I am trying to deposit Prussian blue on an Au electrode using cyclic voltammetry for Glucose sensor. I use the commercial Ag/AgCl reference electrode. The counter electrode is connected to ref and working is an Au electrode. However, I do not get a good deposition. The adhesion of PB on the Au electrode is not good and when I take the electrode out of the solution, I can see the PB is washed away from the electrode.
I am using ferric ferricyanide solution:
2.5mM FeCl3 + 2.5mM K3Fe(CN)6 + 0.1M KCl + 0.1MHCl
in 0 V to 0.5 V with 50mV/s scan rate of CV.
What should I do to improve the adhesion of PB to my Au electrode? Do I need any treatment before or after the deposition?
See
Article Spontaneous Deposition of Prussian Blue on Multi-Walled Carb...
It is not a good idea to connect CE to REF, this way you have a two electrodes cell and you lose control on the actual potential of the Au electrode. Use of a 3 electrodes cell is compulsory for a true cyclic voltammetry.
Hi,
It might be necessary to increase your potential window to higher positive values (+0.9 V) to come to good deposition on gold electrodes. See this article for more details:
https://doi.org/10.1016/j.jelechem.2005.07.008
I think it makes sense it is better deposited at this higher potential value since your gold starts oxidizing as well at this potential. This way, the PB can partially incorporated in the gold structure (at the surface) during this process, and can it more easily be immobilized.
The researchers of this article also optimized other experimental conditions, so you could compare these to yours. It should be possible without any special electrode modifications.
Hope this helps.
Kind regards,
Mats
Although I have no direct experience with this particular electrodeposition, I agree that using the three-electrode cell should be used for proper potential control. Also, why use cyclic voltammetry? Why not simple electrodeposition at a fixed potential? I remember many years ago using what is called a Hall cell to optimize electroplating parameters. This type of cell allows the determination of the optimum voltage and current density for the electrodeposition.
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