Substrate glassy-carbon

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]. 

Crousier et al. examined the role of hydrogen evolution in the process of deposition of Mo-Ni alloys on different substrates (glassy carbon, Ni and Pd). It was found that on carbon and Ni substrates, bright and smooth deposits were formed, while on Pd no alloy was formed. This observation was related to easy absorption and diffusion of atomic hydrogen into Pd, which prevented its availability for the alloy codeposition process. Hence, it was concluded that hydrogen plays an important role in the codeposition of the alloy. This conclusion of the authors is, however, not convincing. Firstly, it is known that hydrogen atoms can also permeate into Ni to some extent. Secondly, unsuccessful attempt to deposit Mo-Ni alloys on Pd may also be attributed, for example, to kinetic limitations. 

In addition, if the cathodic electrografting of diazonium compounds onto carbon substrates (glassy carbon, HOPG, carbon fibers, carbon nanotubes [16], carbon felts... 

By electrodeposition of CuInSe2 thin films on glassy carbon disk substrates in acidic (pH 2) baths of cupric ions and sodium citrate, under potentiostatic conditions [176], it was established that the formation of tetragonal chalcopyrite CIS is entirely prevalent in the deposition potential interval -0.7 to -0.9 V vs. SCE. Through analysis of potentiostatic current transients, it was concluded that electrocrystallization of the compound proceeds according to a 3D progressive nucleation-growth model with diffusion control. 

In electrocatalysis, the activated carbons, glassy carbon, and carbon black are the transitional forms used. Carbon black is the product of incomplete combustion or decomposition of organic compounds. The shape of its particles is close to spherical. They contain several carbon atom lattice fragments arranged without order. Various types of carbon black serve as substrates for metal catalysts, the properties of the carbon blacks themselves having a strong elfect on the catalytic activity of the combined catalysts thus obtained. 

For fundamental studies of nanoparticles in IRAS measurements, a very important issue is how to attach metal nanoparticles onto a conducting substrate without changing their physical and chemical properties. Recently, we have developed a new method for anchoring metallic nanoparticles on reflective substrates of gold and/or glassy carbon, which we have termed a temperature-induced deposition (TID) method [Stamenkovic et al., 2004]. A key advantage of this method is that the catalysts... 

At the next level of abstraction are measurements performed at a thin film of fuel cell catalyst immobilized on the surface of an inert substrate, such as glassy carbon (GC) or gold (Fig. 15.2c). Essentially, three versions of this approach have been described in the fiterature. In the first case (a porous electrode ), an ink containing catalyst and Nafion ionomer is spread onto an inert nonporous substrate [Gloaguen et al., 1994 Gamez et al., 1996 Kabbabi et al., 1994]. In the second case (a thin-fihn electrode ), the ink does not contain Nafion , but the latter is... 

Electrocatalysis employing Co complexes as catalysts may have the complex in solution, adsorbed onto the electrode surface, or covalently bound to the electrode surface. This is exemplified with some selected examples. Cobalt(I) coordinatively unsaturated complexes of 2,2 -dipyridine promote the electrochemical oxidation of organic halides, the apparent rate constant showing a first order dependence on substrate concentration.1398,1399 Catalytic reduction of dioxygen has been observed on a glassy carbon electrode to which a cobalt(III) macrocycle tetraamine complex has been adsorbed.1400,1401... 

Garcia-Monco Carra et al. [296] have described a hybrid mercury film electrode for the voltammetric analysis of copper (and lead) in acidified seawater. Mercury plating conditions for preparing a consistently reproducible mercury film electrode on a glassy carbon substrate in acid media are evaluated. It is found that a hybrid electrode , i.e., one preplated with mercury and then replated with mercury in situ with the sample, gives very reproducible results in the analysis of copper in seawater. Consistently reproducible electrode performance allows for the calculation of a cell constant and prediction of the slopes of standard addition plots, useful parameters in the study of copper speciation in seawater. 

Mart et al. [793] and Valenta et al. [794] have described two differential pulse ASV methods for the determination of cadmium, lead, and copper in arctic seawater. After a previous plating of the trace metals into a mercury film on a rotating electrode with a highly polished glassy carbon as substrate, they were stripped in the differential pulse mode. The plating was done in situ. 

The concept of thin films of a molecularly imprinted sol-gel polymer with specific binding sites for a target analyte is general and can be applied also to electrochemical sensors. For example, a sensor to detect parathion in aqueous solutions is based on films cast on glass substrates and on glassy carbon electrodes (Figure 6.14).12... 

Substrates DME = dropping mercury electrode FTO = fluorine-doped tin oxide G = graphite GC = glassy carbon GrC = graphic carbon ITO = indium tin oxide-coated glass SC = single crystals SS = stainless steel TCO = transparent conducting oxide VC = vitrious carbon. Miscellaneous ECALE = electrochemical atomic layer epitaxy ED = electrodeposition ML = monolayer RT = room temperature SMD = sequential monolayer deposition V = vacuum. 

Optical properties of the material are less critical for microchips hyphenated with MS than for devices with on-chip optical detection where low background absorption or fluorescence is mandatory. Thus, completely opaque polymers like glassy carbon or polyimide " can be used as microfabrication substrates. Furthermore, polymer microchips are of great interest because their potentially low manufacturing costs may allow them to be disposable. Methods used for the fabrication of plastic chips include laser ablation and molding methods. 

Glassy Carbon Immobilized porous Carbon Substrate Enzyme Support... 

The rotating disc electrode is constructed from a solid material, usually glassy carbon, platinum or gold. It is rotated at constant speed to maintain the hydrodynamic characteristics of the electrode-solution interface. The counter electrode and reference electrode are both stationary. A slow linear potential sweep is applied and the current response registered. Both oxidation and reduction processes can be examined. The curve of current response versus electrode potential is equivalent to a polarographic wave. The plateau current is proportional to substrate concentration and also depends on the rotation speed, which governs the substrate mass transport coefficient. The current-voltage response for a reversible process follows Equation 1.17. For an irreversible process this follows Equation 1.18 where the mass transfer coefficient is proportional to the square root of the disc rotation speed. 

The preparation of film electrodes Prussian blue films are usually prepared by cycling an electrode in a freshly prepared solution containing iron(III) and hexacyanoferrate(III) ions [70-72]. As substrate, mostly platinum is used, sometimes glassy carbon [73] is used, and very frequently ITO electrodes [74] are used because the latter are very useful for electrochromism studies. Similar procedures using solutions containing metal ions and hexacyanoferrate(III) have been used to deposit cobalt hexacyanoferrate [75] and chromium hexacyanoferrate [76, 77]. Crumbliss et al. reported a plasma deposition of iron species from a plasma containing iron pentacarbonyl and ethane, followed by electrochemical derivatization of the deposited iron sites with the help of hexacyanoferrate solutions [78]. 

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