A facile synthesis of Fe3O4-Gr nanocomposite and its effective use as electrochemical sensor for the determination of dopamine and as anode material in lithium ion batteries

Abstract

The Fe3O4-Graphene (Fe3O4-Gr) nanocomposite has been synthesized by hydrothermal method and demonstrated its application towards electrochemical sensor and anode for high performance lithium ion batteries. The nanocomposite exhibited cubic face centred Fe3O4 structure with an estimated crystallite size of 25 nm. The additional peak at 2θ = 26.4° from XRD spectrum confirmed the inculcation of graphene in the composite. The embedment of Fe3O4 nanoparticles in graphene sheets was further confirmed from TEM analysis. The FESEM analysis revealed that the cubical shaped Fe3O4 particles were strongly anchored with graphene nanosheets with an estimated grain size of 40 nm. The electrochemical properties of Fe3O4-Gr were studied with the help of cyclic voltammetry (CV), Differential pulse voltammetry (DPV), electrochemical impedance spectroscopy (EIS) and chronopotentiometry (CP). The sensor performance was studied by testing the electrochemical activity of dopamine (DA) in presence of phosphate buffer solution (PBS) as an electrolyte at pH 6 using CV and DPV. The Fe3O4-Gr/Glassy carbon electrode (GCE) sensor showed ultimate sensitivity and selectivity in the presence of uric acid (UA) and acetaminophen (AC). It demonstrated utmost low limit of detection of 0.78 μM towards the detection of DA and satisfactory recoveries in dopamine injection formulation. Moreover, as an anode material for Li-ion batteries, the Fe3O4-Gr nanocomposite delivered high discharge capacity of 920 mA h g−1 and retained 96% capacity even after 30 discharge cycles.