Direct electrochemical

The central conversion technology, also known as a CO₂ electrolyser, uses electricity to drive a chemical reaction on a catalytic surface. We specifically aim to convert CO₂ directly into higher-energy products like ethylene (C₂H₄), but we also look at other intermediate chemicals. This technology requires electrodes, electrolytes and membranes, and under current operation produces O₂ as a by-product. In addition to the electrochemical device, the direct route requires CO₂ which has been concentred from dilute and industrial sources as an input to the conversion device, recycling and separation of the unreacted CO₂ and unwanted reaction products and DC electricity to power the device and ancillary equipment.

Research challenges

A number of major research challenges in the electrochemical direct route are addressed by the e-Refinery initiative including:

• Determining the required purity of CO₂ from different sources which are suitable for use in a CO₂ electrolyser.
• Designing a scaled-up and scaled-out CO₂ electrolyser which maintains catalytic activity (including current density, cell voltage, catalyst and system stability) even as physical size increases.
• Designing a conversion system where CO₂ utilisation is maximised.
• Understanding the operating constraints of a CO₂ electrolyser device under flexible operation (e.g. intermittency).
• Designing an entire value-chain from CO₂ to product which maximises economic value while being technically feasible (process design, LCA, performance demonstrations).
• Determining the CO₂ avoidance potential from a direct electrochemical route as compared to business as usual.