Effects of Ethylene Glycol and Caprolactam on the ORR and HOR Performances of Pt/C Catalysts

Ethylene glycol (EG) and caprolactam are two representative contaminant species either present in the fuel cell system or released by fuel cell system materials. The contamination effects of EG and caprolactam on the electro-catalytic performances of a Pt/C catalyst toward the oxygen reduction reaction (ORR) and hydrogen oxidation reaction (HOR) were investigated in acid media using the rotating ring/disk electrode (RRDE) technique. The Pt surface coverage increased with EG and caprolactam concentrations. The H2O2 yield also significantly increased because of the effects of the two contaminants. The EG- and caprolactam-derived adsorbates reduce the ORR and HOR rates and modify the rate-determining step (change in Tafel slope).