Electrode compound

The electrochemical mechanism of cupric sulphate activating sphalerite has been studied. The measured cyclic voltammogram curves in aqueous solution at different pH with sphalerite compound electrode are shown as solid lines in Fig. 6.1. 

The cyclic voltammogram for sphalerite compound electrode changes greatly in aqueous solution with the CUSO4 concentration of 1.1 x 10 mol/L, which is shown as dotted lines in Fig. 6.2. It can be seen that compared with the oxidation properties of sphalerite, the oxidation properties of those surface produets change after sphalerite is activated by CUSO4. In the term of initial oxidation potential, the surface products are superior to sphalerite in oxidation. 

Figure 6.2 Cyclic voltammetric curves for sphalerite compound electrode in buffer solution with different pH at 293K, KNO3 concentration of 0.5 mol/L and sweep rate of 20 mV/s...

Compound electrodes with a species-selective electrode enclosed by a membrane that is able to separate that species from others or that generates the species in a chemical reaction. 

Numerous ingenious compound electrodes using enzymes have been built.29 These devices contain a conventional electrode coated with an enzyme that catalyzes a reaction of the analyte. The product of the reaction is detected by the electrode. 

Explain the principle of operation of ion-selective electrodes. How does a compound electrode differ from a simple ion-selective electrode ... 

Standard addition. A particular COz compound electrode like the one in Figure 15-22 obeys the equation E = constant — [p/ T (In 10)/2F log[C02], where R is the gas constant, T is temperature (303.15 K), F is the Faraday constant, and P = 0.933 (measured from a calibration curve). [C02] represents all forms of dissolved carbon dioxide at the pH of the experiment, which was 5.0. Standard additions of volume Vs containing a standard concentration cs = 0.020 0 M NaHC03 were made to an unknown solution whose initial volume was V0 = 55.0 mL. 

Compound Electrode material Substance produced Amount produced Substance produced Amount produced... 

No. Compound Electrode material Aqueous electrolyte AG ads solution (M) kcal mol 1 Estimated" orientation (charge on surface) Assumed interaction... 

In the above section, various dissolution mechanisms for III-V compound electrodes were proposed on the basis of stabilization studies. There is evidently a need for confirmation of these mechanisms from independent data. Such confirmation can be obtained by quantitatively studying the enhancement of the anodic dark current at n-type electrodes, caused by hole injection. Although, as mentioned in Sec. 2.1, this effect has been known for many years, only recently was it realized [41] that the relationship between the additional anodic current density 4 and the cathodic hole injection current density constitutes a powerful probe for in-... 

During the 30 years from 1970, the potential distribution at many semiconductor electrodes has been studied. In the early stage of semiconductor electrochemistry primarily germanium and silicon electrodes were investigated because well-defined single crystals were available. It turned out much later that very important basic information had been obtained, especially with intrinsic germanium electrodes (ng = po), as will be shown below. In the following, Ge, Si and compound electrodes will be treated separately. 

The change of guest atom composition in the matrix atom is accompanied by an intercalation reaction within the same crystal structure of the matrix atom. The characteristic feature of intercalation/deintercalation is, first, that the reaction proceeds not only at the interface between electrolyte and host intercalation compound electrode but also even in the interior of the electrode. 

In view of the numerous oxidation states, an extensive oxidation-reduction chemistry of technetium is expected. Polarographic reductions of pcrtechnetate in aqueous and in non-aqueous solutions, supplemented by coulometric and cyclic voltammetric measurements, were conducted to study the electrochemical behavior of technetium, to identify some oxidation stales and to synthesize new technetium compounds. Electrode reactions frequently proved to be irreversible and therefore not adequate for calculating thermodynamic data. The electrochemistry of technetium is reported in detail in several review articles [11-13]. 

The electronegativity model has been used successfully on metal/organic semiconductor interfaces, and shown to give a satisfactory description of the interface barrier formation. As electronegativity is defined only for elements it is of interest to investigate if the electronegativity model can be extended to compound electrodes such as indium tin oxide (ITO), which... 

There are only two requirements for the compounds and materials to be used by VIM They should be highly insoluble in the electrolyte solution used and they must possess electroactivity, i.e., the ability to be either oxidized or reduced in the accessible potential window of the experiment. Most importantly, there is no restriction with respect to the electronic conductivity. Even insulators such as white phosphoms can be studied, because the electrochemical reaction which can take place at the three-phase boundary compound-electrode-solution can often deliver sufficient charge to give measurable currents. One can easily distinguish three different kinds of compounds, those which are not electroactive, those which are irreversibly destroyed in the electrochemical reactions, and those which can be reversibly reduced and oxidized. The latter compounds are characterized by possessing the ability to exchange electrons with the electrode and ions with the solution. This ability requires solid compounds that can house ions through features of their crystal structure, e.g., channels or interlayers. 

ELSA compound electrode medium iaige diameter potential... 

C. Silver-Silver Chloride Electrode. Although the mercury-mercury compound electrodes are useful, the toxicity of mercury compounds is a concern with regard to their use and disposal. This is overcome by using silver-silver chloride electrodes. The electrode reaction responsible for the potential of the Ag/AgCl electrode is ... 

E. Box 6-1 discussed nitrogen species found in a saltwater aquarium. Now we consider the measurement of ammonia in the fishtank, using an ammonia-selective compound electrode. The procedure is to mix 100.0 mL of unknown or standard... 

Beck, F. Csizi, G. (1971) Lead dioxide-titanium compound electrodes. German Patent 2,119,570 April 22, 1971. 

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