Fe3+-Clinoptilolite/graphene oxide and layered MoS2@Nitrogen doped graphene as novel graphene based nanocomposites for DMFC

Abstract

Fe3+ doped in a natural zeolite (Fe3+-Clinoptilolite) hybridized with graphene oxide (GO) was used as an electro-catalyst for methanol oxidation in direct methanol fuel cells (DMFC). Furthermore, thin layered molybdenum disulfide (MoS2) composited with nitrogen doped graphene (NG) was used for oxygen reduction. Successful synthesis of these nanomaterials was confirmed by X-ray diffraction (XRD), X-ray florescence (XRF), Fourier transform infrared (FTIR), energy-dispersive X-ray (EDX), Raman spectroscopy, Field Emission Scanning Electron Microscopy (FESEM) and transmission electron microscopy (TEM) images. In the following, by using the cyclic voltammetry (CV) technique the electrochemical behaviors of the glassy carbon electrodes modified with the mentioned composites were investigated. The results of methanol oxidation and oxygen reduction showed sufficient electro-catalytic effects as well as significant diffusion currents in presence of the non-precious synthetic materials. Obtained exchange currents (i0) from Tafel plots showed increasment up to 6.02 × 10−6 and 1.47 × 10−5 μA for anode and cathode respectively. Also, thermodynamic potential of the DMFC was estimated about 1.1 V in alkaline media that was very close to reported value for theoretical potential in DMFC.