Global warming is a critical issue requiring immediate action towards net-zero emissions. Proton Exchange Membrane Fuel Cells (PEMFCs) are seen as a key technology in this shift by reducing reliance on fossil fuels. The effectiveness of PEMFCs largely depends on the development of catalysts, particularly for the Oxygen Reduction Reaction (ORR) at the cathode. Presently, platinum-based catalysts dominate, but they are expensive and scarce, limiting overall PEMFC efficiency. This thesis addresses three main challenges in PEMFC catalyst development: lack of intermediate testing platforms, understanding of local transport dynamics, and efficient catalyst layer architecture.
The research employs an interdisciplinary approach, combining materials science, electrochemistry, and engineering. A Gas Diffusion Electrode (GDE) was developed for realistic ORR measurement conditions. To enhance ionomer interaction with the catalyst, the study used biomass-derived carbon nanostructures, specifically creating 4nm mesopores in hydrothermal carbonization of xylose. This structure showed improved ORR efficiency, confirmed by operando X-ray Absorption Spectroscopy measurements and structural characterization.
Furthermore, a freestanding carbon film with a hierarchical architecture was designed, using lignin and dual templating techniques for better mass transport and ORR performance. This architecture especially improved performance in mass transport-dominant areas.
In conclusion, the thesis systematically tackles key barriers in PEMFC catalyst layer development. Through experimental innovation and strategic integration of various scientific principles, it offers a rational design strategy for advancing PEMFC technology. This contributes valuable insights and practical solutions for sustainable energy development in the fight against climate change.