Double potential step chronoamperometry at a microband electrode: Theory and experiment

Abstract

Numerical simulation is used to characterise double potential step chronoamperometry at a microband electrode for a simple redox process, A + e − ⇋ B, under conditions of full support such that diffusion is the only active form of mass transport. The method is shown to be highly sensitive for the measurement of the diffusion coefficients of both A and B, and is applied to the one electron oxidation of decamethylferrocene (DMFc), DMFc − e − ⇋ DMFc + , in the room temperature ionic liquid 1-propyl-3-methylimidazolium bistrifluoromethylsulfonylimide.Theory and experiment are seen to be in excellent agreement and the following values of the diffusion coefficients were measured at 298 K: D DMFc = 2.50 × 10 −7 cm 2 s −1 and D DMFc + = 9.50 × 10 −8 cm 2 s −1 .

One-Electron Reduction of 2-Nitrotoluene, Nitrocyclopentane, and 1-Nitrobutane in Room Temperature Ionic Liquids: A Comparative Study of Butler–Volmer and Symmetric Marcus–Hush Theories Using Microdisk Electrodes

“…The mass transport equation and boundary conditions must be discretized in space and time to be solved numerically. For double-step chronoamperometry, the same grid as used in previous simulation studies is used . In this grid, an initial time point τ 0 is defined as 0.…”

“…For double-step chronoamperometry, the same grid as used in previous simulation studies is used. 41 In this grid, an initial time point τ 0 is defined as 0. The discrete time points then increase uniformly up to some defined time τ c , after which the grid expands:…”

Electrochemical Faradaic Spectroscopy

“…Commonly, it is conducted by stepping the electrode potential from a value at which no faradaic reaction occurs to a potential at which the surface concentration of the electroactive reactant is effectively zero, i. e., the Cottrell experiment. In the overall current response, the faradaic and charging currents can be easily separated, being the major advantage of the technique . Hence, the basis of all potential‐controlled electrochemical techniques is the measurement of the current after defined time interval in the applied potential sequence.…”