Oxidation galvanostatic

The complex trans-[Cun(hfac)2(TTF—CH=CH—py)2](BF4)2-2CH2Cl2 was obtained after 1 week of galvanostatic oxidation of Cun(hfac)2(TTF CH=CH py)2 [61]. The molecular structure of the copper complex is identical to its neutral form. There is one TTF CH=CH py molecule per BF4 and one dichloromethane solvent molecule. The copper is located at the center of a centrosymetric-distorted octahedron two TTF CH=CH py ligands in trans- conformation are bonded to Cun by the nitrogen atoms of the pyridyl rings. From the stoichiometry, the charge distribution corresponds to fully oxidized TTF CH=CH—py+" radical units. 

In the presence of Pb(II) ions in sulfuric acid, potential oscillations have been observed for galvanostatic oxidation of hydrogen on platinum electrode [129]. This behavior has been attributed to ad-sorption/oxidation/desorption processes of lead on the platinum surface. Lead at high values of coverage is oxidized to insoluble PbS04, which blocks the Pt surface. 

Aluminum underdeposited on gold electrodes from AICI3 + NaCl melts at 200-300 °C. The process has been studied [479] applying CV, potentiostatic deposition, and galvanostatic oxidation. The obtained deposits were characterized by electron microprobe analysis and glancing incidence by X-ray diffraction. 

Fig. 65. Spatiotemporal evolution of the potential at a Pt electrode during the galvanostatic oxidation of H2 in the presence of Cu2+ and Cl- ions after subtraction of the homogeneous oscillating part [64], (b) Temporal evolution of the total current. The first four oscillations correspond to the time interval shown in (a).

The influence of current density on both ICE and COD evolution with the specific electrical charge passed during the galvanostatic oxidation of a 5 mM 2-naphtol in 1M H2S04 at different current densities (119 — 476 A m-2) is shown in Fig. 1.9. As previously noted, an excellent agreement between the experimental and predicted values is observed. 

Yahnke et al 136) obtained spectra for CO adsorbed from solution onto a cormnercial platinum on carbon fuel cell electrode. The surface coverage was modified by galvanostatic oxidation in the NMR electrochemical cell, but the spectra were measured under open-cell conditions. At saturation coverage, the maximum of the line is at approximately 450 ppm below half that coverage, the maximum shifts to 330 ppm. The value at saturation agrees well with those in Fig. 41. 

For galvanostatic oxide growth (log i = const) the E field has to be constant resulting immediately in the proportionality ... 

Figure 13. (A) Sinusoidal, smaU-amplitude potential oscillations close to the onset of oscillations at low current densities during the galvanostatic oxidation of. (a) 50 //A/cm (b) 52.5 //A/cm (c) 60 //A/cm. (B) Large-amphtude relaxation oscillations close to the end of the oscillatory region at high current densities during the galvanostatic oxidation of H,. (a) 120 pA/cm (b) 200 pA/cm (c) 300 pA/cm (potential given vs. SHE). (After Krischer et...

Figure 16. Regions of different dynamic behaviors during the galvanostatic oxidation of H 2 in the current density-halide concentration plane. H, small harmonic oscillations MMO, mixed-mode oscillations (see Section 11.4) R, large-amplitude relaxation oscillations. (After Wolf etalJ )...

In a recent paper by Bolzan and Arvia, the oxygen evolution reaction (OER) was studied on different types of oxide-coated Pt electrodes in 1 mol dm H2SO4. The various oxide layers were obtained by various potential cychng and by galvanostatic oxidation. The experimental results were interpreted in terms of different oxide layer structure on the basis of the assumptions ... 

During the oxidation of formic acid and formaldehyde on platinum electrodes, an oscillatory behavior is frequently observed. " The surface poisoning species play a central role in the triggering of the oscillatory phenomena. Recent studies on formic acid and formaldehyde oxidation confirm this view. Inzelt and Kert sz reported that by the use of electrochemical quartz crystal microbalance technique (EQCM), the periodical accumulation and consumption of strongly bound species can be observed in the course of potential oscillation produced by the galvanostatic oxidation of formic acid. 

Figure 13. Variation of A and with potential in steady state and transient (x, 0.8 0, 0.32 A, 0.08 mA crn ) oxidation and i—V relation in steady state oxidation. (9,0)Galvanostatic oxidation transients potentiostatic steady state) oxi-...

Variation in electrode potential on open circuit after galvanostatic oxidation at 2.5 pA cm continuously increasing potentials (vs Hg/Hg2S04) [23]. 

The phase composition of the anodic layer formed during the galvanostatic oxidation of Pb at current density 2.5 mA cm has been investigated [120]. It is claimed that the metal surface is covered by a dense tet-PbO layer. With increase of the distance from the metal surface, formation of PbOx (1 < x < 2) and a-Pb02 commences, and in the outermost layers P-Pb02 is formed. The authors explain this sequence by diffusion of oxygen through the anodic layer [120]. 

Fig. 10 Time-resolved SEIRA spectra of the Pt electrode surface acquired during galvanostatic oxidation of formaldehyde with an applied current of 10 mA the time resolution was 80 ms. A spectrum of the Pt surface in 0.5 M H2SO4 before injecting formaldehyde was used as the reference. [Reprinted from ref 41 by permission of the American Chemical Society copyright 2007.]...

With the help of EQCN measurements, it has been proved that the accumulation and consumption of strongly bound species produces the potential oscillations in the course of galvanostatic oxidation of small organic compound, such as formic acid [27], Figure II.IO.11 shows the simultaneous changes of the potential and the... 

Figure 10. Galvanostatic oxidation curves for hydrocarbons adsorbed on platinum black electrodes at 25°C from 5N H2SO4 (1) C2H4, (2) C4H10, (3) C3H8, (4) C2H6, (5) CH4, (6) H2 [from Niedrach, J. Electrochem. Soc. Ill...

To achieve anodic film growth, two methods are widely used (i) application of a constant current (galvanostatic oxidation), (ii) application of an anodic potential (potentiostatic oxidation). 

During galvanostatic oxidation, the current density i remains constant. Differentiating equation (6.24) therefore gives ... 

An alternative approach to characterizing the inhibition process is chronopotentiometry. Figure 6(a) shows a series of chronopotentiograms obtained fi om tiie galvanostatic oxidation of a niobium wire. When the anodic current is applied, an oxidation of limited duration occurs in the 1.1 V to 1.2V range. The electrode potential then increases dramatically until an oxidation reaction able to support the applied... 

Figure 11.10 Galvanostatic oxidation and reduction curves of he birnessite electrodes synthesized by electrochemical cycling of Mn304 in (a) additive free, (b) 30 mmol dm" NaSCOs added, and (c) 30 mmol dm Na2HP04 added electrolytes at a rate of 1 A g . Electrolyte used was 1 mol dm Na2S04 aqueous solution.

Figure 4.25. Oscillatory phenomena dining galvanostatic oxidation of HCOOH on Pt at 0.15 mA cm in 0.9 M HCOOH - 0.5 M H2SO4 [136]. a) Pt electrode mass (indicated as fiequency change Af in quartz crystal microbalance measurements), b) Pt surface energy Af and c) electrode potential (With kind permission from Springer Science+Business Media Journal of Solid State Electrochemistry, Simultaneous oscillations of surface energy, superficial mass and electrode potential in the course of galvanostatic oxidation of formic acid, 9,2005, 347-53, Lang GG, Seo M, Heusler KE, figure 4.)...

Lang GG, Seo M, Heusler KE. Simultaneous oscillations of surface energy, superficial mass and electrode potential in the course of galvanostatic oxidation of formic acid. J Solid State Electrochem 2005 9 347-53. 

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