Enhanced electrocatalytic performance on polymer-stabilized graphene decorated with alloy nanoparticles for ethanol oxidation reaction in alkaline media

摘要

We explore a green method to grow metal alloy nanoparticles (NPs) on reduced graphene oxide stabilized with polyvinylpyrrolidone (PVP) in aqueous solution with sodium borohydride as a reducing agent for metal ions. PVP was used to stabilize nano-graphene sheets (NGs) in solution and prevent their aggregation. The synthetic experimental conditions were studied to control the size, shape and distribution of alloy nanoparticles anchored on the graphene sheets. AuPt nanoparticles on PVP-stabilized graphene (PVP-NGs-AuPt) show higher catalytic activity and stability than those on graphene without PVP (NGs-AuPt) toward the ethanol oxidation reaction (EOR) in alkaline media. PVP-NGs-AuPt can increase the EOR peak current density by more than 160%, ～100% and 78% as compared with Pt on carbon, AuPt on carbon and NGs-AuPt, respectively. Moreover, the poisoning of PVP-NGs-AuPt during the EOR is less significant than that of NGs-AuPt, as revealed by analyzing the intermediates products, acetate and carbonate, by ion exchange chromatography. The high electrocatalytic activity of PVP-NGs-AuPt is attributed to the surface activation by OH~- and the interaction between the AuPt NPs and graphene, which can improve the CO oxidation within the applied potential range.