facile gas-liquid separation without additional energy input: the anode tail gas is directly fed into the cathodic input, along with fresh CO<sub>2</sub> feedstock. We report a system exhibiting a low full-cell voltage of 1.9 V and total carbon efficiency of 48%, enabling 262 GJ/ton ethylene, a 46% reduction in energy intensity compared to state-of-art single-stage CO<sub>2</sub>-to-C<sub>2+</sub> devices. The strategy is compatible with today's highest-efficiency electrolyzers and CO<sub>2</sub> catalysts that function optimally in neutral and alkaline electrolytes.