Electrode surfaces carbon-based

Evidence that double-stranded DNA molecules are adsorbed in such a way that the helical axis becomes parallel to the electrode surface, the base-pairs being vertically oriented against the electrode surface [45] leads to the conclusion that the thickness of a monolayer of adsorbed DNA at the electrode surface is less than 2 nm. This fact has been applied to use DNA adsorbed at a glassy carbon electrode as an effective electron promoter enabling electron transfer via hopping conduction through electrode-/base-pair/cytochrome c [91]. 

Eriksson T, Andersson A. M., Bishop A. G., Gejke C., Gustafsson T, Thomas J. O. Surface Analysis of UMn204 Electrodes in Carbonate-Based Electrolytes, J. Electrochem. Soc. 2002, 149,A69-A78. 

Aurbach and Zaban have found that the lithium surface deposited on a nickel electrode in carbonate-based electrolytes is covered with Li COj, LiOH,... 

The structure and composition of the lithium surface layers in carbonate-based electrolytes have been studied extensively by many investigators [19-37], High reactivity of propylene carbonate (PC) to the bare lithium metal is expected, since its reduction on an ideal polarizable electrode takes place at much more positive potentials compared with THF and 2Me-THF [18]. Thevenin and Muller [29] found that the surface layer in LiC104/PC electrolyte is a mixture of solid Li2C03 and a... 

For example, the final heat treatment temperatures In the manufacture will produce different electrochemical properties, even with the same surface treatments (2-4) since the structure and electrical property of glassy carbon depends on the temperature, as Indicated by the single crystal TEM patterns and by measurement of temperature dependent conductivity (5-6). On the other hand. It Is also well established that the electrochemical properties of carbon-based electrodes are markedly affected by surface treatments. 

Electrochemical capacitors are power storage devices, whose performance is based on the charge accumulation from an electrolytic solution through electrostatic attraction by polarized electrodes. The capacitance of this system is directly proportional to the electrode surface, therefore carbons are very efficient for this application because of various possibilities of their modification and creation of a controlled pore size distribution [1-3]. The electrostatic attraction of ions takes place mainly in micropores, however, the presence of mesopores is necessary for efficient... 

One of the main problems in the development of air gas-diffusion electrodes for metal-air cells is to find active and stable catalysts for the electrochemical reduction of oxygen. Carbon-based catalysts are mostly used, because of their highly developed surface area and capability for adsorption of 02, suitable morphology, chemical stability, good electric conductivity and comparatively low price. 

CNTs offer an exciting possibility for developing ultrasensitive electrochemical biosensors because of their unique electrical properties and biocompatible nanostructures. Luong et al. have fabricated a glucose biosensor based on the immobilization of GOx on CNTs solubilized in 3-aminopropyltriethoxysilane (APTES). The as-prepared CNT-based biosensor using a carbon fiber has achieved a picoamperometric response current with the response time of less than 5 s and a detection limit of 5-10 pM [109], When Nation is used to solubilize CNTs and combine with platinum nanoparticles, it displays strong interactions with Pt nanoparticles to form a network that connects Pt nanoparticles to the electrode surface. The Pt-CNT nanohybrid-based glucose biosensor... 

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 elemental composition, oxidation state, and coordination environment of species on surfaces can be determined by X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES) techniques. Both techniques have a penetration depth of 5-20 atomic layers. Especially XPS is commonly used in characterization of electrocatalysts. One common example is the identification and quantification of surface functional groups such as nitrogen species found on carbon-based catalysts.26-29 Secondary Ion Mass spectrometry (SIMS) and Ion Scattering Spectroscopy are alternatives which are more surface sensitive. They can provide information about the surface composition as well as the chemical bonding information from molecular clusters and have been used in characterization of cathode electrodes.30,31 They can also be used for depth profiling purposes. The quantification of the information, however, is rather difficult.32... 

The nanostructured thin-film electrode was first developed at 3M Company by Debe et al. [40] and Debe [41], who prepared thin films of oriented crystalline organic whiskers on which Ft had been deposited. The film was then transferred to the membrane surface using a decal method, and a nanostructured thin-film catalyst-coated membrane was formed as shown in Figure 2.10. Interestingly, both the nanostructured thin-film (NSTF) catalyst and the CL are nonconventional. The latter contains no carbon or additional ionomer and is 20-30 times thinner than the conventional dispersed Pt/ carbon-based CL. In addition, the CL was more durable than conventional CCMs made from Pt/C and Nation ionomer [40]. 

In order to guarantee an efficient performance of the CNT-based electrochemical devices, attention has to be paid not only to CNT synthesis and purification but also to the way that the CNT electrode is built up. There have been many studies in the literature dealing with CNT dispersions either on conducting substrates or forming composites. In this subsection we will address the different carbon-nanotube deposition techniques and carbon-nanotube arrangements on different electrode surfaces. 

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