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Oghbaei, Shabnam | 2010

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 40966 (03)
  4. University: Sharif University of Technology
  5. Department: Chemistry
  6. Advisor(s): Ghabl, Feridon
  7. Abstract:
  8. The purpose of this study is to investigate the effect of halids on electrooxidation of silver in alkalie medium. For this case, electrochemical teqniques such as Chronoamperometery (CA) and Cyclic Voltammetry (CV) were applied. Characterization of the electrodeposition process is based on quantitative analysis of the potentiostatic current versus time curves. Rate constants of nucleation and growth obtained from the fit of the recorded transients to the generalized equations derived based on Abyaneh and Flischmann model. The conditions that justify the use of the limiting forms of the transient equations for the so-called “ instantaneous” and “ progressive” nucleation processes were evaluated. Effect of potential and concentration on the kinetics and mechanism of this process were investigated. It was found that the deposition process for AgO on the silver electrode could be well described by a model that involves five contributions: (1) a double layer charging process( IDL) (2) an instantaneous Two-dimensional nucleation and growth(I2DI) , Two different kinds of Three-dimensional nucleation mechanisms, (3) an instantaneous( I3DI) and (4) a progressive (I3DP) Finally, (5) two processes, “ death” of growth center and the “ rebirth” of new centers( IS). By adding little amount of halids in alkaline solution, the deposition process for Ago changed to other contributions. By adding Iodide or sulfide to the alkaline solution, nucleation and growth process not be seen on deposition process for AgO and has monolayer deposition
  9. Keywords:
  10. Cyclic Voltammetry ; Electrodeposition ; Electrocrystallization ; Chronoamperometry ; Silver Electrode

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