On 3 September at 14.15 Rohit Kumar will defend his doctoral thesis “ZIF-8-derived M-N-C electrocatalysts for oxygen reduction reaction in AEMFC and MFC devices”.
Supervisors:
Prof. Kaido Tammeveski, Institute of Chemistry, University of Tartu
Dr. Marek Mooste, Institute of Chemistry, University of Tartu
Dr. Ivar Zekker, Institute of Chemistry, University of Tartu
Opponent:
Prof. Barbara Mecheri, Department of Chemical Science and Technologies, University of Rome Tor Vergata, Italy
Summary:
The growing global energy demand is increasingly displacing fossil fuels from energy chains. To ensure long-term energy security and deep decarbonization, the world urgently needs highly efficient energy devices, such as hydrogen fuel cells (HFCs), which utilise hydrogen as a fuel and oxygen as an oxidant. However, the sluggish oxygen reduction reaction (ORR) kinetics hinder the commercialisation of HFCs, especially anion-exchange membrane fuel cells (AEMFCs). Despite several innovations in fuel cell design, their widespread adoption still lags desired momentum. Therefore, the aim of the doctoral thesis was to design metal-organic framework-derived carbon-based catalysts capable of substituting for expensive platinum-based catalysts. A comprehensive set of physicochemical and electrochemical techniques was used to examine the structural integrity, pore architecture and ORR performance in a half-cell setup. When these designed transition-metal-doped carbon materials were integrated as cathode catalysts, they significantly enhanced the performance of AEMFCs and microbial fuel cells (MFCs). With the top-performing catalyst material, the AEMFC achieved an outstanding power density of >1 W cm⁻², demonstrating that a high-performance AEMFC device operating with a Pt-free cathode catalyst is entirely achievable. Therefore, this thesis presents a promising pathway to bypass platinum shortages, providing affordable electrochemical energy technology that could meet the energy demands of everyday life.
