Functionalization of Glassy Carbon Electrodes with Metal-Based Species

Abstract

Substituted phenyl-modified glassy carbon electrodes were functionalized with metal/metal oxide/ metal hydroxide and inorganic compounds. More specifically, the glassy carbon electrodes were first functionalized with 4-sulfonate phenyl and N,N-diethylaniline groups by electrochemical reduction of the corresponding diazonium salt in nonaqueous media. Second, the functionalized electrodes were soaked in a solution containing the metallic ions and treated with a reductant (NaBH 4 ) in the case of the formation of the Ru-and Cu-based species or with redox species (Fe(II) or Fe(CN) 6 3-) in the case of Prussian Blue. The resulting Cu/Cu(OH) 2 and RuO 2 /Ru(OH) 2 -modified glassy carbon electrodes displayed electrochemical activity for selected reaction such as nitrate reduction and hydrogen peroxide oxidation, respectively. X-ray photoelectron spectroscopy was also used to confirm the presence of the metallic species and Prussian Blue at the electrode surfaces. The curve-fitting of the appropriate core level spectra was useful to distinguish between the oxide/hydroxide species and the metallic state. The atomic concentration of the metal-based species at the surface of the modified glassy carbon electrodes, estimated from the XPS data, ranged between 0.2 and 1 at. %, which corresponds to surface concentration of 0.55 × 10 -10 , 0.87 × 10 -10 , and 0.21 × 10 -10 mol/cm 2 for Cu, Ru, and Prussian Blue, respectively. These relatively low surface concentrations and the scanning electron micrographs of copper-or rutheniummodified glassy carbon electrode suggest that very small particles are present at the electrode surface. On the other hand, the presence of submicrometric particles was found to be evident for Prussian Blue formed on the modified surface. In the case of the copper-modified electrode, stripping voltammetry was used to estimate the amount of metallic copper, which was found to be in reasonably good agreement with the XPS data.

Electrocatalytic reduction of nitrate on copper electrodes prepared by high-energy ball milling

“…4c) can be fitted with a peak at 932.8 ± 0.1 eV which corresponds to Cu and/or Cu 2 O with a large shoulder at 935 eV. A shake-up satellite at about 9 eV higher, and two smaller components at 935.6 ± 0.1 eV and 933.7 ± 0.2 eV, are also attributed to Cu(OH) 2 and CuO species, respectively [30][31][32][33][34]. This satellite peak occurs when the core photoelectrons excite valence electrons which go to an unoccupied orbital.…”

Advances in Interfacial Design for Electrochemical Biosensors and Sensors: Aryl Diazonium Salts for Modifying Carbon and Metal Electrodes

“…Hall and co-workers synthesized a hydroquinone derivative of an aryl diazonium salt for electrochemical pH sensing [100] while anthraquinone modified carbon electrodes have been used by Tammeveski for the electrocatalytic reduction of oxygen [101,102]. Furthermore, as mentioned above, we have used 4-carboxyphenyl aryl diazonium salt modified carbon electrodes for coupling peptides for detecting metal ions [67] while Bé langer and co-workers [103] have modified electrodes with 4-sulfonate phenyl or N,N-diethylaniline groups for complexing metals from which nanoparticles and metal films could be made. OSullivan and co-workers [104 -106] have used o-aminophenol films on glassy carbon electrodes for detecting hydrazine [105], NADH [104] and alkaline phosphatase activity [106].…”

Metallic and bimetallic Cu/Pt species supported on carbon surfaces by means of substituted phenyl groups

“…After removal of the organic groups by chemical reduction at high temperature the small platinum nanoparticles obtained were in contact with the carbon paper. On the other hand, the formation of metallic particles supported on a substituted phenyl modified glassy carbon electrode was also recently reported [15][16][17]. The procedure based on electrostatic interactions involves the adsorption of metallic ionic species at the phenyl modified carbon electrode which bears functional groups that allow the binding of these ions either electrostatically or through metal-ligand bond formation.…”

“…The procedure based on electrostatic interactions involves the adsorption of metallic ionic species at the phenyl modified carbon electrode which bears functional groups that allow the binding of these ions either electrostatically or through metal-ligand bond formation. Later on, they are electrochemically [15] or chemically [16,17] reduced to form metal particles such as Pt, [15][16][17] Ag, [15] Cu and Ru [16,17].…”