Highly Active Pd-CeO2-NR/C (Cerium Oxide Nanorods) Bifunctional Nanocatalysts with Remarkable Stability for the Ethanol Oxidation and Oxygen Reduction Reactions in Alkaline Media

Abstract

The electrochemical stability and catalytic activity of Pd-CeO2-NR/C and Pd/C nanocatalysts for the Oxygen Reduction Reaction (ORR) and the Ethanol Oxidation Reaction (EOR) in 0.5 mol L-1 KOH is evaluated in this work. Evaluation by RRDE show that Pd-CeO2-NR/C has a catalytic activity for the ORR similar to Pd/C in terms of onset potential of the ORR (0.97 and 1.0 V/RHE before ADT, respectively; 0.92 and 0.95 V/RHE after ADT, respectively). Nevertheless, Pd-CeO2-NR/C delivers higher mass and specific activities that Pd/, with both nanocatalysts producing about the same amount of H2O2 (between 1 and 4.5 %). Meanwhile, the polarization curves of the EOR before ADT show a peak mass current density of 697.70 mA mgPd -1 generated by Pd-CeO2-NR/C (at 0.86 V/RHE), higher than 665.66 mA mgPd -1 obtained from Pd/C (at 0.92 V/RHE). After ADT, the mass current density increased by 1.6 and 1.4 times at Pd-CeO2-NR/C and Pd/C, respectively. The results work show that Pd-CeO2-NR/C is a highly electrochemically stable bifunctional nanocatalysts with high catalytic activity for the ORR and the EOR in alkaline media, which make it a promising candidate for AEMFCs applications.