Special microwave-assisted one-pot synthesis of low loading Pt-Ru alloy nanoparticles on reduced graphene oxide for methanol oxidation

In this reported work, low loading Pt-Ru alloy nanoparticles (PtRu NPs) have been highly dispersed on reduced graphene oxide (PtRu/RGO) via an auto-power adjusting microwave-assisted one-pot reaction process. The transmission electron microscopy result shows that PtRu NPs with a mean size of ~ 2.99 nm decorated uniformly on RGO. The prepared PtRu/RGO is used as an electrocatalyst for the methanol oxidation reaction (MOR). Compared with the commercial carbon-supported Pt-Ru alloy electrocatalyst, the PtRu/RGO composites demonstrate higher electrochemical active surface area and excellent electrocatalytic activity towards the MOR, such as higher peak current density, lower onset potential and long-term stability. It is deduced that the good performance of the PtRu/RGO towards methanol oxidation could be attributed to the characterised RGO support which provides more effective support and enhances the utilisation of the PtRu clusters, and to the highly dispersed small Pt-Ru alloy NPs resulting from the special microwave heating mode and lower synthesis temperature, which subsequently leads to a valid bifunctional mechanism between Pt and Ru. The present study proves that the PtRu/RGO composites could be a promising alternative catalyst for direct methanol fuel cells and this effective preparation method can be widely applied to other metal/bimetal NPs.