Doctoral defence: Jaana Lilloja “Transition metal and nitrogen doped nanocarbon cathode catalysts for anion exchange membrane fuel cells”

On 23 August at 14:15 Jaana Lilloja will defend her doctoral thesis “Transition metal and nitrogen doped nanocarbon cathode catalysts for anion exchange membrane fuel cells” for obtaining the degree of Doctor of Philosophy (in Chemistry).

Supervisors:
Professor Kaido Tammeveski, University of Tartu
Associate Professor Ave Sarapuu, University of Tartu
Research fellow Elo Kibena-Põldsep, University of Tartu

Opponent:
Juan Herranz Salaner, Paul Scherrer Institute (Switzerland)

Summary
Hydrogen is a clean energy carrier that could be the solution to our growing concerns about energy security, environmental pollution and climate change. The proton exchange membrane fuel cells fueled by hydrogen are already used in the transport sector, but their further commercialization is limited by the need for precious metal catalysts. The technology of anion exchange membrane fuel cells (AEMFCs) is currently less developed, however, it gives the opportunity to use much cheaper non-precious metal catalysts. Transition metal-nitrogen-carbon based materials have already shown great promise as electrocatalysts for the oxygen reduction reaction in alkaline medium and thus can be used as cathode materials of AEMFCs.

The aim of the research described in this doctoral thesis was to prepare and study non-precious metal catalysts for the electrochemical oxygen reduction reaction (ORR) and test their applicability in the AEMFC. To prepare the catalysts, nanostructured carbon support materials with varying morphology were used, such as carbon nanotubes, carbide-derived carbon, graphene and commercially available or self-made mesoporous carbon. These carbon materials were doped with nitrogen and transition metals (iron, cobalt, manganese) via simple high-temperature pyrolysis. The effect of different dopants as well as the structure of the support materials on the ORR activity of the catalysts was studied. These materials were used as cathode catalysts in the AEMFC, where they performed very well, with some of them rivalling the commercially used platinum-based catalyst, thus showing that non-precious metal catalysts could indeed replace precious metals in the fuel cells.

MS Teams