Glassy carbon disk electrodes

The electrodeposition of tellurium and silver has been investigated in dilute aqueous solutions of tellurous acid and Ag " ions (concentrations in the order of 10 to 10 " M) in 0.1 M HCIO4 [164], In particular, cyclic voltammetry experiments were conducted with rotating glassy carbon disk electrodes in baths with various concentration ratios of Ag(I) and Te(IV) precursors, and their outcome was discussed in terms of the voltammetric features. For a Ag(I)/Te(IV) ratio close to 0.8, formation of quasi pure silver telluride, Ag2Te, was reported. The authors, based on their measurements and on account of thermodynamic predictions, assumed that silver is deposited first on the electrode (Ag" + e Ag), and then Te(IV) is reduced on the previous silver deposit with formation of Ag2Te according to the reaction... 

Fig. 2 Cyclic voltammograms recorded at a glassy carbon disk electrode (diameter = 1mm) at a sweep rate of lVs-1 in 0.2 M Bu4NPF6/THF for Zn-reduced solutions of...

Fig. 54. Cyclic voltammogram of H SiW O recorded at conventional size glassy carbon disk electrode, (a) Single-crystal sample (b) 4 mM H4SiW1204o in 0.5 M H2SO4. (From Ref. 269.)...

Figure 23.9 Trace analysis of a metal (M) analyte in the presence of surfactants (S) using the vertically active and horizontally passive aligned nanowires. Such adaptive operation leads to opening and closing of the surface to allow measurement and protection of the transducer between measurements. Also shown are the optical images (top view) of the glassy-carbon disk electrode covered with the vertically (left) and horizontally (right) aligned nanowires.47 (Reprinted with permission from R. Laocharoensuk et al.,...

In a rotated ring-disk electrode experiment where the disk is controlled at +2.6 V versus SCE for the oxidation of HOOH and the ring electrode is controlled at -1.4 V versus SCE for the reduction of the oxidation products from HOOH, the observed collection efficiency (N = /r//d) is 0.384. This is slightly less than the theoretical value of 0.418 for the electrode. The products from HOOH oxidation at the glassy-carbon disk electrode (ED, + 2.6 V vs. SCE) can be characterized at the ring by scanning its potential from +1.0 to... 

Example 2.1 The reversible oxidation of dopamine (DA) is a 2e process. A cyclic voltammetric anodic peak current of 2.2 pA is observed for a 0.4-mM solution of dopamine in phosphate buffer at a glassy carbon disk electrode of 2.6 mm2 with a scan rate of 25mV/s. What will ip be for v = lOOmV/s and 1.2mM DA ... 

Fig. 20.1. Cyclic voltammograms at 5 mV for 1 pM Fc containing MPC (average 9 Fc per cluster) in 0.1 M tetrabuthylammonium perchlorate (Bu4CI04)/CH2Cl2 at a stationary (- -) and rotated (—, 1600 rpm) glassy carbon disk electrode. (Adapted from J. Am. Chem. Soc., 1996, 118, 4212).

In a cyclic voltammogram recorded with a glassy carbon disk electrode modified by the crosslinked Co-PEI complex film, the uncatalyzed reduction of oxygen was observed at potentials lower than -0.3 V. As such, a significant increase in the current magnitude was noted for the electrode surface modified with the thin Co-PEI membrane under an air atmosphere due to the oxygen enrichment from the aqueous phase. 

Figure 13.4 shows cyclic voltaimnograms on a glassy carbon disk electrode (for oxidation) and on a platinum disk electrode (for reduction) with/without Phoslyte between 0.0 V and 5.2 V versus Li/LP. Both electrolytes were electrochemically stable within 0.3-5.0 V. Addition of Phoslyte did not affect the electrochemical voltage window of base electrolyte. 

Figure 4.6 (A) Current-potential curves for 02-saturated 1.0 M NaOH solution at a polished glassy carbon disk electrode, T= 298 K potential scan rate,...

Figure 7.16 Current—potential curves (bottom) of the carbon-supported nanosized Pt and PtNi alloy catalysts coated on a glassy carbon disk electrode in Oa-satu-rated 0.5 M HCIO4 solution (scan rate of 5 mV s and rotating speed of 2000 rpm) and the corresponding ring currents (Pt at 1.2 V vs RHE) data for the hydrogen peroxide production (upper) on Pt/C, Pt Ni(2 1)/C and Pt Ni(1 1)/C systems. Reprinted with permission from Ref. 55.

Fig. I. Cyclic voltammograms (I-a, Il-a, Ill-a) at a scan rate of 100 mV s" and RDE voltammograms (I-b, Il-b, Ill-b, c, d) at an electrode rotation rate of 1000 rpm, and a scan rate of 10 mV s on a glassy carbon disk electrode with 0.2 M Na2S04 at 25°C. I for 1 mM -complex 3 at pH 10.0. II for 1 mM Ni -complex at pH 7.3 (Tris buffer) curve a and b for Fe -complex 3, curve c for Fe -complex 7 (aeration product of Fe -complex 3), curve d for free ligand 1 no further oxidation wave was seen up to -f 0.5 V vs. SCE.

Fig. 24.4 Cyclic voltammograms for Pt/Vulcan electrocatalyst deposited on a glassy carbon disk electrode in 0.1 M HCIO4 thermostated at 25 °C...

Fig. 18 Cyclic voltammetry of the catalysis of glucose oxidation at a glassy carbon disk electrode coated with 10 glucose oxidase monolayers in the presence of glucose and ferrocene methanol in pH 8.0 phosphate buffer (ionic strength, 0.1 M). Temperature 25 °C.

Figure 8 - (a) Cyclic voltammogram (scan rate 50 mV s"i, 25 2°C), reduction of 0.5 mol L"i 3-bromo-benzo-phenone in DMF (0.1 M TRAP), 3-mm-diameter glassy carbon disk electrode. Sonovoltammograms obtained with 25 W cm"2 power and (b) 27, (c) 15, (d) 8 mm horn-to-electrode distance... 

The monomer, aniline boronic acid (6a in Scheme 17.4) is prepared in a pH 7.4 phosphate buffer saline (PBS) solution, and later 0.5 M HCl is added to bring its pH to 5. Potentiodynamic polymerization of the monomer is carried out on a glassy carbon disk electrode between. 1 to 1.0 V at the rate of 100 mV s until... 

The electrochemical active surface area (EASA) of fuel cell Pt-based catalysts could be measured by the electrochemical hydrogen adsorption/desorption method. For carbon supported Pt, Pt alloy, and other noble metals catalysts, the real surface area can be measured by the cyclic voltammetry method [55-59], which is based on the formation of a hydrogen monolayer electrochemically adsorbed on the catalyst s surface. Generally, the electrode for measurement is prepared by dropping catalyst ink on the surface of smooth platinum or glassy carbon substrate (e.g, a glassy carbon disk electrode or platinum disk electrode), followed by drying to form a catalyst film on the substrate. The catalyst ink is composed of catalyst powder, adhesive material (e.g., Nafion solution), and solvent. 

Morphology of the CL surface Dispersion of Pt/C catalyst on glassy carbon disk electrode Characterize Pt content through cross-section of the MEA Investigate Pt content in Pt/C catalyst... 

A simple and quick method in FIA using a glassy carbon disk electrode modified with a molybdenum oxide film has been proposed for the quantification of iodate in commercial salt samples [48]. In this study, the film actuated as a catalytic agent in the reduction of iodate and a linear response was observed (from 1.0 x 10 to 1.0 x 10 mol r ). Other amperometric method coupled to FIA exploring the electrochemical reduction of iodate was also described [49]. Here, the authors used a more favorable working potential (+0.2 V vs. Ag/AgCl) in the presence of a solution of 1.0% w/v NaCl, 0.02% w/v KI, and 0.1 mol 1 HCl as carrier. 

The electrochemical oxidation of ALT in 10 % methanol + 90 % IM HC104 aqueous solution on a glassy carbon disk electrode has been studied using CV and SWV (Molina, Zon Fernandez, 2002). From voltammetric responses, a complex reaction mechanism could be... 

Figure 6. Cyclic voltammograms obtained with glucose oxidase modified with 14 1 enzyme-bound ruthenium pentaammine functions without glucose and at 20 mM glucose concentation. 3 mm diameter glassy carbon disk electrodes scan rate 1 mVs. ...

Conventional 3-electrode cells, commercial potentiostats with external feedback IR compensation, and procedures similar to those described previously were used for electrochemical experiments. Working electrodes were a PARC Model 9323 hanging-drop-mercury electrode (HDME, A = 0.019 cm ) or a highly polished glassy carbon disk electrode (GCE, A = 0.071 cm ). A Pt wire served as the counter electrode and the reference was a saturated calomel electrode (SCE). For the HDME, a fresh Hg drop was used for each experiment. A polishing method described previously was used for GCE " and was repeated prior to each voltammetric scan. Area of the GCE was estimated electrochemicaly by using the Randles-Sevcik equation and CV peak for the oxidation of ferrocene in acetonitrile (D = 2.4 X 10 cm s i). Experiments in all CTAB solutions were thermo-statted at 30.0 0.1 C for SDS the temperature was usually 25.0 0.1 C. 

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