A survey on the effect of ionic liquid on electrochemical behavior and electrocatalytic activity of a phosphomolybdic acid-ionic liquid-MWCNT–modified glassy carbon electrode.

The surface of a glassy carbon electrode modified with multi-walled carbon nanotubes (GCE/MWCNTs) was coated with a layer of phosphomolybdic acid (PMo12) and ionic liquid (n-dodecyl pyridinium hexafluorophosphate, [C12Py][PF6]). Cyclic voltammetry was performed to investigate the effect of [C12Py][PF6] on the electrochemical behavior of the prepared modified electrode, GCE/MWCNTs/[C12Py][PF6]-PMo12. The surface coverage and the rate constant of electron transfer for three redox pairs of the immobilized PMo12 were evaluated and compared with those obtained for GCE/MWCNTs/n-octyl pyridinium hexafluorophosphate ([C8Py][PF6])-PMo12 fabricated using [C8Py][PF6] in our previous study to find a correlation between the structure of ionic liquid and its effect. Thereafter, the electrocatalytic activity of GCE/MWCNTs/[C12Py][PF6]-PMo12 towards the reduction of nitrite, H2O2, iodate, bromate, chlorate, and periodate was investigated and the rate constant for the chemical reaction of each analyte with PMo12 at the electrode surface was calculated. The prepared electrode was then applied for the amperometric measurements of the mentioned analytes with the satisfactory electroanalytical characteristics. [ABSTRACT FROM AUTHOR]