No abstract

20wt.% Pt/C catalyst was loaded at different densities (0.28- 56.7 mgcarbon cm-2) on glassy carbon (GC) disk electrode, and the effect of its agglomeration on hydrogen peroxide formation in oxygen reduction reaction (ORR) was investigated by the rotating ring-disk electrode technique. The formation of H2O2 was enhanced with a reduction in agglomeration of Pt/C. Even in the operating potential range of PEFC cathodes (0.6-0.8 V), 20% of hydrogen peroxide was formed on Pt/C loaded at densities lower than 1.41 mgcarbon cm-2 on GC. These results revealed that series 2-electron reduction pathway, which is negligible on clean bulk Pt surface, exists on Pt nanoparticles supported on carbon. A large amount of H2O2 formation was observed on Pt nanoparticles deposited not only on GC, but also on Au, which indicated that H2O2 formation is not specific to Pt nanoparticles on carbon support.

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