Double 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. 

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... 

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. 

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... 

Potential Step Chronocoulometry Double Potential Step Chronocoulometry ... 

Engelman EE, Evans DH (1992) Explicit finite-difference digital simulation of the effects of rate-controlled product adsorption or deposition in double-potential-step chronocoulometry. J Electroanal Chem 331 739-749... 

Anson, F.C., Christie, J.H., and Osteryoung, R.A. (1969) A study of the adsorption of cadmium (II) on mercury from thiocyanide solutions by double potential-step chronocoulometry. J. ElectroanaL Chem., 13 (4), 343—353. 

A nitrate sensor has been also reported by Kim et al.." This sensor uses a simple electrochemical system composed of a silver sensing electrode, a silver oxide reference electrode, and a platinum counter electrode in 0.01 M NaOH concentrically distributed electrolyte. These micro-electrodes are microfabricated on a silicon substrate, providing an electrochemical microcell ion which a single microfluidic channel is used to deliver the reagents. Nitrate concentration is detected using double-potential step chronocoulometry in which the current accrued from nitrate reduction to nitrite is integrated. 

Kim D, Goldberg IB, Judy JW (2009) Microfabricated electrochemical nitrate sensor using double-potential-step chronocoulometry. Sens Actuat B 135 618-624... 

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