Evaluating the Influence of PEMFC System Contaminants on the Performance of Pt Catalyst via Cyclic Voltammetry

Using cyclic voltammetry as a quick ex situ screening tool, the impact of the extracted solution and the individual leachable constituents from prospective balance of plant component materials on the performance and recoverability of the platinum catalyst were evaluated. Taking an extract from Zytel HTN51G35HSLR (polyphthalamide) as an example, the major leachable organic components are caprolactam and 1,6-hexanediol. While these organic compounds by themselves do poison the Pt catalyst to some extent, such influence is mostly recoverable by means of potential holding and potential cycling. The extracted solution, however, shows a more drastic poisoning effect and it was not recoverable. Therefore, the non-recoverable poisoning effect observed for the extracted solution is not from the two organic species studied. This demonstrates the complexity of such a contaminant study. Inorganic compounds that are known poisons (like sulfur) even in very low concentration may have a more dominant effect on the Pt catalyst and the recoverability.