In the initial E(t) graph could someone explain why the time when the maximum voltage is reached is ,,lambda" and when the potential is reversed and reaches the initial value on the time axis is ,,lambda/2"? I think if the scan rate of the applied voltage is constant the two periods to be equal and, therefore, the maximum voltage value is reached at ,,lambda/2" point. On the other hand, thanks a lot for your informations and I am waiting your future videos with explanations about cyclic voltammetry!
Is the electrode Ferrocene? What would happen if you have gold as the anode, an oxygen ion conductor as the electrolyte and at the cathode Ruthenium? I was wondering if we would see both Au and Ru at the CV graph. Thanks a lot.
Hello everyone! I have a question about CV. It is known that current in CV depends on different controlling mechanisms: at low potentials before peak current there is surface control and after - diffusion control. Also it is known that changing of sweep speed give us information about surface or diffusion limitation of our reaction. But i cannot understand how type of limitation of our reaction connected with CV limitations at different potentials...
very clear explanation! Can this technique be used to establish the optimum current density for electroplating? We are currently looking at plating Co onto SS316 (for recovery from LithiumCoOxide cathodes from lithium batteries) but test runs using an MMO anode suggests that there is competition between plating and hydrogen evolution.
10:41 When I do CV on my samples, the peaks are consistently around 0.2-0.4V apart (depending on solution concentration) and is a reversible reaction. How would that be translated to the 0.059/n volts part of the Nernst equation? What does n < 1 even mean or can it be possible? How many electrons are being transferred during oxidation/reduction at each point?
The 59/n mV is only for ideal situations. In many cases, your experimental set-up might have uncompensated resistance or other reasons that electron transfer to and from your electrode to your molecule might be slow, leading to wider peak separation. If you're running CV in organic solvents, some solvents in particular like THF might also show higher peak separations compared to solvents like acetonitrile.
Hello Mam, this is a very informative lecture. I really liked it. I have a question - you have mentioned that "Never Stir" at 4 min 53 secs, what does it mean? Why not stir?
Can anyone explain at 10:22, why detla E = Eanodic - E cathodic instead of Ecathodic - Eanodic as it is is in Electrochemical cell potentials? Is it as simple has because we are pumping energy in ? As in electrolytic vs galvanic?
Because in this case the anodic peak is at a higher potential than the cathodic peak. I’m pretty sure it’s just for the sake of keeping the value a positive number. And we aren’t really pumping in anything, it’s sort of like cooking. Some things just won’t cook unless they reach a certain temperature, same way that some things won’t oxidize/reduce unless they reach a certain voltage, which can be positive or negative
What happens if you do not sweep the potential up to the value in t=lambda? Let's say you increase for example to a value lower than E_p,a, does this mean that no electrochemical reaction happened and you would go back following the same path upon decreasing of the voltage? If anyone knows, thanks!
I'm not sure about this but I think you would build up a capacitive current and when going back you would take another path that would nearly the same as the double layer is decaying. But maybe I'm wrong. Good luck finding the right answer, or if you have the opportunity just measure a material yourself and try it out.