Amperometric assay of hydrazine utilizing electro-deposited cobalt hexacyanoferrate nanocrystals on graphene oxide sheet
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Bull Mater Sci (2020) 43:245 https://doi.org/10.1007/s12034-020-02219-y
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Amperometric assay of hydrazine utilizing electro-deposited cobalt hexacyanoferrate nanocrystals on graphene oxide sheets MAMTA YADAV, VELLAICHAMY GANESAN* , RUPALI GUPTA, DHARMENDRA KUMAR YADAV and PIYUSH KUMAR SONKAR Department of Chemistry, Institute of Science, Banaras Hindu University, Varanasi 221005, India *Author for correspondence ([email protected]; [email protected]) MS received 19 November 2019; accepted 22 February 2020 Abstract. In-situ electrochemical deposition of cobalt hexacyanoferrate (CoHCF) on graphene oxide (GO) and its application for the electrocatalytic hydrazine determination in real samples are described in this research study. Co2? is immobilized on GO and the resulting material, GO-Co2? is coated on the surface of glassy carbon (GC) electrode. The fabricated electrode (GC/GO-Co2?) is subjected to a continuous potential cycling in the range of 0.0–1.0 V which results in the formation of a thin CoHCF film on the surface of GO coated on the GC electrode (abbreviated as GC/GO-CoHCF). The synthesized GO-CoHCF composite material is characterized by Fourier transform infrared and scanning electron microscopy. GC/GO-CoHCF electrode electrocatalytically oxidizes hydrazine at low overpotential (0.63 V) and this phenomenon is subsequently utilized for the sensitive determination of hydrazine in aqueous solutions. It exhibits a wide linear calibration range (0.1–400 lM), high sensitivity (0.93 lA lM-1 cm-2) and low limit of detection (17.5 nM) for the determination of hydrazine. Further, this electrode is employed for hydrazine determination in real samples. Keywords. Graphene oxide; cobalt hexacyanoferrate; hydrazine oxidation; cyclic voltammetry; amperometry; electrocatalysis.
1.
Introduction
Graphene is a two-dimensional sheet with a single carbon atom thickness containing sp2 hybridized carbon atoms arranged in a honeycomb pattern which makes it the strongest and thinnest rigid material in the world. It is an excellent conductor of heat and electricity. It also exhibits other superior properties like high mechanical strength and high transparency [1,2]. When the contiguous aromatic lattice of graphene is obstructed by certain functional groups (like alcohol, carbonyl, epoxide and carboxylic acid), graphene oxide (GO) is formed [3–7]. The functional groups attached on the basal planes (hydroxyl and epoxide) and on the sheet edges (carbonyl and carboxyl) show efficient bio-compatibility and high water solubility which are quite useful for further functionalization [3–6]. GO is used in several electrochemical sensors and it enhances the sensor sensitivity due to its electrocatalytic properties [3,6,7]. Modification of electrode surfaces by an inorganic film is a very attractive approach for the development of electrochemical sensors [8]. Transition metal hexacyanoferrates (TMHCFs) are polynuclear mixed-valence compounds
having open and zeolite-type structures. They a
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