Removal of Surface Poisoning Improving Hydrogen Oxidation Performance of Pt Catalysts under Basic Conditions

Anion exchange membrane fuel cells (AEMFCs) have been developed so far that the cell performance is getting close to that of conventional proton exchange membrane fuel cells (PEMFCs). For further improvement of AEMFC cell performance, it is necessary to develop catalysis in hydrogen oxidation reaction (HOR) under basic conditions on the anode. Here, significant poisoning of Pt/C under basic conditions is demonstrated by electrochemical active surface area (ECSA) analysis using not only electrochemical measurement but also in situ Pt L3 edge X-ray adsorption spectroscopy (XAS). Furthermore, the in situ XAS analysis reveals that the surface modification of Pt/C with another metal species improves the ECSA of Pt nanoparticles by removal of the surface poisoning, which contributes to the enhanced HOR performance of the modified Pt/C catalysts. Therefore, the removal of poisoning is proposed as a mechanism for improvement of the HOR on Pt based catalysts.