Potential step, chronocoulometry

Determinations of rate constants for the catalytic process were carried out by double potential step chronocoulometry... 

Reconstruction of Au(lll) is observed in STM images as double rows separated from each other by 6.3 nm [335]. Some model calculations have been performed [362] to show that the energy difference of the reconstructed and unreconstructed Au(lll) is small. The effect of Triton X-100 on the reconstruction process of Au(lll) surface has been studied in chloride media [363] applying CV and double potential-step chronocoulometry. It has been found that adsorption of Triton X-100 stabilizes the reconstructed face of Au(lll). Hobara etal. [364] have used in situ STM to study reconstruction of Au(lll), following reductive desorption of 2-mercaptoethanesulfonic acid SAMs. 

Thallium UPD on Au(lll) has been studied, applying potential-step chronocoulometry and quartz crystal microbalance [482]. The UPD surface coverage increased with the increasing cathodic potential. At low coverage, the sublayer was not completely discharged, as it appeared from electrosorption valency. 

Indicators and Dyes Abdel-Hamid [154] has studied adsorption of phe-nolphthalein at a HMDE in aqueous buffer solutions containing 10% v/v ethanol, applying cychc voltammetry and double potential-step chronocoulometry. At pH =... 

Double potential step Chronocoulometry with current reversal... 

Potential-step chronocoulometry, see Chronocoulo-metry and Double potentia1-step chronocoulometry... 

To a large extent, the discovery and application of adsorption phenomena for the modification of electrode surfaces has been an empirical process with few highly systematic or fundamental studies being employed until recent years. For example, successful efforts to quantitate the adsorption phenomena at electrodes have recently been published [1-3]. These efforts utilized both double potential step chronocoulometry and thin-layer spectroelectrochemistry to characterize the deposition of the product of an electrochemical reaction. For redox systems in which there is product deposition, the mathematical treatment described permits the calculation of various thermodynamic and transport properties. Of more recent origin is the approach whereby modifiers are selected on the basis of known and desired properties and deliberately immobilized on an electrode surface to convert the properties of the surface from those of the electrode material to those of the immobilized substance. 

Jan. 20, 1927, Cleveland, Ohio, USA - Aug. 10, 2004, Raleigh, NC, USA) Osteryoung received his bachelor s education at Ohio University and his Ph.D. at the University of Illinois. He was professor and Chairman of the Chemistry Department at Colorado State University, a professor at the State University of New York at Buffalo and research professor and Chair of the Department of Chemistry of North Carolina State University. He published about 225 original scientific papers, and was especially known for his papers on double potential step -> chronocoulometry, -> square-wave voltammetry, and room-temperature molten salt electrochemistry. He also initiated computer-controlled electrochemical measurements, which helped in developing and optimizing - pulse voltammetry. He served as an Associate Editor for the journal Analytical Chemistry. 

After making an approximate estimate of the absolute potential difference y/ across the mercury/aqueous solution interphase, let us detennine the electrosorption valency of three mercury-supported thiol monolayers for which uM was measured by potential-step chronocoulometry. As already reported in Sec. IV.1, n-octadecanthiol... 

Double potential-step chronocoulometry [1,2,221] may be used similarly to DPSCA. The working curves now include the charge ratio —Qb/Qf, which takes the value 0.414 for a simple electron transfer reaction. The reductive cyclization of ethyl cinnamate (see Chapter 21) illustrates the use of the technique [226,227]. 

Figure 5.1.5 Response curve for double potential step chronocoulometry. Step waveform is similar to that in Figure 5.1.4a.

Fig. 3 Double potential step chronocoulometry, showing deduction of surface concentration of adsorbed species. See text for details.

The unknown value Q i can be eliminated by double-potential step chronocoulometry (see Fig. 82). At t the potential is stepped to its initial... 

An improvement upon the chronocoulometric method described above represents the technique reported by Foresti et al. [218]. According to their procedure the potential-step chronocoulometry has been shown to provide all quantitative information about the adsorption of organic surfactants which may be completely desorbed at experimentally accessible negative potentials. 

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