Bifunctional Pd‐CeO2 Nanorods/C Nanocatalyst with High Electrochemical Stability and Catalytic Activity for the ORR and EOR in Alkaline Media

Abstract

AbstractThe catalytic activity and electrochemical stability of Pd‐CeO2‐NR/C (CeO2‐NR: cerium oxide nanorods) for the Oxygen Reduction Reaction (ORR) and the Ethanol Oxidation Reaction (EOR) is shown in alkaline media and compared to Pd/C. Evaluation of catalytic activity for the ORR in a Rotating Ring Disc Electrode (RRDE) set‐up, shows that Pd‐CeO2‐NR/C promotes the reaction with a percentage of hydrogen peroxide production (%H2O2) around 2–4 %, and an electron transfer number (n) close to 4. Tafel plots demonstrates higher mass and specific activities of Pd‐CeO2‐NR/C than Pd/C. Moreover, from cyclic voltammetry tests, Pd‐CeO2‐NR/C shows a higher mass catalytic activity (jm= 697 mA mg−1Pd) for the EOR at a more negative onset potential (Eonset= 0.29 V/RHE) than Pd/C. After Accelerated Degradation Tests (ADT), Pd‐CeO2‐NR/C retains ∼98 % of its Electrochemically Active Surface Area (ECSA), higher than ∼51 % of Pd/C. After ADT, the performance of Pd‐CeO2‐NR/C remains similar for the ORR, while it is significantly higher for the EOR, compared to Pd/C. Thus, the addition of CeO2‐NR enhances the electrocatalytic behavior and stability of Pd towards the ORR and the EOR.