Powdered activated carbon and carbon paste electrodes: comparison of electrochemical behaviour |
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Authors: | S Biniak M Paku?a W Darlewski A ?wi?tkowski P Kula |
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Affiliation: | (1) Faculty of Chemistry, N. Copernicus University, Gagarina 7, 87-100 Toruń, Poland;(2) Naval University of Gdynia, 81-103 Gdynia, Poland;(3) Institute of Chemistry, Military Technical Academy, Kaliskiego 2, 00-908 Warsaw, Poland |
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Abstract: | Commercial activated carbon (Norit R3ex), de-mineralised with conc. HF and HCl, was oxidised (conc. HNO3) and heat-treated at various temperatures (180, 300 and 420 °C). The physicochemical properties of the samples obtained were
characterised by selective neutralisation and pH-metric titration of surface functional groups (acid–base properties), thermogravimetry
(thermal stability—TG), FTIR spectroscopy (chemical structure) and low-temperature nitrogen adsorption (BET surface area).
Thermal treatment of the carbon materials caused the surface functional groups to decompose; in consequence, the chemical
properties of the carbon surfaces changed. Cyclic voltammetric studies were carried out on all samples using a powdered activated
carbon electrode (PACE) and a carbon paste electrode (CPE), as were electrochemical measurements in aqueous electrolyte solutions
(0.1 M HNO3 or NaNO3) in the presence of Cu2+ ions acting as a depolariser. The shapes of the cyclic voltammograms varied according to the form of the electrodes (powder
or paste) and to the changes in the surface chemical structure of the carbons. The electrochemical behaviour of the carbons
depended on the presence of oxygen-containing surface functional groups. The peak potentials and their charge for the redox
reactions of copper ions depended on their interaction with the carbon surface. |
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Keywords: | Activated carbon Surface chemistry Cyclic voltammetry Carbon electrodes |
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