Coulometry on the Voltammetric Timescale: Microdisk Potential‐Step Chronoamperometry in Aprotic Solvents Reliably Measures the Number of Electrons Transferred in an Electrode Process Simultaneously with the Diffusion Coefficients of the Electroactive Species

Abstract

Microdisk, single potential-step chronoamperometry, is applied to a range of organic substrates in the aprotic solvents tetrahydrofuran, propylene carbonate, acetonitrile and the room temperature ionic liquid [C 4 dmim][N(Tf) 2 ]. Fitting of the chronoamperometric transients was achieved using the Shoup and Szabo method [3]. Accurate values for the diffusion coefficients, D, and the number of electron(s) transferred, n, in the electrode process have been simultaneously and consistently obtained. This method is shown to be generally applicable and reliable for the determination of the number of electrons transferred in faradaic processes uncomplicated by relatively slow coupled homogeneous kinetics. Since the experiment is conducted essentially on typical voltammetric timescales it can be commended as a complementary technique for classical coulometry which is only possible on much longer timescales. The chronoamperometric method is therefore likely to be of greater relevance to the interpretation of voltammetric data.

Voltammetry at porous electrodes: A theoretical study

“…[25][26][27] In our model of the porous electrode by hypothesis we decouple the current response from the interior of the spheres from that of the overall "disc".…”

The electrochemical reduction of the purines guanine and adenine at platinum electrodes in several room temperature ionic liquids

“…Excellent fitting was observed and a diffusion coefficient (D), of 5.2 ± 1.15 × 10 −8 cm 2 s −1 and concentration (C) of 94.67 ± 0.17 mM was obtained. Thus chronoamperometric data suggest that the number of electrons involved in the reduction of guanine is one electron per molecule (0.947 ± 0.05 electrons) [37].…”

Chronoamperometric determination of diffusion coefficients of ferrocene in ionic liquids mixed with CO2 at high pressures

“…In the present work, we apply the electrochemical chronoamperometry using a disk electrode, which can allow the precise measurements of diffusion coefficients of electroactive species in solution by the well-established experimental treatment [21][22][23][24][25], because ILs have sufficiently high electrical conductivities that remarkably increased with increasing CO 2 addition as previously reported [17]. [26][27][28][29] have examined the effects of gases on cyclic voltammograms and chronoamperograms of electroactive solutes in ILs at ambient pressures, and also van Eldik and coworkers [30,31] have made efforts in high-pressure electrochemistry in ILs (regardless of gases).…”