In doing an experiment which involved depositing gold nanoparticles by cyclic voltammetry, I was told the amount of gold that has been deposited can be estimated by comparing the size of the reduction peak in the cyclic voltammogram. The procedure used is as follows:

  • Submerge electrode in HAuCl4 solution and set the scan to a negative potential. This reduces gold and deposits it on the surface of the electrode.

  • Submerge the electrode with gold deposited on it in sulfuric acid and perform a cyclic voltammetry scan. A reduction peak appears, as well as an oxidation peak.

  • The reduction peak can be used to estimate the surface area of gold deposited by integration, and comparing the height of the reduction peak can also give a rough idea of how much gold has been deposited on the electrode.

It appears a similar process cannot be carried out on the oxidation peak. I can't think of a reason why that is the case, since, from what I understand, the reduction process is the reversal of the oxidation process, in which hydroxide or oxides formed in the lattice are driven back to the surface. So why are oxidation peaks not examined when estimating the amount of gold deposited or the surface area of gold deposited?

This is the voltammogram I am asking about (own data). enter image description here


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