Steady-state voltammetry at a microdisc electrode in the absence of excess supporting electrolyte for reversible, quasi-reversible and irreversible electrode kinetics

文献信息

发布日期 2012-09-07

DOI 10.1039/C2CP42533E

影响因子 3.676

作者

Stephen R. Belding, Eduardo Laborda, Richard G. Compton

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摘要

The steady-state voltammetry for a one electron reduction, A + e− ⇌ B, is studied at a microdisc electrode in the absence of excess supporting electrolyte. For the first time, the full voltammetric waveshape is numerically simulated. Using a combination of theory and experiment, the voltammetry is investigated as a function of two variables: the concentration of the supporting electrolyte and the electrochemical rate constant. The ‘hemispherical approximation’ (in which a microdisc is assumed to be a hemisphere of the radius) is shown to be valid under weakly supported conditions, for a range of electrochemical rate constants . The simulations were used, in conjunction with the Debye–Hückel theory, to rationalise the experimental steady-state voltammetry of two aqueous redox couples: hexaammineruthenium ([Ru(NH3)6]3+/[Ru(NH3)6]2+) and hexachloroiridate ([IrCl6]2−/[IrCl6]3−) (each with varying levels of KCl supporting electrolyte). This investigation provides evidence for ion pairing between [IrCl6]2−/[IrCl6]3− and K+ from the supporting electrolyte. No observable ion pairing occurs between [Ru(NH3)6]3+/[Ru(NH3)6]2+ and Cl−.

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来源期刊

Physical Chemistry Chemical Physics

CiteScore: 5.5

自引率: 10.3%

年发文量: 3036

Physical Chemistry Chemical Physics (PCCP) is an international journal co-owned by 19 physical chemistry and physics societies from around the world. This journal publishes original, cutting-edge research in physical chemistry, chemical physics and biophysical chemistry. To be suitable for publication in PCCP, articles must include significant innovation and/or insight into physical chemistry; this is the most important criterion that reviewers and Editors will judge against when evaluating submissions. The journal has a broad scope and welcomes contributions spanning experiment, theory, computation and data science. Topical coverage includes spectroscopy, dynamics, kinetics, statistical mechanics, thermodynamics, electrochemistry, catalysis, surface science, quantum mechanics, quantum computing and machine learning. Interdisciplinary research areas such as polymers and soft matter, materials, nanoscience, energy, surfaces/interfaces, and biophysical chemistry are welcomed if they demonstrate significant innovation and/or insight into physical chemistry. Joined experimental/theoretical studies are particularly appreciated when complementary and based on up-to-date approaches.