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

• Published in: Journal of alloys and compounds 2019-08, Vol.796, p.185-195
• Main Authors: Nivetha, Ravi, Grace, Andrews Nirmala
• Format: Article
• Language: English
• Subjects: Charge transfer; Electrocatalysts; Electrochemical impedance spectroscopy; Electrode polarization; Ferrites; Graphene; Hydrogen; Hydrogen evolution reaction (HER); Hydrogen evolution reactions; Hydrogen production; Hydrogen reduction; Manganese; Microscopy; Morphology; Nanocomposites; Scanning electron microscopy; Tafel polarization; Transmission electron microscopy; Voltammetry; X-ray diffraction; Zinc ferrites
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2019.05.021

MnFe2O4/Graphene and ZnFe2O4/Graphene Nanocomposites (MFG & ZFG) were synthesized by solvothermal 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 1.47H2/s and 1.09H2/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 8.5Ω and 13.0Ω was calculated for MFG and ZFG electrocatalysts respectively. The kinetic parameters indicated that the reaction was governed by Volmer mechanism. [Display omitted] •Ferrites and Graphene nanocomposites were tested on HER electrocatalysts.•It showed a good activity with low onset potential.•Catalyst shows good HER performance due to synergistic effect.