PtNi Alloy Nanoparticles Supported on Polyelectrolyte Functionalized Graphene as Effective Electrocatalysts for Methanol Oxidation

This paper reports the use of a polyelectrolyte, poly(diallyldimethylammonium chloride) (PDDA), for fabricating bimetallic, highly active PtNi nanocatalysts supported on PDDA-functionalized graphene (P-G). The PDDA-Coating creates a distribution of positive charges on the surfaces of G, which is in favor of the electrostatic self-assembly of negatively charged PtCl62- ions and positively charged Ni2+ ions on the P-G, respectively. The subsequent reduction process by ethylene glycol gives PtNi nanoparticles with uniform distribution on the P-G. The as-made PtNi nanocatalysts supported on the P-G show better activity and stability for the electro-oxidation of methanol compared with pure Pt nanocatalyst supported on the P-G and PtNi nanocatalysts supported on G. Most importantly, the as-made Pt2Ni1/P-G and Pt1Ni1/P-G catalysts display higher activity and stability than the commercial Johnson Matthey PtRu/C (20%) catalyst (JM PtRu/C). (C) 2013 The Electrochemical Society. [DOI: 10.1149/2.056303jes] All rights reserved.