Investigating the Role of Cations in the Electrochemical Reduction of Carbon Dioxide

Decarbonising the chemical industry is one of the greatest challenges in the path to net zero. Among the most-energy-intensive products are ethylene, propylene, and methanol, chemicals whose large-scale production drives some of the industry’s highest CO₂ emissions.  Their environmental footprint makes them prime targets for the development of cleaner, more sustainable synthesis routes.

One promising route is through CO₂ electrolysis - a process by which water and carbon dioxide are converted into oxygen and carbon-based products using an electric current and a catalyst. The catalyst plays a central role in determining selectivity. Copper-based catalysts, in particular, can facilitate the formation of carbon-carbon bonds, enabling the production of valuable multi-carbon (C₂) products. The electrolyte also critically influences the product selectivity. Potassium-based electrolytes are often employed, as potassium ions enhance the binding strength of the copper-carbon intermediates, thereby improving the formation of C₂ products. When these systems are scaled into device level membrane-electrode assemblies, the same drive in selectivity is lost, partly due to the loss of the potassium ions from the supporting electrolyte.

This project will use a unique size-selected deposition source to produce copper nanoparticles uniformly across a carbon support at a desired size. This highly controlled catalysts will then be studied electrochemically, in device level electrolysers down to rotating disk electrode and lab flow cell measurements to study the effect of electrolyte composition on the selectivity. Mechanistic insight will be gained through operando X-ray characterisation of the catalyst-electrolyte interface, utilising both soft and hard x-rays to probe the changes at this interface. These measurements are typically conducted at synchrotron facilities, meaning that there will be many opportunities to work at these facilities including the nearby Diamond Light Source as well as others internationally.

Any questions concerning the project can be addressed to Prof Robert Weatherup (robert.weatherup@materials.ox.ac.uk).

General enquiries on how to apply can be made by e mail to graduate.studies@materials.ox.ac.uk.  You must complete the standard Oxford University Application for Graduate Studies.  Further information and an electronic copy of the application form can be found at https://www.ox.ac.uk/admissions/graduate/applying-to-oxford.