Ideas in this lecture: -Hemholtz double layer at ~1nm at the electrode-electrolyte interface (double layer capacitor 10-50uF /cm^2) -Gouy Chapman model: charge distribution takes place ~10nm from the interface (applicable at low conc like 1 mM) -Stern model combination of both models -Faradaic transfer in electrochemical reaction + double layer capacitance > Zf || Cdl -Minimum 2 electrodes required in a electrochemical setup, Rsol > resistance of solution -We cannot directly measure the potential of an electrode as any probe develops double layer and thus potential drop -Reference electrodes in a 3 electrode system are used as they have a constant potential drop from solution and very little impedance(negligible) -luggin capilary used to place ref electrode close to working electrode to reduce the effect of Rsol -Counter/aux electrode is used to complete the circuit, have large surface area(low current density) because at large current, ref electrode doesnt have constant potential drop -potentiostat has to have fast response, closed loop, measure small currents -2 electrode systems enough for measuring electrical impedance -Applied voltage: b/w working and ref; compliance voltage: b/w working and counter -Very small current for ~1.8v, current exponentially increases due to water splitting. :. limit experiments not studying water splitting to 1.8v - Increase this range by using Zn or Pb electrodes or non aq solvents -Supporting electrolyte: increases conductivity w/o interfering w/ reaction, reduces effect of Rsol
thank you professor for such an awesome lecture. however, i did not understand the concept from 24:20 to end of this lecture can you provide some literature on this??
Excellent explanation. What would be the potential of the working electrode and the reference electrode? Can I say they are connected in parallel and have the same voltage?
Not really (unless we mistakenly connect the working and reference electrodes together). We visualize potential as a quantity that is measured with respect to some reference. point. The reference point could be the electrolyte, but we are unable to measure it. So we end up using a reference electrode.
You can refer to the youtube play list ruclips.net/p/PLyqSpQzTE6M9ftJKyUWBilfrgBjh_6eh1 Unfortunately it is not in order :-(, and the other site nptel.ac.in/courses/104106105/ isn't working
Technically, you can. But in my experience, I think it isn't advised because the working electrode is usually the electrode you are interested to study while Reference electrodes are usually the ones that have been established for a while and they serve to make sure the change in applied potential is only affecting the working electrode. So, you can try out different working electrodes while keeping the reference electrode the same. (I hope this helps)
We can't measure the electrochemical property of electrolyte without the help of (a minimum of) two electrodes. Having said that, the non-reactive components of the electrolytes are expected to behave as a simple resistor.
Ideas in this lecture:
-Hemholtz double layer at ~1nm at the electrode-electrolyte interface (double layer capacitor 10-50uF /cm^2)
-Gouy Chapman model: charge distribution takes place ~10nm from the interface (applicable at low conc like 1 mM)
-Stern model combination of both models
-Faradaic transfer in electrochemical reaction + double layer capacitance > Zf || Cdl
-Minimum 2 electrodes required in a electrochemical setup, Rsol > resistance of solution
-We cannot directly measure the potential of an electrode as any probe develops double layer and thus potential drop
-Reference electrodes in a 3 electrode system are used as they have a constant potential drop from solution and very little impedance(negligible)
-luggin capilary used to place ref electrode close to working electrode to reduce the effect of Rsol
-Counter/aux electrode is used to complete the circuit, have large surface area(low current density) because at large current, ref electrode doesnt have constant potential drop
-potentiostat has to have fast response, closed loop, measure small currents
-2 electrode systems enough for measuring electrical impedance
-Applied voltage: b/w working and ref; compliance voltage: b/w working and counter
-Very small current for ~1.8v, current exponentially increases due to water splitting. :. limit experiments not studying water splitting to 1.8v
- Increase this range by using Zn or Pb electrodes or non aq solvents
-Supporting electrolyte: increases conductivity w/o interfering w/ reaction, reduces effect of Rsol
25 mins in this lecture equal several months reading textbooks, with an easy and thorough explanation. Thank you very much, teacher.
I watch this video to understand double layers and find out more about electrode knowledge. It's great !
And hello to my countryman :))
this professor speaks the best English among all educational Indian youtubers.
@Moonmoon Patii'd like to get nutrition from food, but i also want them to be cooked delicately.
The best explanation about electrode system I have ever seen. Thank you so much.
Very good class..best explanation
Excellent presentation. Thanks🌷
This is what I really need it. Thank you!
Interesting lecture,...
awesome ,nice presentation sir
thank you professor for such an awesome lecture. however, i did not understand the concept from 24:20 to end of this lecture can you provide some literature on this??
You have to see that the black graphic is a relation between the potencial at Y axis and the X axis is the distance from the electrode
Thank you a lot for putting this out in the internet!
Is it possible to get the powerpoint presentation too?
Excellent explanation. What would be the potential of the working electrode and the reference electrode? Can I say they are connected in parallel and have the same voltage?
Not really (unless we mistakenly connect the working and reference electrodes together). We visualize potential as a quantity that is measured with respect to some reference. point. The reference point could be the electrolyte, but we are unable to measure it. So we end up using a reference electrode.
Where is the next class of this course ? Very nice lecture.
You can refer to the youtube play list ruclips.net/p/PLyqSpQzTE6M9ftJKyUWBilfrgBjh_6eh1
Unfortunately it is not in order :-(, and the other site nptel.ac.in/courses/104106105/ isn't working
Thank you that really what I need you
Thank You
think you sir
Do you recommend any book?
thanks a lot sir.
can we use the same material for working electrode and reference electrode?
Technically, you can. But in my experience, I think it isn't advised because the working electrode is usually the electrode you are interested to study while Reference electrodes are usually the ones that have been established for a while and they serve to make sure the change in applied potential is only affecting the working electrode. So, you can try out different working electrodes while keeping the reference electrode the same. (I hope this helps)
@@adityaprajapati2688 thank you
super sir
How to become a CP Engineer?
Can we find the nyquist behaviour of the electrolyte itself.How?
We can't measure the electrochemical property of electrolyte without the help of (a minimum of) two electrodes. Having said that, the non-reactive components of the electrolytes are expected to behave as a simple resistor.