Manganese and zinc ferrite based graphene nanocomposites for electrochemical hydrogen evolution reaction

摘要

MnFe2O4/Graphene and ZnFe2O4/Graphene Nanocomposites (MFG & ZFG) were synthesized by sol-vothermal route and further tested as promising electrocatalyst towards Hydrogen Evolution Reaction (HER). The morphology, structural and electrochemical activity of the nanocomposites were studied by X-ray Diffraction, Scanning electron microscopy, Transmission electron microscopy, Linear Sweep Voltammetry (LSV), Cyclic Voltammetry, Tafel polarization and Electrochemical Impedance Spectroscopy (EIS). MnFe2O4/Graphene and ZnFe2O4/Graphene nanocomposites were found efficient electrocatalysts for hydrogen generation via the hydrogen reduction mechanism. The nanocomposites exhibited good activity in acidic medium with a low over potential (313 mV and 315 mV) and a Tafel slope of 106.4 mVdecade(-1) and 114.3 mVdecade(-1) respectively. An exchange current density of 60.11 mAcm(-2) , 47 mAcm(-2), TOF being 1.47H(2)/s and 1.09H(2)/s was observed for MFG and ZFG. Further, an electrochemical specific surface area of 1.51 mFcm(-2), 0.3 mFcm(-2) and a less charge transfer resistance value of 8.5 Omega and 13.0 Omega was calculated for MFG and ZFG electrocatalysts respectively. The kinetic parameters indicated that the reaction was governed by Volmer mechanism. (C) 2019 Elsevier B.V. All rights reserved.