A study of Faradaic phenomena in activated carbon by means of macroelectrodes and single particle electrodes

Abstract

a b s t r a c tThe electrochemical behaviour of a chemically activated carbon with oxygen-containing surface groups was studied using a conventional macroelectrode configuration with disc electrodes and the single particle microelectrode technique. The results of both experimental set-ups were compare taking into account the visible peaks of the surface groups, capacitance and Faradaic currents. Galvanostatic cycling and cyclic voltammetry performed at different potential windows clearly indicated that the microelectrode configuration was more sensitive to Faradic phenomena (i.e. oxygenated functional groups). The incorporation of mainly CO 2 -evolving groups after positive polarization may cause the degradation of the carbon material, leading to a distortion in its capacitive behaviour as a result of a restriction of the available surface area.

Galvanically Stimulated Degradation of Carbon-Fiber Reinforced Polymer Composites: A Critical Review

“…Anodic oxidation of graphitic materials in aqueous solutions reportedly leads to formation of surface oxides predominantly composed of carboxylic and phenolic groups [ 300 , 301 , 302 ]. Cathodic polarizaton of carbon surfaces containing “surface oxides” is likely to result in some reduction of these oxides [ 303 , 304 , 305 , 306 ]. Basova et al [ 307 ] studied how the surface modification of carbon fiber composites by oxidation–reduction cycles affected their electrochemical behavior towards oxygen evolution and concluded that the presence of acidic functional groups (such as –COH, –COOH) on the carbon fiber surface enhances the electrochemical interaction between the oxidized carbon fiber surface and electrolyte solution, while the presence of phenolic, hydroxyl, and quinone groups inhibit this interaction.…”

Asymmetric capacitance response from the chemical characteristics of activated carbons in KOH electrolyte

“…Additionally, as calculated according to the Nernst equation, underpotential hydrogen adsorption/desorption process might be occur at À0.9 V vs. Hg|HgO as follows [33]:…”

Influence of Electrolyte Concentration and Temperature on the Capacitance of Activated Carbon

“…The strong basic electrolyte of KOH has frequently been used due its high ionic conductivity. [14][15][16][17] In the present study, we characterized the capacitive behavior of AC electrodes in KOH electrolyte to determine the influence of electrolyte concentration on the capacitance of AC. The relationship between capacitance and electrolyte concentration was investigated as well.…”