Ionic Liquid Mediated Decoration of Pt Nanoparticles on Graphene and Its Electrocatalytic Characteristics

Abstract

In most of the conventional ionic liquid (IL) or poly-ionic liquid (PIL) mediated Pt carbon catalyst preparations, IL or PIL are covalently linked to the carbon involving complex reaction procedures. IL or PIL acts as the interface between Pt and carbon which increases the internal resistance of the material resulting in high overpotentials for electrocatalysis. In this regard we present a novel methodology to ionically tag IL to graphene that can easily be removed during the chemical reduction procedure for Pt decoration. We successfully prepared platinum nanparticles decorated on ionic liquid treated graphene (Pt-TMIm-rGO) material using a simple and scalable preparation method and systematically characterized. To understand the electrocatalytic efficiency of the material prepared, oxygen reduction reaction (ORR) and methanol oxidation reaction (MOR) characterization were studied and benchmarked with commercial counterparts. X-ray photoelectron spectroscopy results revealed a modulation of d-band centre of Pt and strong metal substrate interaction that reduced the over potential and increased durability. Pt-TMIm-rGO showed very high mass activity, low over potential compared to its counterparts in both ORR and MOR catalytic reactions. Pt-TMIm-rGO showed a high mass activity of ∼346 A g−1 at 0.9 V vs RHE in the case of ORR and 195.2 mA g−1 in case of MOR at 0.86 V vs RHE.