The poisoning effect of tetrachloroethylene (TTCE) on the activity of a Pt fuel cell catalyst for the adsorption and activation of H-2 was investigated at 60 degrees C and 2 atm using hydrogen surface concentration measurements. The impurity was chosen as a model compound for chlorinated cleaning and degreasing agents that may be introduced into a fuel cell as a contaminant at a fueling station and/or during vehicle maintenance. In the presence of only H-2, introduction of up to 540 ppm TTCE in H-2 to Pt/C resulted in a reduction of available Pt surface atoms (measured by H-2 uptake) by ca. 30%, which was not enough to shift the H-2-D-2 exchange reaction away from being equilibrium limited. Exposure of TTCE to Pt/C in a mixed redox environment (hydrogen + oxygen), similar to that at the cathode of a fuel cell, resulted in a much more significant loss of Pt surface atom availability, suggesting a role in TTCE decomposition and/or Cl poisoning. Regeneration of catalyst activity of poisoned Pt/C showed the highest level of recovery when regenerated in only H-2, with much less recovery in H-2 + O-2 or O-2. The results from this study are in good agreement with those found in a fuel cell study by Martinez-Rodriguez et al. [2] and confirm that the majority of the poisoning from TTCE on fuel cell performance is most likely at the cathode, rather than the anode. (C) 2011 Elsevier B.V. All rights reserved.