Polymer Electrolyte Membrane fuel cells (PEMFC) are clean and efficient electrochemical energy converters that can be adapted to a wide range of domestic and automotive applications. However, large-scale commercialisation is hindered by issues of cost and durability relating to the catalyst layer. This work aims to address the need for cheaper and durable catalysts through the development of novel catalyst and catalyst support. The initial aim of this work is to investigate the potential application of Pd-based alloy catalyst in PEMFC. Pd is about 42% cheaper than Pt and 50 times more abundant on earth. Previous studies have shown that there is a correlation between electronic structure and catalytic activity of Pd binary alloys, and therefore it is possible to design a highly efficient Pd-based alloy catalyst. In this work, Pd-based catalyst was synthesised and characterized electrochemically in ex-situ and in-situ configurations to determine their activity and durability. It was found that Pd-based catalyst could potentially replace Pt as a low-cost anode catalyst. The second part of this work investigated the potential application of graphitic carbon nitride materials as catalyst support. Carbon black is the most widely used catalyst support for state-of-the-art PEMFCs even though it is known to undergo carbon corrosion during operation. Graphitic carbon nitride could offer enhanced durability and activity due to their graphitic structure and intrinsic catalytic properties. In addition, graphitic carbon nitride is low-cost, fairly simple to synthesise and highly tunable. In this work, various graphitic carbon nitride materials were prepared and characterised using accelerated carbon corrosion protocol. They were found to be more electrochemically stable compared to conventional carbon black. Superior methanol oxidation activity is also observed for graphitic carbon nitride supported Pt catalysts on the basis of the catalyst electrochemical surface area. However further work is needed to optimise the deposition and utilisation of metal catalyst on graphitic carbon nitride materials.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:639612 |
| Date | January 2015 |
| Creators | Mansor, N. B. |
| Publisher | University College London (University of London) |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://discovery.ucl.ac.uk/1460064/ |
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