Towards a Membrane Electrode Assembly for a Thermally Regenerative Fuel Cell

The thermally regenerative fuel cell (TRFC) concept that is analyzed is a polymer electrolyte membrane fuel cell (PEMFC), powered by the electro-oxidation of H2 and the electro-reduction of propiophenone. The main products of this fuel cell should be 1-phenyl-1-propanol and electricity. The 1-phenyl-1-propanol should then be converted back to propiophenone, while hydrogen is regenerated by using waste heat and a metal catalyst (Pd/SiO2).;In conclusion, the viability of the proposed TRFC system was not verified. H3PO4 leaching from the MEA makes it impossible to use H3PO4-doped mPBI as the electrolyte in the final version of the MEA in the TRFC system.;The first objective was to find a compatible polymer that would work as either an ionomer/binding agent and as a membrane in the membrane electrode assembly (MEA) of the TRFC. This was achieved by checking the compatibility of each polymer with 1-phenyl-1-propanol and propiophenone (the alcohol-ketone pair). Catalyst coated gas diffusion layers or catalyst coated membranes were made to test the stability of the polymers in the catalyst bed when exposed to the alcohol-ketone pair. If the polymer was compatible with the alcohol-ketone pair, MEAs were constructed using this polymer. The second objective was to test these MEAs inside a H2/propiophenone fuel cell that would prove the concept of our envisioned TRFC. It was found that the only polymer that was stable in the alcohol-ketone pair was mPBI (m-phenylene polybenzimidazole). The mPBI had to be doped with H3PO4 to enable H + conductivity. Unfortunately, some H3PO4 leached out of the H3PO4-doped mPBI when in the presence of the alcohol-ketone pair. MEAs that were created using H3PO 4-doped mPBI were found to work for H2/air and H2/propiophenone fed PEMFCs. The best performance achieved with the H2/propiophenone powered fuel cell was 6.23 microW/cm2. Unfortunately, the presence of the 1-phenyl-1-propanol product could not be proved by EIS or CV on the fuel cell, or by GC-FID of the cathode effluent. Other unknown products were seen in the GC-FID spectrum of the cathode effluent. Therefore, it is possible that the propiophenone did reduce at the cathode but it produced an unknown product.