Elimiantion Voltammetry with Potential Shift

TRNKOVÁ, Libuše. Elimiantion Voltammetry with Potential Shift. Online. In 67th Annual Meeting of the International Society of Electrochemistry. 1st ed. Hague, 2016, 1 pp.

Basic information

• Original name: Elimiantion Voltammetry with Potential Shift
• Authors: TRNKOVÁ, Libuše.
• Edition: 1. vyd. Hague, 67th Annual Meeting of the International Society of Electrochemistry, 1 pp. 2016.

Other information

• Original language: English
• Type of outcome: Proceedings paper
• Field of Study: 10403 Physical chemistry
• Country of publisher: Netherlands
• Confidentiality degree: is not subject to a state or trade secret
• Publication form: electronic version available online
• Organization unit: Faculty of Science
• Keywords (in Czech): eliminační voltametrie; rtuťová elektroda; pevné elektrody;rychlost polarizace; potenciálový posun
• Keywords in English: elimination voltammetry; mercury electrode; solid electrodes; scan rate; potential shift
• Tags: NZ

Abstract

The theory of elimination voltammetry with linear scan (EVLS) was published and experimentally verified for reversible, quasi-reversible and irreversible electrode systems [1,2]. To date, this method has found application not only in electroanalysis but also in the study of electroactive inorganic and organic substances on mercury, silver, or graphite electrodes [3-5]. The discussed elimination procedure can be considered a mathematical model of the transformation of current-potential curves; the model eliminates some current components while conserving others. The elimination of chosen particular currents is provided by elimination function defining a linear combination of total currents measured at different scan rates. One total current is chosen as a reference current and the corresponding scan rate is called reference scan rate, vref. For an adsorbed electroactive substance, the function that eliminates the charging and kinetic current components and conserves the diffusion current component yields a specific, sensitive, and well-developed peak-counterpeak (p-cp) signal [6-8]. The paper presents the EVLS transformation of irreversible current-potential curves where irreversible currents can be expressed in the general form Iir = vxY{E+αln(v/vref)}, where the function Y is independent of scan rate v. Then, the EVLS function eliminating the diffusion and charging currents will be transformed for irreversible currents as follows: f(I) = 6.8284I1/2(E-ΔE) – 8.2426I(E) + 2.4142I2(E+ΔE) where we have, for the potential shift, ΔE = (RT/αnF) ln2. Because the αn value is a priori unknown, the potential shift value shall be determined experimentally. Within this context, the shift enables us to determine the αn value, which defines the slowest steps of the investigated electrode process. Importantly, in the general sense, the expanded voltammetry procedure provides the determination of the αn term, which is an operation not commonly achievable with standard electrochemical techniques. Moreover, the experimental verification of theoretical results indicates a significant opportunity for the expansion of an electrode potential range (potential window).

Links

• LD15058, research and development project: Name: Příprava substrátů pro povrchově zesílenou Ramanovu spektroskopii pomocí elektrochemických, elektroforetických a jiskrový výboj využívajících technik. (Acronym: ELE-SERS)

Investor: Ministry of Education, Youth and Sports of the CR