𝔖 Bobbio Scriptorium
✦   LIBER   ✦

Anodic behaviour and passivation of a lead electrode in sodium carbonate solutions

✍ Scribed by E. E. Abd El Aal; S. Abd El Wanees; A. Abd El Aal


Publisher
Springer
Year
1993
Tongue
English
Weight
551 KB
Volume
28
Category
Article
ISSN
0022-2461

No coin nor oath required. For personal study only.

✦ Synopsis


Cyclic voltammograms of a lead electrode were obtained in Na2CO 3 solution as a function of the starting potential, electrolyte concentration and voltage scanning rate. The shape of the voltammograms was found to depend on the starting potential as well as the sweep number. This is probably due to changes in the activation state of the electrode surface. The first anodic portion of the voltammograms is characterized by a shoulder and two peaks corresponding to the formation of PbC03, PbO and PbO2, respectively. The cathodic portion shows the occurrence of two peaks corresponding to the reduction of Pb02 to Pb0 and PbO to Pb, successively, followed by the formation of PbH 2. An increase in concentration of CO~ions leads to a negative shift in the values of the peak potentials, Ep, accompanying the formation of Pb0 and Pb02. In addition, the current density for both the anodic oxidation peaks showed marked dependence on the concentration of the electrolyte. An increase in the scanning rate was observed to lead an increase in the size of the voltammograms. The current density of both the anodic peaks and the anodic passivation region were proportional to v 1/2 Such behaviour is expected in a diffusion-controlled processes. In addition, the anodic peaks are shifted towards more positive values of potential, whereas the cathodic peaks are shifted in the negative direction, indicating irreversible formation of the passive film on the electrode surface.


πŸ“œ SIMILAR VOLUMES


The anodic behaviour and Passivity of Ti
✍ Prof. Dr. I. A. Ammar; S. Darwish; M. W. Khalil; A. Galal πŸ“‚ Article πŸ“… 1983 πŸ› John Wiley and Sons 🌐 English βš– 669 KB

Passivation of spec-pure Sn was studied in aerated, unstirred solutions of acid sulphate (H2S04/Na2S04) and neutral suphate (Na2S04) using the potentiodynamic technique from an initial cathodic potential (-ve to open circuit potential) in the anodic direction and backwards to the initial potential.

Anodic behaviour of a mercury electrode
✍ C. Muller; J. Claret; J.M. Feliu; J. Virgili πŸ“‚ Article πŸ“… 1982 πŸ› Elsevier Science 🌐 English βš– 248 KB

Anodic dissolution of the hmde from %hydroxyquinoline (Ox) aqueous solutions at pH = 5.2 is attributed to the formation of insoluble organomercuric derivatives. The experimental results show that the process happens in two steps. The first one takes place with adsorption of electroactive species, wh

Potentiodynamic reactivation of a passiv
✍ Yoshifumi Yamamoto; Masao Matsuoka; Mamoru Kimoto; Masahir Uemura; Chiaki Iwakur πŸ“‚ Article πŸ“… 1996 πŸ› Elsevier Science 🌐 English βš– 419 KB

When a fully charged lead negative electrode stood for one month in 1.0 M H,SO, solution at a temperature of 298.15K, it was passivated through so-called "sulfation" as indicated by a decrease in the redox peak currents on cyclic voltammograms. As a method of reactivating the passivated lead negati