Electrochemical tests cyclic voltammetry

In this chapter, two carbon-supported PtSn catalysts with core-shell nanostructure were designed and prepared to explore the effect of the nanostructure of PtSn nanoparticles on the performance of ethanol electro-oxidation. The physical (XRD, TEM, EDX, XPS) characterization was carried out to clarify the microstructure, the composition, and the chemical environment of nanoparticles. The electrochemical characterization, including cyclic voltammetry, chronoamperometry, of the two PtSn/C catalysts was conducted to characterize the electrochemical activities to ethanol oxidation. Finally, the performances of DEFCs with PtSn/C anode catalysts were tested. The microstmc-ture and composition of PtSn catalysts were correlated with their performance for ethanol electrooxidation. 

Reversibility. The first aspect we analyse with cyclic voltammetry is electrochemical reversibility . Table 6.3 above lists the simplest voltammetrically determined tests of reversibility. A system that fulfills each of these criteria is probably electro-reversible, while a system that does not fulfill one or more of the criteria is certainly not fully electro-reversible. The CV shown in Figure 6.13 is that of a fully electro-reversible couple in a single electron-transfer ( E ) reaction. 

An electrochemical sensor using an array microelectrode was tested for the detection of allergens such as mite and cedar pollen (Okochi et ah, 1999). Blood was used in the assay and the release of serotonin, a chemical mediator of allergic response, which is electrochemically oxidized at the potential around 300 mV, was monitored for electrochemical detection by cyclic voltammetry. 

As a consequence, in our laboratories in Qausthal, any newly delivered ionic liquid is first tested by cyclic voltammetry and in situ STM on Au(lll) thoroughly before it is used for fundamental studies. This approach is somewhat time-consuming and in part frustrating for the students, on the other hand it is currently the only chance to avoid misinterpretation of electrochemical experiments, especially with the in situ STM. This is one of the challenges in ionic liquids electrochemistry. 

Electrochemical studies have been performed with the alkylammonium intercalated VOx nanotubes139 as well as Mn intercalated VO nanotubes87 Cyclic voltammetry studies of alkylammonium-VO nanotubes showed a single reduction peak, which broadened on replacing she amine with Na wish an additional peak. Li ion reactivity has also been tested with Mn-VO nanotubes by reacting with rt-butyllithium, and found that -2 lithiums per V ion are consumed. Electrochemical Li intercalation of Mn-VO nanotubes show that 0.5 Li ions per V atom were intercalated above 2 V.87 This observation may be relevant to battery applications. 

Chronoamperometry is more sensitive than cyclic voltammetry to defects in the SAM and serves as a stringent test of electroactive SAM order and integrity [73, 89]. The linearity of the appropriate plot (e.g.. In i versus t for a one-electron process) confirms that a single electrochemical process is occurring in the electroactive SAM [23]. 

Presented experimental results suggest that application of herbicide-binding protein in sensor technology has a high potential. Several detection systems were tested in combination with D1 protein electrochemical (amperometry and cyclic voltammetry), optical (surface plasmon resonance and ellipsometty) and assays (ELISA and D1 protein- containing liposomes and DELFIA fluori-metric assay). The main mechanisms of D1 action are either on the ability of herbicides to replace the plastoquinone molecule in D1 protein and in this way change the electrochemical and optical... 

For example, carbon-supported magneli phase Ti407 was synthesized and characterized for ORR catalysts, and evaluated cyclic voltammetry (CV), RDE, and RRDE techniques in electrolyte solutions containing various concentrations of KOH. The electrochemical stability of the catalyst was also evaluated by cyclic voltammetry scans and chronopotentiometric tests. 

Electrochemical impedance tests usually investigate the interface between an electrode material and a solution (for example corrosion tests may investigate different coated metals in a salt solution, while battery/fuel cell tests may investigate different electrode materials in an electrolyte). Electrochemical impedance tests provide complementary information to that obtained from dc electrochemical techniques such as cyclic voltammetry, pulse voltammetry, ohmic drop analysis, and chronoamperometry. 

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