Abstrakt
The presented research is focused on improvement of platinum utilization in Pt-C composite catalysts for proton exchange membrane fuel cell (PEMFC) applications. A series of 25nm thick nanostructured Pt-C thin films were deposited on carbon paper gas diffusion layer substrates (GDL; Sigracet 29BC) by a single-step magnetron sputtering method.
Total Pt loading in the thin films varied in the range 6.7-9.7 mu g cm(-2) as determined by X-ray photoelectron spectroscopy (XPS). These catalysts were examined for their activity in hydrogen oxidation reaction (HOR) and oxygen reduction reaction (ORR), continuously operating for periods exceeding 24 hours.
The dependence of cell output power on Pt concentration and on the working pressure in the cell was examined. Membrane electrode assembly (MEA) with both magnetron sputtered electrodes and a total (anode + cathode) Pt loading 16.7 mu g cm(-2) was also examined during an extended 250-hour durability test.
A stable power density 0.73W cm(-2) was achieved with cell pressure of 300 kPa. Apart from reasonably small power fluctuations no long-term efficiency loss has been detected.