Ionic Liquid Carbon Paste Electrode Research Articles

Electrocatalytic oxidation of formaldehyde on nickel modified ionic liquid carbon paste electrode as a simple and efficient electrode

Ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide was used to fabricate a new ionic liquid/carbon paste electrode (IL/CPE). The general behavior of this electrode was characterized by electrochemical impedance spectroscopy, cyclic voltammetry, and scanning electron microscopy. Results showed that the IL plays an important role in improving the conductivity, reversibility, and electron transfer rate of the electrode. Nickel-modified ionic liquid/carbon paste electrode (Ni/IL/CPE) was also constructed by immersion of the IL/CPE in 1.0 M nickel sulfate solution. IL showed significant effect on the accumulation of nickel species on the surface of the electrode. The Ni/IL/CPE was applied successfully to highly efficient (current density of 16.5 mA cm−2) electrocatalytic oxidation of formaldehyde in alkaline medium. Cyclic voltammetry and chronoamperometry techniques indicated that this electrode displays a considerable electrocatalytic activity toward the oxidation of formaldehyde. The effects of different scan rates and formaldehyde concentrations on the electrocatalytic activity of this modified electrode were investigated. Finally, the rate constant for chemical reaction between formaldehyde and redox sites of the electrode was calculated.

The Electrochemical Properties of 12-Molybdophosphoric Acid Modified Ionic Liquid Carbon Paste Electrode

A [C8mim]3PMo12O40-modified ionic liquid carbon paste electrode ([C8mim]3PMo12O40-ILCPE, C8mim = 1-methyl-3-octylimidazolium) was successfully fabricated. Its electrochemical properties were carried out on the cyclic voltammograms. The results of the cyclic voltammograms indicated that [C8mim]3PMo12O40-ILCPE exhibited remarkable electrocatalytic activities toward the reduction of BrO3− and good stability. The value of Ipc was as a function with the concentration of bromate from 2 × 10−6 to 1 × 10−4 M, which indicated that the [C8mim]3PMo12O40-ILCPE can be a candidate for electrochemical sensor.

Electrocatalytic oxidation of dopamine at an ionic liquid modified carbon paste electrode and its analytical application

A room-temperature ionic liquid N-butylpyridinium hexafluorophosphate was used as a binder to construct an ionic liquid modified carbon paste electrode, which was characterized by scanning electron microscopy and electrochemical impedance spectroscopy. The ionic liquid carbon paste electrode (IL-CPE) showed enhanced electrochemical response and strong analytical activity towards the electrochemical oxidation of dopamine (DA). A pair of well-defined quasireversible redox peaks of DA appeared, with the redox peaks located at 215 mV (E (pa)) and 151 mV (E (pc)) (vs. the saturated calomel electrode, SCE) in pH 6.0 phosphate buffer solution. The formal potential (E (0')) was calculated as 183 mV (vs. SCE) and the peak-to-peak separation as 64 mV. The electrochemical behavior of DA on the IL-CPE was carefully investigated. Under the optimal conditions, the anodic peak currents increased linearly with the concentration of DA in the range 1.0 x 10(-6)-8.0 x 10(-4) mol/L and the detection limit was calculated as 7.0 x 10(-7) mol/L (3sigma). The interferences of foreign substances were investigated and the proposed method was successfully applied to the determination of DA injection samples. The IL-CPE fabricated was sensitive, selective and showed good ability to distinguish the coexisting ascorbic acid and uric acid.