Investigations on the Kinetics of Electron Transfer Reactions in Magnetic Fields

Abstract

There is a controversial debate if a magnetic field can influence the rate of electron transfer (ET) reactions. In this paper, we report kinetic measurements of the ET rate constants for the redox couples [IrCl6]2-/[IrCl6]3-, [Fe(CN)6]3-/[Fe(CN)6]4-, and [Fe(H2O)6]3+/[Fe(H2O)6]2+ in magnetic fields up to 1 T. To reduce effects arising from magnetically induced mass transport (magnetohydrodynamic effect), disk microelectrodes with a diameter of 50 microm were used in potentiodynamic (cyclic and linear sweep voltammetry) and in electrochemical impedance spectroscopy experiments. None of the investigated redox couples showed a magnetic field effect on the ET rate constant.

A study of external magnetic-field effects on nickel–iron alloy electrodeposition, based on linear and non-linear differential AC electrochemical response measurements

“…It can be noticed that both Re(Z) and Im(Z) are responsive to B in the investigated frequency range. It is worth noting that the effect of B tends to decrease with frequency: this is coherent with the recognised scenario, according to which magnetic-field effects tend to affect the mass transport rather than the charge transfer [52,53]. In fact, the impedance response at lower frequencies is more sensitive to mass transport, while at higher frequencies, charge transfer processes dominate.…”

Magnetic field effects on the initial stages of electrodeposition processes

“…On the other hand, there are only few papers [12][13][14] which investigated the initial stages of electrocrystallization, such as nucleation and underpotential deposition (UPD) processes in the B field, because the general tenet is that the chief magnetic field effects are related to masstransport (MHD convection) and that molecular processes are hardly affected [15][16][17][18]. In our previous work [19], the surface morphology at the initial stage of Cu deposition was investigated by AFM.…”

Retarding the corrosion of iron by inhomogeneous magnetic fields

“…The charge transfer steps of electrochemical reactions were reported to be independent on applied magnetic fields and experimentally observed magnetic field effects on charge transfer controlled anodic dissolution reactions were explained by a magnetic field effect on the surface pH value . But in a low concentrated electrolyte, as it is used in the present study, already under free corrosion conditions the mass transfer in the electrolyte governs the electrode behavior .…”