T. Tesfu-Zeru, M. Sakthivel, J.-F. Drillet
In conventional low temperature PEM fuel cells, catalyst activity and stability rely on adequate structure and morphology of carbon support material, especially at the cathode that is exposed to high potential values. Degree of graphitization as well as pore distribution are decisive parameters for corrosion resistivity, catalyst utilization and mass transport. In this work, hollow graphitized carbon spheres (HGS) with mesoporous structure were tested as catalyst support in middle temperature (100–150 °C) direct methanol fuel cell (DMFC) cathode. Influence of catalyst loading and concentration as well as working temperature on power density was studied in a 5 cm2 laboratory cell. Best results in terms of MEA performance were achieved with a catalyst loading of 2 mgPt cm−2 at both electrodes and an extremely dense Pt concentration on carbon support of 50 and 40 wt% at the anode and cathode, respectively at 110 °C. Additionally, thermal pretreatment of carbon-supported catalyst up to 850 °C led to increase in particle size up to 7 nm and as a consequence to substantial higher ECSA retention during accelerated degradation test (ADT) under half-cell conditions.
Dr.-Ing. Jean-François Drillet
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