Effect of praseodymium oxide and cerium-praseodymium mixed oxide in the Pt electrocatalyst performance for the oxygen reduction reaction in PAFCs

The effect of praseodymium oxide and cerium-praseodymium mixed oxide in the Pt electrocatalyst performance for oxygen reduction reaction (ORR) in Phosphoric Acid Fuel Cells (PAFCs) has been studied. Three electrocatalysts (Pt/C, PtPrOx/C and PtCe0.9Pr0.1Oy/C, where x and y are <= 2) have been prepared and tested by cyclic voltammetry (CV) and long term chronoamperometry (CA) experiments. The fresh and tested electrocatalysts have been characterized by X-ray diffraction (XRD) and Transmission Electron Microscopy-Energy Dispersion Spectroscopy (TEM-EDS). The Pr and Ce-Pr oxides improved Pt dispersion in the fresh electrocatalysts with regard to the Pt-only catalyst, and the PtPrOx/C and PtCe0.9Pr0.1Oy/C electrocatalysts presented a slightly improved catalytic activity towards ORR in comparison to the reference Pt/C electrocatalyst. The activity decay during the long term CA tests was slower for PtPrOx/C and PtCe0.9Pr0.1Oy/C than for Pt/C. Although the Pr and Ce-Pr oxides were dissolved during the CA measurements, the Pt sintering was prevented.