One-pot facile decoration of graphene nanosheets with Ag nanoparticles for electrochemical oxidation of methanol in alkaline solution

Hybrid nanomaterials (GAg) of graphene nanosheets and Ag nanoparticles (Ag NPs) were prepared by a one-pot reduction of both Ag+ and graphene oxide (GO), and studied for electrochemical oxidation of methanol in alkaline solution. From TEM, XRD and other measurements, the crystalline Ag NPs with a typical diameter of 5–15 nm were homogeneously decorated on graphene nanosheets without aggregation, while their densities (25.6%–61.0%) could be easily controlled by changing the synthesis ratio of graphene oxide nanosheets to Ag+. Cyclic voltammograms results reveal that the GAg materials had the increased electrocatalytic activity (reversed catalytic peak current: 0.22 × 10− 5 A–1.01 × 10− 5 A) with the increase of Ag NPs loading for methanol oxidation in alkaline solution, and the catalytic current was linear to the concentration of CH3OH. At last, the stability of GAg catalysts-modified electrodes and the influence of catalytic reaction temperature towards methanol oxidation were also investigated. The facile synthesis, low cost and high activity of the GAg materials make them have great potential applications in the direct methanol alkaline fuel cells (DMAFCs).

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► Developing a cost-saving method to synthesize GAg nanomaterials with different loading amount of Ag NPs.
► The GAg was used as a stable catalyst for methanol oxidation in alkaline solution at a much lower potential.
► The GAg showed the increased electrocatalytic activity with the increase of Ag NPs loading.
► The catalytic current was linear to the concentration of CH3OH in solution.
► The GAg is a promising nanomaterial in the application of DMAFCs.