Shape-controlled electrodeposition of silver using chitosan as structure-directing agent on disposable pencil graphite e
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ORIGINAL PAPER
Shape-controlled electrodeposition of silver using chitosan as structure-directing agent on disposable pencil graphite electrodes: low-cost electrocatalysts for the detection of hydrogen peroxide and hydrazine hydrate S. Preethi 1 & M. V. Sangaranarayanan 1 Received: 26 February 2020 / Revised: 26 March 2020 / Accepted: 26 March 2020 # Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract A facile synthetic protocol for the electrodeposition of diverse morphologies of silver on disposable pencil graphite electrodes (Ag/PGE) in the presence of chitosan as structure-directing agent (SDA) is reported. The influence of various electrodeposition parameters on the morphology of Ag deposited has been studied and interpreted using electron microscopic techniques. Several impressive morphologies such as hexahedron, leaf and dendrites have been observed for Ag/PGE with respect to change in experimental conditions. Furthermore, the crucial role of chitosan in determining the morphology of Ag/PGE has been elucidated with the help of three-dimensional Scharifker-Hills nucleation and growth model. The electrocatalytic activities of various Ag/ PGEs towards the reduction of hydrogen peroxide (HP) and oxidation of hydrazine hydrate (HH) have been studied in detail with the help of diverse electrochemical techniques. In comparison with PGE, the Ag hexahedron- (Ag-Hex/PGE) and Ag dendrite(Ag-Dend/PGE) modified PGEs exhibited excellent electrocatalytic activity towards HP and HH, respectively. The Ag-Hex/PGE displayed a wide linear range of 0.1–20,000 μM with a limit of detection (LOD, 3σ/m) of 0.06 μM for HP reduction. On the other hand, a linear range of 25–20,000 μM with LOD of 1.8 μM for HH oxidation has been observed for Ag-Dend/PGE. Furthermore, the modified Ag/PGEs revealed remarkable reproducibility and long-term storage stability. The practical applicability of the AgHex/PGE and Ag-Dend/PGE was demonstrated through the electrocatalytic detection of HP in milk and HH in tap water samples with satisfactory recovery results. Keywords Chitosan . Silver nanoparticles . Pencil graphite electrode . Hydrogen peroxide . Hydrazine hydrate . Scharifker-Hills model
Introduction The modification of electrode surfaces with nano-sized metal and semiconductor particles has garnered much interest during the past few decades of electroanalytical chemistry [1–4]. In catalytic and electrocatalytic reactions, the crucial role played by the nanoparticles has been extensively researched. However, the catalytic behaviour of the metal nanoparticles (MNPs) depends primarily on their surface to volume ratio and its electronic level interactions with the reactant species * M. V. Sangaranarayanan [email protected] 1
Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, India
[5–9]. In addition to their excellent catalytic activities, MNPs exhibit unusual physicochemical properties in comparison with the bulk metals [4, 10–14]. This unusual property of MNPs has been mainly attributed to their q
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