Enhanced electrocatalytic activity of high Pt-loadings on surface functionalized graphene nanosheets for methanol oxidation

•Pt nanoparticles were deposited on diallyldimethylammonium chloride modified graphene oxide.•High Pt metal loadings, up to 85 wt. % with a mean size of 1.4 nm, were in situ decorated on PDDA-graphene surfaces.•PDDA functionalized graphene provided the higher electrochemical active surface area.•Surface area and size of modified catalysts explain the improved electroactivity and the stability.

Here we report a simple one-pot microwave-polyol reduced method to anchor platinum nanoparticles on graphene with the aid of poly (diallyldimethylammonium chloride) (PDDA), forming a Pt/PDDA–G hybrid (Pt/PDDA–G). High Pt metal loadings, up to 85 wt.% with a mean size of 1.4 nm, were densely in situ decorated on PDDA-modified graphene surfaces. The electrochemical tests showed that the activity and stability of Pt supported on PDDA–graphene hybrid substrates for methanol oxidation were better than that of Pt supported on graphene sheets, also better than the widely used Pt/carbon black electrocatalysts with the same Pt content on the electrode. This improved activity indicates that PDDA plays a crucial role in the highly dispersion and stabilization of Pt nanoparticles on graphene and PDDA–G are able to an alternative support for Pt immobilization in direct methanol fuel cells.