Preparation of electrochemically reduced graphene oxide-based silver-cobalt alloy nanocatalysts for efficient oxygen reduction reaction

The synthesis and performance of electrochemically reduced graphene oxide-based silver cobalt (AgCo/ERGO) alloy electrocatalysts for the oxygen reduction reaction (ORR) are discussed in this study. The surface morphology, alloying nature, and chemical changes of the bimetallic precursors within the AgCo/ERGO catalyst has examined in detail. The presence of poly(ethylene glycol) (PEG) and a cobalt precursor during the electroreduction step is a necessary condition for synthesizing a highly active and stable alloy electrocatalyst for the ORR. Morphological analysis demonstrated that the AgCo nanoparticles (NPs) are homogeneously dispersed on the ERGO support with the assistance of PEG, thus resulting in higher electrochemical surface area and mass activity. X-ray analysis also confirmed the successful formation of the AgCo alloy NPs and the electrochemical reduction of graphene. The direct four-electron transfer pathway for ORR with minimal H2O2 yield has committed at the AgCo/ERGO catalyst over other catalysts. The as-prepared AgCo/ERGO catalyst has shown better electrocatalytic activity, stability, and tolerance to crossover effects compared to the state-of-the-art Pt/C catalyst for ORR. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.