PhD Studentship: Engineering Catalyst-Layer Microenvironments for Selective and Durable Acidic CO₂ ElectrolysisUniversity

Electrochemical conversion of carbon dioxide offers a route to manufacture valuable chemicals using renewable electricity. However, most high-rate CO₂ electrolysers operate under alkaline conditions, where substantial carbon can be lost through carbonate formation. Acidic CO₂ electrolysis could overcome this problem, but introduces a different challenge: intense competition from hydrogen evolution and strong sensitivity to the local

environment inside the catalyst layer. This PhD will investigate how the catalyst-layer microenvironment can be engineered to improve the selectivity and durability of acidic CO₂ electrolysis at technologically relevant reaction rates.

The central hypothesis is that local transport, ionomer chemistry, water availability and ion distributions govern the competition between CO₂ reduction and hydrogen evolution. The student will fabricate gas-diffusion electrodes using well-defined Cu-based reference catalysts,

systematically varying ionomer chemistry, wettability and porous architecture while controlling catalyst composition. Their performance will be evaluated using high-rate acidic CO₂ electrolysis, quantitative product analysis and electrochemical diagnostics. Advanced characterisation will then be used to understand how interfacial transport and local reaction conditions influence multicarbon selectivity and electrode degradation. The aim is to establish transferable microenvironment design principles rather than optimise individual catalyst compositions.

Through collaboration with Professor Ifan Stephens at Imperial College London and the Henry Royce Institute, the project will provide opportunities for specialist mechanistic characterisation and research visits. The project will be embedded within the five-year Royal Academy of Engineering Research Fellowship led by Dr Mengnan Wang on scalable acidic CO₂ electrolysers, providing a strong long-term research platform and links to industrial

collaborators including Johnson Matthey. The successful candidate is expected to join a growing cohort of three to four PhD researchers working on complementary projects, benefiting from peer support, shared expertise and collaborative research opportunities. The outcome will be new understanding and practical design rules for controlling catalyst-layer environments in acidic CO₂ electrolysis, supporting more efficient and durable low-carbon chemical manufacturing.

Funded by: EPSRC Engineering and Physical Sciences Research Council

£21,805. The studentship will provide funding of fees and a stipend of £21,805 per annum for 2026/7.