The pH-dependence of oxygen reduction on quinone-modified glassy carbon electrodes

Electrocatalytic Reduction of Oxygen at Anthraquinonedisulfonate/Polypyrrole Composite Film Modified Electrodes and Its Application to the Electrochemical Oxidation of Azo Dye

“…While the corresponding ORR peak potentials and peak currents are different in various pH solutions. This result can be related to the different formal potentials of the doping AQDS in various pH media [15,18,19]. The oxygen reduction potentials shift to more positive values with the increasing pH value (À 0.65, À 0.60 and À 0.52 V for pH 3.0, 4.0 and 6.0, respectively), which indicate that the pH 6.0 solution seems to be a more suitable medium for ORR electrocatalyzed by the AQDS/PPy composite film.…”

“…It is well known that the cathode material and solution pH play important roles on ORR [15,19,32]. Figure 1 shows the cyclic voltammograms (CVs) of oxygen reduction in various pH O 2 -saturated solutions at the AQDS/PPy composite film modified GC RDE.…”

“…The well-known method for the preparation of such electrodes concerns the immobilization of materials such as metal catalysts [3], metal porphyrins [4], metal phthalocyanine complexes [5 -7], heteropolyanions [8], and quinones [9 -19] that act as electrocatalysts in the reduction of oxygen on the electrode surface. By contrast with other catalysts, quinones mainly support the twoelectron reduction of oxygen [19]. In addition, due to the high surface area, high electronic conductivity and useful mechanical properties of the polymer film, conducting polymer modified electrodes have characteristics in transporting electron and ions through the polymer film and mediating redox of the solution species.…”

Electrocatalytic Reduction of Free Chlorine at an N,N-Diethvlaniline-grafted Carbon Electrode for Improved Sensitivity in Amperometric Detection

“…An increase in the background current, however, was also observed at potentials more negative than -0.4 V due to the dissolved oxygen. 16 The detection limit was reproducible to ca. 1 × 10 -6 M NaClO for three separate measurements with an applied potential of -0.3 V. At ~5 × 10 -3 M, the amperometric response showed a considerable decay within 10 s which deviated from a linear relationship.…”

Anthraquinone modification of microporous carbide derived carbon films for on-chip micro-supercapacitors applications

“…After the departure of loosely attached AQ molecules upon the first 50 cycles, the second fade in faradic contribution of AQ after 300 cycles could be due to the repeated formation of quinone dianions upon cycling. It was proposed that the quinone dianions induced from the two electron process occurring in very basic media can endure repulsion interactions toward the negatively charged carbon surface and dissolve in the alkaline electrolyte [60]. This could explain the loss of faradic response recorded after the 300th cycle, as electrostatic repulsion should be exacerbated in such confined micropores.…”