An insight into Faradaic phenomena in activated carbon investigated by means of the microelectrode technique

Abstract

Cyclic voltammetry was performed on activated carbon particles in a microelectrode setup to investigate the behaviour of an activated carbon with oxygen functionalities.Quinoid type redox peaks were clearly seen in the potential region around -0.5 V vs.Hg/HgO. After polarization below -0.4 V, an anodic peak confirms previous studies using a pristine carbon, but in the present work much higher in intensity. In addition, a corresponding cathodic peak, not previously reported, was also found. The appearance of this pair of peaks in a functionalized carbon may be connected to reversible hydrogen adsorption together with faradaic reactions involving oxygenated functional groups.

An activated carbon monolith as an electrode material for supercapacitors

“…The main alteration in the shape of the cycle is the reduction in the current intensity during the anodic sweep, an effect generally ascribed to carbon oxidation [31]. As described elsewhere [32,33] this oxidative phenomenon is more pronounced in the positive electrode, whereas the negative electrode hardly changes its performance during longterm cycling.…”

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

“…Using a nanoporous carbon derived from SiC with a very low content in functional groups, Zuleta et al [7] observed small but distinct peaks. Under similar conditions, using an activated carbon with functional groups (1.2 mmol/g CO determined by TPD), Malmberg et al [8] described larger peaks in the interval from +0.2 to À0.2 V and +0.2 to À0.9 V vs. Hg|HgO. The nature of the active material studied in this paper differed in structure and in chemical composition from the carbide-derived activated carbon used in previous studies [7,9,10].…”

“…Cyclic voltammograms obtained when increasing the negative potential window for: (a) the microelectrode configuration and (b) the macroscopic electrode configuration. Faradaic peaks seen as humps in the microelectrode set-up (adapted from[8]). …”

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

“…The pseudo-capacitances involving in the oxygen-containing functional group in H 2 SO 4 solution are widely referred [29,30]. The most well documented case is the oxidation/reduction of hydroquinone/quinine groups.…”