Promoted Oxygen Reduction Activity of Ag/Reduced Graphene Oxide by Incorporated CoOx

• Very small CoOx particles were incorporated into Ag/rGO composite.
• CoOx could promote the ORR activity of the resulted nanocomposites.
• Underlying mechanism was given to explain the high-performance of CoOx-Ag/rGO.
• Our strategy provides the possiblity to form better Ag-based ORR catalysts.

CoOx incorporated in Ag/reduced graphene oxide nanocomposites (CoOx-Ag/rGO) were synthesized through an one-pot solvothermal method. Electrochemical results showed that CoOx nanoparticles could greatly promote dispersion of anchored Ag nanoparticles and increase the limiting current density for the whole CoOx-Ag/rGO nanocomposites when catalyzing oxygen reduction reaction (ORR) in alkaline medium. With CoOx formation beside the Ag nanoparticles, a much higher current density and a preferable four-electron pathway were achieved for the CoOx-Ag/rGO nanocomposites. Meanwhile, the CoOx-Ag/rGO nanocomposites showed remarkable long-term stability and tolerance toward methanol than the commercially available 20% Pt/C catalyst. More importantly, this work could finally lead to a practical significance for developing high-performance bicomponent electrocatalysts with low-cost for fuel cells and relevant electrochemical technologies.