Enhanced methanol electro-oxidation activity of electrochemically exfoliated graphene-Pt through polyaniline modification

Pt and Pt-based catalysts are deemed as the popular anode catalysts for direct methanol fuel cells due to their high electrocatalytic activity for methanol oxidation. The structure of the catalyst support is critical to the electrocatalytic performance of the catalysts. In this work, a kind of high-quality graphene (electrochemically exfoliated graphene) with the intact surface is exploited as the catalyst support instead of the popularly used reduced graphene oxide. Pt nanoparticles are successfully synthesized on electrochemically exfoliated graphene and exhibit better methanol electro-oxidation activity than those on reduced graphene oxide. To further raise the electrocatalytic performance of Pt catalysts, the substrate surface is modified by conductive polyaniline. It is found that the interaction of electrochemically exfoliated graphene with polyaniline is much different from the interaction of reduced graphene oxide with polyaniline. The intact surface structure of electrochemically exfoliated graphene is favorable for the combination with polyaniline by ri-ic interactions, which releases more N species for the growth of Pt nanoparticles. The synergistic interaction of Pt and N species can facilitate the dispersion of Pt nanocrystals as well as the electron transport through Pt-based hybrids, thereby further promoting the electrocatalytic properties of Pt catalysts for methanol oxidation. (C) 2020 Elsevier B.V. All rights reserved.