Bifunctional Pd‐CeO <sub>2</sub> Nanorods/C Nanocatalyst with High Electrochemical Stability and Catalytic Activity for the ORR and EOR in Alkaline Media
P. C. Meléndez-González, Esther Sánchez‐Castro, I. L. Alonso-Lemus, R. Pérez-Hernández, B. Escobar, A.M. Garay-Tapia, W. J. Pech-Rodríguez, F.J. Rodríguez‐Varela
Abstract
Abstract The catalytic activity and electrochemical stability of Pd‐CeO 2‐NR /C (CeO 2‐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‐CeO 2‐NR /C promotes the reaction with a percentage of hydrogen peroxide production (%H 2 O 2 ) around 2–4 %, and an electron transfer number (n) close to 4. Tafel plots demonstrates higher mass and specific activities of Pd‐CeO 2‐NR /C than Pd/C. Moreover, from cyclic voltammetry tests, Pd‐CeO 2‐NR /C shows a higher mass catalytic activity (j m = 697 mA mg −1 Pd ) for the EOR at a more negative onset potential (E onset= 0.29 V/RHE) than Pd/C. After Accelerated Degradation Tests (ADT), Pd‐CeO 2‐NR /C retains ∼98 % of its Electrochemically Active Surface Area (ECSA), higher than ∼51 % of Pd/C. After ADT, the performance of Pd‐CeO 2‐NR /C remains similar for the ORR, while it is significantly higher for the EOR, compared to Pd/C. Thus, the addition of CeO 2‐NR enhances the electrocatalytic behavior and stability of Pd towards the ORR and the EOR.