Use of the Ferrocene Oxidation Process To Provide Both Reference Electrode Potential Calibration and a Simple Measurement (via Semiintegration) of the Uncompensated Resistance in Cyclic Voltammetric Studies in High-Resistance Organic Solvents

Abstract

Because of its presumed ideal reversible behavior, the oxidation of ferrocene is widely used in cyclic voltammetric studies in highly resistive organic solvents as a means of reference electrode potential calibration. In this study, it is shown that a good estimate of the uncompensated resistance value, needed for reference potential correction and also frequently an input parameter in simulation of the theory, can be obtained simultaneously with the ferrocene reference potential measurement using a simple analysis based on the semiintegral. Application to cyclic voltammetric oxidation of ferrocene in dichloromethane (0.1 M NBu4PF6), under conditions where uncompensated resistances of approximately 2.5 komega are encountered, is used to illustrate the fidelity of the semiintegral method of analysis. Inclusion of this estimated resistance value as the input parameter in a commercially available digital simulation package confirms that the oxidation of ferrocene in dichloromethane represents a close-to-ideal diffusion-controlled reversible process. However, use of the semiintegral method of data analysis also enables detection of subtle forms of nonideality encountered with the ferrocene oxidation process in other media where kinetically controlled adsorption of the ferricenium cation may occur.

Electrode Kinetics and Sensitivity of Nanostructured Electrodes from Different Carbon Fiber Precursor Materials

“…Semiintegral analysis was used to deconvolute the contributions of diffusion and adsorption to the oxidation processes of DA and UA (Figure 2A, B). The presence in the semiintegrals of peaks rather than steady-state current plateaus (Figure 2C, D) [27][28][29] confirms adsorption of DA [9] and UA [28] at all electrodes that were fabricated from different carbon fiber materials. The relative differences in the semiintegrated peak heights indicate different contributions of adsorption [9] to the response of electrodes from different carbon fiber materials and, additionally, reflect the differences in response of DA and UA at these elec- trodes.…”

“…Uncompensated resistance can arise from electrolyte/ solution resistance, R s [27,29], inherent resistivity of electrode materials, R m [31], and may be due to additional resistance of insulating/resistive surface films, R i [20], and the resistance of the electrical contact leads, R c [31]. Experimental and calculated R s values have been shown to agree when the electrode materials have a negligible resistance [27,29].…”

Cyclic voltammetry of biofilms of wild type and mutant Geobacter sulfurreducens on fuel cell anodes indicates possible roles of OmcB, OmcZ, type IV pili, and protons in extracellular electron transfer

“…64 Fick's law of diffusion provides an estimation of the minimum diffusion coefficient (D) of the current-limiting soluble species for this transition to occur at 0. 50 …”

Direct Electrochemical Determination of Thermodynamic Factors in Aprotic Binary Electrolytes

“…14 Essentially, the scan rate is adjusted continuously during the scan, resulting in a linear effective potential vs. time behavior, although the applied potential is non-linear. 18 As oscillations occur for online IR corrections close to 100% of the total uncompensated resistance, R RE-WE , caused by the measurement hardware, it was only possible to correct for 85% of the ohmic drop. As a result, a combined IR correction, consisting of an online IR correction and a subsequent post IR correction is introduced in the following and will be referred to as 85/15 combined IR correction, where 85 denotes the percentage of online IR corrected resistance and 15 the percentage of post IR corrected resistance.…”