Cyclic voltammetry poisoning effect

This result is consistent with the observed effective poisoning of the CO oxidation reaction as reflected in the increased potential induced by bismuth in the cyclic voltammetry on the supported platinum electrodes (Figure 10a). The voltammetry of CO stripping on the supported catalysts indicates a similar behavior to that found on Pt(llO) in that bismuth results in a higher overpotential for CO oxidation. One must conclude that the morphology of the supported platinum catalyst results in facets more akin to the more open-packed Pt(l 10) surface than the Pt(lll) surface, a conclusion supported by comparison of the bismuth redox chemistry on the supported catalyst and the single-crystal surfaces [77]. 

When NOx are present in the air and/or in fuel cell cathode, NO is easily oxidized to NO2. Mohtadi et al. [98] performed a cyclic voltammetry (CV) study on a fuel cell after it was exposed to NO2 and foimd no oxidation peaks corresponding to adsorbed NO2 species on the Pt surface. This indicated that the poisoning effects of NO2 do not appear to be a catalyst poisoning issues instead, they suggested [98] that the ionomer and/or the catalyst-ionomer interface could be affected by NO2 exposiue through the following reaction ... 

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