One pot synthesis of pt/graphene composite using polyamidoamine/chitosan as a template and its electrocatalysis for methanol oxidation

Abstract

A one-pot hydrothermal strategy was used to synthesize Pt/GNs (PAMAM) & Pt/GNs (CS) composites. Pt nanoparticles are deposited onto graphene sheets (GNs) via synchronous reduction of K2PtCl4 and graphene oxide (GO) under hydrothermal conditons without additional reducing agent. During the synthesis process, polyamidoamine (PAMAM) or chitosan (CS) was used as a template respectively to obtain shape controlled Pt particles on the surface of GNs, leading to the formation of flower-like Pt nanoclusters for Pt/GNs (PAMAM) and uniform spherical Pt nanoparticles for Pt/GNs (CS). PAMAM and CS are simultaneously served as intrinsic reducing agents to accelerate reduction process; ensuring excellent electrical conductivity of the composites. Electrochemical tests show that Pt/GNs (PAMAM) and Pt/GNs (CS) have much higher electrocatalytic activity and better stability toward methanol oxidation reaction (MOR) in comparison with counterpart Pt/GNs and the commercially available 20% Pt/C catalyst (Pt/C) due to their better dispersion of Pt particles, stronger interaction between Pt and substrate materials, and better electron transfer capability.