Microstructural and electrochemical properties of vertically aligned few layered graphene (FLG) nanoflakes and their application in methanol oxidation

Abstract

Vertically aligned few layered graphene (FLG) nanoflakes were synthesised on silicon substrates by microwave plasma enhanced chemical vapour deposition (MPECVD) method. Transmission electron microscopy (TEM) shows that the structures have highly graphitized terminal planes of 1–3 layers of graphene. Raman spectroscopy revealed a narrow G band with a FWHM of ∼23 cm −1 accompanied by a strong G′ (2D) band, with a FWHM of ∼43 cm −1 and an I G / I G′ ratio of 1, which are all the characteristics of highly crystallized few layered graphene. The FLG electrodes demonstrate fast electron transfer (ET) kinetics for Fe(CN) 6 3−/4− redox system with an electron transfer rate, Δ E p, of 60 mV. Platinum (Pt) nanoparticles of ∼6 nm diameter were deposited on as grown FLGs using magnetron DC sputtering for methanol oxidation studies. When used as electrodes for methanol oxidation, a mass specific peak current density of ∼62 mA mg −1 cm −2 of Pt is obtained with a high resistance to carbon monoxide (CO) poisoning as evident by a high value of 2.2 for the ratio of forward to backward anodic peak currents ( I f/ I b).