Beautifully presented ! Can't ask for more. 👍 An additional information for viewers how doesn't know, the type of adsorption discussed in the end is called chemical adsorption.
@Andrew McKinley, awesome presentation, and thanks for the clear and well-explained electrochemistry concepts. Is it possible to get your PowerPoint presentation? I would really appreciate having your material for my students.
Am doing Fuel Cell research paper, as an Engineering Major , the part about Exchange current density and Charge transfer is most confusing. Most of research paper just focus on other operating conditions and how they affects performance but very few mention CTC I have watched this video every time I read something confusing and this video help me understand the chemistry side. Thank you.
Thank you for your wonderful presentation. I had classes on this subject with 2 lecturers. One was just scrambling through it without providing any actual information. I had to spend hours reading Baard and Faulkner to understand the subject somewhat. The other lecturer focused too much on mathematical derivation, which is good for basic understanding, but I don't remember much all the math after the classes ended. Your presentation focuses on implication and example of BV and Tafel equations is really helpful for me.
Over potential = E - Eeq, so at positive over potential, E>Eeq, but we know that this condition represents electrolysis, so that is energy consuming(electron gaining), then why positive over potential corresponds to oxidation?. Are we talking about the electrodes or the species here?
It might be useful to consider it point-by-point: - By definition, current flows from positive to negative (anode to cathode) - Oxidation of the species in solution *always* occurs at the anode - These are always *relative states*; a negative voltage simply flips which is the anode/cathode. - When we do electrochemistry, we don't think about 'anode/cathode', we think about our "working electrode". - At positive potentials on the working electrode, we get oxidation of species in solution _at the working electrode_ , while when we switch it to negative potential, we get reduction of species in solution _at the working electrode_ . - We typically disregard what happens at the other electrodes! (usually a standard reference electrode and a 'counterelectrode' whose only purpose is to complete the circuit) With respect of "electrolysis", regardless of whether we have a positive or negative overpotential, we are driving a current through the cell (i.e. doing electrical work) - so it is, by definition, an electrolytic cell in any of these states. The only other possibility would be to connect a conductor between the two electrodes and let thermodynamics take the wheel - a "galvanic cell". Does this help to resolve the understanding?
@@aw_mckinley Yeah,Thanks.. That's what i asked.. Your answer mean that we are taking about the species in the solution and not about the working electrode,am I right?....
How is the over potential calculated in practical applications like what instrument can be used to determine the induced potential that deviates from the equilibrium potential?..so that the over potential can be calculated.
All you need to know is the equilibrium potential. There are vast tables of data for pretty much any redox species you can imagine. Then you need to adjust it for the reference electrode you are using. Best if you use RHE to begin with. After that you need to account for changes in temperature, pH (if pH sensitive), using the Nernst equation. Best example is HER. It is taken as definition of 0V for electrochemical scale in standard conditions - 298K and activities = 1. However, this then means that it is 0V only for solutions of pH=0 (as -log(1) = 0). Say you have a solution of pH=2 your new equilibrium potential for HER would be 0+0.059*2=0.118V. All that is left is to measure your CV and plot the j vs overpotential, assuming it is at 0.118V.
Understandable English. Very thorough. Clean Presentation. Good Job.
At 5:54, n-0.1?
Yes; apologies, this should be the *magnitude* of the overpotential, not its absolute value; so when |η| > 0.1.
Thanks for flagging it!
Very good and benefit me understanding exchange density
thank you very much!
Thank you very much for your very explicit explanation
Beautifully presented ! Can't ask for more. 👍
An additional information for viewers how doesn't know, the type of adsorption discussed in the end is called chemical adsorption.
The Langmuir-Hinshelwood and Elley-Ridel Mechanisms, respectively.
@Andrew McKinley, awesome presentation, and thanks for the clear and well-explained electrochemistry concepts. Is it possible to get your PowerPoint presentation? I would really appreciate having your material for my students.
Well explained
This made it all make sense! Very thorough yet precise!
Great video!
awesome presentation
GREAT PRESENTATION 👍
This video is incredibly well made.
Thank you!!
you are doing a great job!!
keep it up
Am doing Fuel Cell research paper, as an Engineering Major , the part about Exchange current density and Charge transfer is most confusing. Most of research paper just focus on other operating conditions and how they affects performance but very few mention CTC
I have watched this video every time I read something confusing and this video help me understand the chemistry side. Thank you.
Thanks for this impressive explanation. You delved into some intricate details about all the parameters.
Thank you for your wonderful presentation. I had classes on this subject with 2 lecturers. One was just scrambling through it without providing any actual information. I had to spend hours reading Baard and Faulkner to understand the subject somewhat. The other lecturer focused too much on mathematical derivation, which is good for basic understanding, but I don't remember much all the math after the classes ended. Your presentation focuses on implication and example of BV and Tafel equations is really helpful for me.
Fantastic presentations so far Andrew McKinley! Thank you for helping me digest a difficult research
THankyou Sir.
Over potential = E - Eeq, so at positive over potential, E>Eeq, but we know that this condition represents electrolysis, so that is energy consuming(electron gaining), then why positive over potential corresponds to oxidation?. Are we talking about the electrodes or the species here?
It might be useful to consider it point-by-point:
- By definition, current flows from positive to negative (anode to cathode)
- Oxidation of the species in solution *always* occurs at the anode
- These are always *relative states*; a negative voltage simply flips which is the anode/cathode.
- When we do electrochemistry, we don't think about 'anode/cathode', we think about our "working electrode".
- At positive potentials on the working electrode, we get oxidation of species in solution _at the working electrode_ , while when we switch it to negative potential, we get reduction of species in solution _at the working electrode_ .
- We typically disregard what happens at the other electrodes! (usually a standard reference electrode and a 'counterelectrode' whose only purpose is to complete the circuit)
With respect of "electrolysis", regardless of whether we have a positive or negative overpotential, we are driving a current through the cell (i.e. doing electrical work) - so it is, by definition, an electrolytic cell in any of these states. The only other possibility would be to connect a conductor between the two electrodes and let thermodynamics take the wheel - a "galvanic cell".
Does this help to resolve the understanding?
@@aw_mckinley Yeah,Thanks.. That's what i asked.. Your answer mean that we are taking about the species in the solution and not about the working electrode,am I right?....
@@ramanujasrinivasans1898 Yes - in this context we're talking about the solvated species.
How is the over potential calculated in practical applications like what instrument can be used to determine the induced potential that deviates from the equilibrium potential?..so that the over potential can be calculated.
All you need to know is the equilibrium potential. There are vast tables of data for pretty much any redox species you can imagine. Then you need to adjust it for the reference electrode you are using. Best if you use RHE to begin with. After that you need to account for changes in temperature, pH (if pH sensitive), using the Nernst equation.
Best example is HER. It is taken as definition of 0V for electrochemical scale in standard conditions - 298K and activities = 1. However, this then means that it is 0V only for solutions of pH=0 (as -log(1) = 0). Say you have a solution of pH=2 your new equilibrium potential for HER would be 0+0.059*2=0.118V.
All that is left is to measure your CV and plot the j vs overpotential, assuming it is at 0.118V.