Fuel cells represent a promising technology for alternative electricity generation in both automotive and stationary applications. However, at present, cost and durability of the materials employed in fuel cells are barriers to commercial ubiquity. One of the main sources of cost in fuel cells is the platinum or platinum based catalysts used in the electrodes, particularly at the cathode where the sluggish oxygen reduction reaction (ORR) kinetics require high loading of precious metals. An alternative to the more widely studied polymer electrolyte membrane (PEM) acidic fuel cell is the alkaline anion exchange membrane (AAEM) fuel cell. Though the alkaline membranes are less developed than the acidic membranes used in PEM fuel cells, AAEMs are seen as a promising route to cost reduction due to the more facile ORR kinetics in alkaline media. This allows the employment of non-noble metals at the cathode, significantly reducing the amount of precious metals required in the fuel cell. However, the hydrogen oxidation reaction (HOR) kinetics (an often neglected area of study in acidic PEM fuel cells due to the negligible activation losses on the anode) in alkaline are an order of magnitude slower and thus, in order to unlock the potential of cheaper cathode catalysts, more active anode catalysts must be developed before AAEMs can be seen as a true alternative to the more established PEM technology. This thesis describes the synthesis, characterisation and electrochemical activity of a novel carbon-supported PdIr catalyst for the HOR in alkaline media. Initial synthesis methods showed the catalyst to have comparable activity with platinum through electrochemical testing, and on increasing the surface area with improved synthesis a two-fold increase in exchange current density was achieved The catalyst has been characterised with a variety of methods including SEM, HR-TEM, XRD, EXAFS and LEIS, and initial in-situ fuel cell polarisation curves are also presented.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:746018 |
| Date | January 2015 |
| Creators | Jervis, J. R. |
| 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/1471458/ |
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