Performance of Pd/C Cathode Electro-Catalysts for the ORR in Sulfuric Acid Containing Small Organic Molecules

Abstract

We studied the performance of carbon-supported Pd cathode electrocatalysts in O 2 -saturated acid solution containing ethanol. The Pd/C electrocatalysts showed an important selectivity toward the Oxygen Reduction Reaction (ORR), and a very high degree of tolerance to poisoning due to the presence of the alcohol. A negative shift in onset potential for the ORR of only 10 mV for a 20% Pd/C electrocatalyst in 0.5M H 2 SO 4 + 0.125M C 2 H 5 OH electrolyte was measured, whereas the shift for a 20% Pt/C electrocatalyst was of 398 mV in the same solution. Similar high tolerances were established at increasing C 2 H 5 OH concentrations for Pd/C.