Glassy carbon electrode surfaces

Figure 3. Cyclic voltammograms of ascorbic acid at a freshly polished, active (a) and a deactivated (b) glassy carbon electrode surface. See text for details.

C.H. Lei and J.Q. Deng, Hydrogen peroxide sensor based on coimmobilized methylene green and horseradish peroxidase in the same montonorillonite-modified bovine serum albumin-glutaraldehyde matrix on a glassy carbon electrode surface. Anal. Chem. 68, 3344—3349 (1996). 

The oxidized forms of these two sandwich-type POMs are stable from pH 3 to at least pH 7. Their characterization by cyclic voltammetry revealed the stepwise reduction of the Gu " " centers within the POMs, before Gu" deposition on the glassy carbon electrode surface [115]. Phenomena are described mainly for the P-derivative and are the same for the As-analog. 

Other Substrates Deposition of cadmium was also studied on Bi, Sn and Pb [303], Ni [304], reticulated vitreous carbon [305], Ti [306], and indium tin oxide [307]. UPD of Cd on tellurium results in CdTe formation [270, 308]. Electrodes coated with conducting polymers were also used to deposit cadmium electrochemi-cally. In the case of polyaniline, the metal reduction potential corresponds to the neutral (nonconducting) state of the polymer, therefore cadmium was found to deposit on the substrate-glassy carbon electrode surface, in the open pores of the polymer film [309, 310]. 

Cyclic voltammetry was carried out in the presence of penta- and hexacyano-ferrate complexes in order to probe the homogeneity and conductivity of the TRPyPz/CuTSPc films (125), (Fig. 36). When the potentials are scanned from 0.40 to 1.2 V in the presence of [Fe (CN)6] and [Fe CN)5(NH3)] complexes, no electrochemical response was observed at their normal redox potentials (i.e., 0.42 and 0.33 V), respectively. However, a rather sharp and intense anodic peak appears at the onset of the broad oxidation wave, 0.70 V. The current intensity of this electrochemical process is proportional to the square root of the scan rate, as expected for a diffusion-controlled oxidation reaction at the modified electrode surface. The results are consistent with an electrochemical process mediated by the porphyrazine film, which act as a physical barrier for the approach of the cyanoferrate complexes from the glassy carbon electrode surface. 

Figure 6. SEM image of glassy carbon electrode surface modified with gold nanoparticles prepared with the seed-mediated growth approach. Reproduced from [32], copyright 2007, with permission from the Japan Society for Analytical Chemistry.

Schreurs, J., Van den Berg, J., Wonders, A., Barendrecht, E., Characterization of a Glassy-Carbon-Electrode Surface Pretreated with rf-Plasma , Reel. Thav. Chim. Pays-Bas 103 (1984) 251-259. 

FIGURE 11.16 Schematic diagram of the setup of a micro electropolymerization cell. A drop of solution was placed on the glassy carbon electrode surface. 

Figure 5.12 Cyclic vcitammograms of Fe-N/C with 5 wt% coated on a glassy carbon electrode surface, recorded in a N2-purged 0.5 M H2SO4 solution. Fe-N/C loading 150 [xg cm potential scan rate 50 mV s". "...

POM 4- NADPH) is the current for the reduction of the POM in the presence of NADPH and is the corresponding diffusion current for the POM alone. In the present experiments, CAT values of 403 and 730% were calculated for y = 10 and y = 20 respectively at 4-308 mV vs. SCE. Figure 35(b) shows the direct NADPH oxidation wave on the glassy carbon electrode surface and the rising section of the catalytic wave for y = 20 in the same pH 8 medium. It is clear from this figure that no direct oxidation of NADPH is observed in this potential domain explored in Fig. 35(a). Furthermore, the substantial improvement in potential brought about... 

C-H oxidation (150). The Jacobsen s ligand has been used for the modification of the manganese exchanged Al-MCM-41, that is the immobilized catalyst has been investigated in epoxidation of styrene (151). Chiral manganese-Schiff base complexes were immobilized on a glassy carbon electrode surface (152). Enan-tioselective epoxidation reactions were also catalyzed with Mn(III) complexes of chiral porphirines (97,153). 

Investigations based on carbon paste electrodes (modified with octadecylamine or stearic acid to provide amine or carboxylic acid functionalities) were quickly abandoned owing to problems with day-to-day reproducibility and precision. Regeneration methods used to denature the double-stranded DNA on the nucleic acid functionalised glassy-carbon electrode surfaces were found to destroy the carbon paste electrodes. Regeneration of sensors based on glassy carbon electrodes was reported to be effectively achieved by treatment with hot (100°C) distilled water for 10 minutes and that no significant peak current deterioration was observed to... 

Cyclic voltammogram of mesoporous carbon coated glassy carbon electrode surface (0.2 cm ), recorded in N2-purged 0.5 M H2SO4 solution at 23°C and ambient pressure. Carbon loading = 100 ]ig.cm . Potential scan rate = 50 mV.S". Source Nicholson, R. S. and I. Shain. 1964. Analytical Chemistry, 36, 706-723. With permission.)... 

Louault, C., M. D Amours, and D. Belanger. The electrochemical grafting of a mixture of substituted phenyl groups at a glassy carbon electrode surface. Chem. Phys. Chem. 

Kanazawa, A., T. Daisaku, T. Okajima, S. Uchiyama, S. Kawauchi, and T. Ohsaka. Characterization by electrochemical and X-ray photoelectron spectroscopic measurements and quantum chemical calculations of N-containing functional groups introduced onto glassy carbon electrode surfaces by electrooxidation of a carbamate salt in aqueous solutions. Langmuir 30, 2014 5297-530. 

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