Electrocatalysis of Graphene based Nanocomposites for Cathodic Oxygen Reduction Reaction

Abstract

Abstract: newlinea) Objectives: The main objective of the present work is largely focused on the fabrication of Pt M (M = Fe, Co, and Ni) bimetallic nanoparticles supported on reduced graphene oxide (RGO) layers, Pt-Cu/RGO-TiO2, MgO-supported multi layered graphene oxide (MLGO) as electrocatalyts for oxygen reduction reaction (ORR) a principle reaction involved in proton exchange membrane fuel cells (PEMFCs). Characterization of graphene oxide (GO), RGO, electrocatalysts in terms of morphology, structure etc. by Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), selected area electron diffraction (SAED) and cyclic voltammetry (CV). Systematic electrochemical studies were done on synthesized electrocatalysts by performing cyclic voltammetry (CV), linear sweep voltammetry (LSV) using rotating disk electrode (RDE) setup to evaluate ORR performance in acidic and alkaline electrolytes. ORR activity descriptors like mass-specific and area-specific current density, onset potential, potential at half-wave (E1/2) were evaluated for the fabricated catalysts and compared with commercial Pt/C catalysts. newline newlineb) Methodology: newlineFabrication of GO: For the fabrication of graphene oxide (GO), modified Hummer s method was utilized. In the synthesis of GO from natural graphite, pomegranate peel extract (PPE) is utilized for the purpose of neutralization in place of NaOH. newline newlineFabrication of Pt3Co and Pt3Ni/RGO and ORR activity studies: For the fabrication of bimetallic Pt M (M = Co or Ni)/RGO nanoparticles, a simple wet chemical method using ascorbic acid as a reducing agent was employed. For the comparison purpose platinum nanoparticles deposited on reduced graphene oxide (RGO) with Pt loading of 30 wt% on RGO was also prepared using ethylene glycol as reducing agent. From the TEM analysis, the average particle size of Pt/RGO, Pt3Co/RGO and Pt3Ni/RGO particles were found to be 3.3, 1.2 and 2.25 nm, respectively. The ORR activity of as