Influence of 1-butyl-3-methylimidazolium on the electron transfer kinetics associated with the [SVW11O40](3-/4-) (V-V/IV) and [SVW11O40](4-/5-) (W-VI/V) processes in dimethylformamide

摘要

Fourier transformed large amplitude alternating current voltammetry has been used to determine the heterogeneous electron-transfer kinetics (k(0) and alpha values) associated with the vanadium [SVW11O40](3-/4-) (V-V/IV) and tungsten [SVW11O40](4-/5-) (W-IV/V) processes at glassy carbon (GC), platinum (Pt), gold (Au) and boron-doped diamond (BDD) electrodes in dimethylformamide (DMF) containing 0.5 M 1-butyl-3-methylimidazolium hexafluorophosphate as the supporting electrolyte. In comparison with data reported previously in DMF containing 0.5 M tetrabutylammonium hexafluorophosphate, the k(0) values at Pt, Au and BDD electrodes, were found to be larger by a factor of 2 to 4 for the V-V/IV process and 10 to 100 fold for the W-IV/V process. At a GC electrode, the rate of the V-V/IV process was too fast to be measured under the experimental conditions used (frequency = 34 Hz) and k(0) for the W-IV/V process was found to be insensitive to the identity of the supporting electrolyte cation. The origins of these observations are considered in terms of contributions from ion-pairing, surface functional groups on the GC electrode, the double layer effect, and the inner-sphere nature of the W-IV/V process. (C) 2016 Elsevier B.V. All rights reserved.