Effects of silicotungstic acid on the physical stability and electrocatalytic activity of platinum nanoparticles assembled on graphene

A novel electrocatalyst, Pt@H4SiW12O40/graphene (simplified as Pt@SiW12/GN), was prepared by microwave-assisted reduction method, in which Pt nanoparticles were assembled on reduced graphene and silicotungstic acid was used as a stabilizer to prevent Pt nanoparticles from aggregation. Pt@SiW12/GN was characterized by EDS, XRD, TEM, and XPS analysis. The electrocatalytic activities for methanol oxidation were also investigated. It is found that SiW12 facilitates the formation of uniform Pt particles with an average particle size of 7.5 nm. Most importantly, Pt@SiW12/GN catalyst displays higher electrocatalytic activity, higher stability, and better tolerance to CO when it is compared with Pt/GN catalyst prepared by the same method. The enhancement in electrochemical performance of the Pt@SiW12/GN catalyst system can be attributed to the synergistic effect of highly dispersed Pt nanoparticles on the GN and increased oxidation power of SiW12 that promotes the removal of the poisonous species on the Pt surface.