Proton Exchange Membrane Fuel Cells (PEMFC) operating at temperatures between 50 and 100˚C are now widely regarded as a suitable system for a range of low temperature power generation applications. Development of PEMFCs using perfluorinated cation exchange membranes such as Nafion, which is a popular solid electrolyte for use in PEMFCs, is hampered due to slow cathode electrode kinetics and high costs of membrane and catalysts. Consequently, considerable attention is given to PEMFCs employing an Alkaline Electrolyte Membrane (AEM) since low cost transition metal or transition metal oxides can be used as catalysts for hydrogen oxidation and/or oxygen reduction. It is well known that electro-reduction of oxygen in alkaline media is kinetically faster than the same process in acidic media. Nevertheless, the performance obtained by such cells is far lower than that of PEMFCs employing Nafion as membrane.
In this work, new transition metals (especially silver has demonstrated to be a promising alternative to platinum based catalysts in several studies) and/or their oxides will be tested under alkaline conditions. Likewise, the current available platinum based catalysts will also be tested in acidic media in order to optimize the composition which leads the best performance. Since electro-chemical processes taking place in the catalyst layer are interrelated, other concerns such as ionomer composition, MEA fabrication or even catalyst loading should be optimized in order to get the best performance. Techniques for fuel cell characterization will be employed, mainly i-V measurements, Electro-chemical Impedance Spectroscopy and Cyclic Voltametry, which have demonstrated to be promising tools to understand the behaviour of fuel cells.