Introduction to Cyclic Voltammetry 

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Hahaha thank you. It was fun chatting with you too! I listened to some of "The Citrus Tree" It was very nice a chill...just as you described it :)

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Glad you liked it! If you have any follow up questions let us know. We've been trying to do livestreaming on Friday's to answer any and all electrochemistry questions.

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Thank you so much! We appreciate it. There is never a shortage of electrochemistry videos to be done, so stay tuned for more :)

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Thank you for watching it again. Yeah, I wanted to make sure I used better language to describe the double layer, and reframe from using the word "collide" when talking about electron transfer with the electrode surface. RU-vid doesn't allow me to replace existing videos, so it's just a complete re-upload.

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Glad to hear it. Best of luck on your job interview!

I'm glad you enjoyed the video and it was helpful to your learning!

Thank you! Yes, I was thinking the Nernst equation and eventually the Randles-Sevcik equation would be good topics for future videos. Stay tuned!

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Thanks so much for your comment, we appreciate it! Happy to keep making content for the electrochemistry community!

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CV is a complicated subject and the struggle is real. We're glad that this video helped with your understanding.

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Спасибо за добрые слова!

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Thank you Dylan! I'm glad you enjoyed all the videos we've made. I've got more ideas for videos, but if you have suggestions too. Or just general questions we are happy to help :)

@@Pineresearch For reduction to start occuring, it is not necessary that the potential applied has a negative sign right? It can still be positive but low enough (lower than the ferricyanide open circuit voltage perhaps?) to trigger the reduction process. Please help

@@glytslife That is correct, it is not necessary for the sign of the potential to be negative for a reduction reaction to start occurring. Similarly, the potential doesn't have to be positive for an oxidation to start occurring. I think of it as the fermi level or the standard potential of ferro/ferricyanide, when it comes to getting a reduction to occur. When a reduction occurs the standard potential of species in solution is lower than the potential of the electrode (governed by the potentiostat). That way, electrons will flow from the electrode to the species. This potential of the electrode can be positive with respect to the reference electrode. I hope this was helpful, let me know if you need some additional clarification. Trust me it's complicated :D

@@Pineresearch Hi there! Thank you so much for the video! I have a follow up question to your last comment, where you mentioned that, "When a reduction occurs the standard potential of species in solution is lower than the potential of the electrode (governed by the potentiostat). That way, electrons will flow from the electrode to the species. ". I guess for the species in the solution to get reduced, the standard reduction potential of the solution should be greater than that of the electrode as higher reduction potential means higher tendency of getting reduced. Can you please clarify?

@@anindyanath8136 This is a good question. I'm going to answer it during Episode #30 of our Ask Us Anything about Electrochemistry Livestream. The livestream is at 1 pm EST on Fridays so if you can make it that's great, but if not you'll be able to see the question in the description of the video. This might make it easier to explain what is happening.

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Working on it!

@@Pineresearch thank you!!!

That's a great idea. I think going over the math and data analysis for CV would be helpful. Another video to make :D thank you for watching!

Nobody is stupid when it comes to electrochemistry. It's very complex and we try to break it down. We're hoping to make more videos in the future :)

I'm glad you enjoyed it! I'm hoping it won't be too long until the next video :)

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We are grateful you enjoyed our video content, and thank you for the comment!

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Thank you! Alright we are getting more people interested in the mathematics behind CV. I haven't heard from too many others, but thank you for letting me know.

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Glad this was very helpful. I hope your final went well!

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No joke. I was talking to my colleague about doing a webinar on step and pulse voltammetry techniques. It might be some time before we make one, but it's definitely on our radar as another video/webinar we plan on making. Thank you for the support!

Thank you! Yes, I'll look into a few videos to breakdown the mathematics of CV

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Glad it was helpful! Yes, we plot everything using the IUPAC system.

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Glad you liked it! Welcome to the channel :)

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Thank you! Yeah, we've got a list of videos we'd like to make. It takes quite some time :D

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I'm glad the video was helpful. I can definitely put DPV and SWV on the list of videos to make. But it might take a while, I've got a long list of videos to make :)

Will try. I would need to speak to my colleagues about using the technique for batteries.

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Thank you RanjitDe! Chronoamperometry is definitely a video I'm planning on making in the near future.

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I'm glad the video has been helpful in your understanding of electrochemistry and CV. To determine the concentration from the voltammogram, the most straight forward way is to use the Randles-Sevcik Equation. This relates the peak current to a bunch of parameters like the scan rate, diffusion coefficient, area of the electrode, and the concentration. Once you know the other parameters you can use CV as a sensor and use a linear fit/calibration curve to relate the peak current to the concentration. I hope this was helpful. As an FYI, we hold weekly livestreams where you can ask us anything about electrochemistry. They are typically at 1 pm on Fridays EST on RU-vid.

Glucose by itself isn't electroactive, so you wouldn't observe an oxidation or reduction currents associated with glucose. However, some of the original technology for electrochemical glucose sensors was using the enzyme glucose oxidase that converted glucose and oxygen to gluconic acid and hydrogen peroxide. The hydrogen peroxide was electroactive on platinum electrodes. Today I believe there are more advanced technologies for electrochemical glucose detection.

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Thanks, will do!

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We're glad you enjoyed the video. We don't have any videos on selecting electrode/electrolyte solutions. But for studying powders, most scientist drop cast a solution of the of powder in a suspension, and allow it to dry on the working electrode surface. The working electrode in this case would be something inert like glassy carbon. The electrical double layer can be very complicated and the electrolyte solution will play a role in the capacitance. Sorry I can't be more helpful.

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Thank you. That's a great idea. I've got a list of videos I plan on making. I think that will go on the list too. Stay tuned for more!

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Oh no, I'm sorry to hear that! But I am glad you enjoyed our video anyway!

Glad you enjoyed the video! I'll put that on the list of many videos I need to make :D

Thank you we've got some ideas for future videos related to CV and EIS.

Thank you! Which electrochemical reaction mechanisms are you referring to? This one was basically a single electron transfer reaction. But there are a lot of different electrochemical reactions our there.

Many many thanks!

Thank you! I've got a lot of video ideas for the future, I'll eventually get to stripping voltammetry. But it might be a while.

Hello Chris, I'm glad you enjoyed the video. I'm entirely sure I know if what you are saying is possible. Is ruthenium oxide the working electrode material? Are you trying to calculate pH via CV? I believe it is possible, but it will be dependent on ruthenium oxides interaction with protons in solution and whether the change in the pH will create a change in the voltammogram.

It will depend on the system. But we did a live stream Q&A that goes over the selection of the potential range. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-8OavQwLmOPs.html Around 5:03 we talk about a general approach to determining the potential range. I hope this is helpful.

Thank you! I'll put chronoamperometry on the list of videos to work on :)

Thank you for stopping by and I'm glad you enjoyed the video. With regard to adding both oxidized and reduced forms of a species into solution (Ferrocyanide and Ferricyanide) it depends on the application. But in general the concentration of both species in solution will adjust the electrode potential as governed by the Nernst equation, E = E0 - RT/nF*Ln(Ox/Red). If you want to adjust the E of your system, you can do so by changing the concentration of Ox and Red. I hope that made sense, please let me know if you need further clarification.

@@Pineresearch thanks for you response and clarification. I just need to know that when the ferrocyanide reached towards the electrode surface (during positive cycle), electrode would take electron from the ferrocyanide and this species will become ferricyanide (up to this point I am well satisfied). But when we introduce both species then what will second species do at this stage when ferrocyanide became ferricyanide. Now we have ferricyanide adsorbed on the electrode surface due to the migration and we have also extra ferricyanide that we introduced previously in the electrochemical system.

@@physicsofcharacterizationt7570 Great question. First, it's important to note that in the mixed redox system (ferrocyanide + ferricyanide) you have changed the electrode potential in your system compared to the system where you only have ferrocyanide. Remember that the electrode potential is governed by the Nernst equation. Your electrode potential is different from the original system. So, your question can't be answered directly because by virtue of adding the other redox molecule you've changed the system. If you performed the exact same experiment as previously described, you'd initially see a spike in current followed by the decay (like in a chronoamperometry experiment), then you'd get the "duck-shaped" CV response. The spike in current is because you've initially moved the potential to a point away from the open-circuit potential, and that is a point where ferricyanide is thermodynamically favored. As a result faradaic current passes converting ferrocyanide to ferricyanide. The current decays as the surface concentration of ferricyanide gets depleted. As you continue to sweep the potential more positively, the ferrocyanide will oxidize to ferricyanide, and upon the switching potential, we would reduce the ferricyanide to ferrocyanide, getting the "duck-shaped" voltammogram. Was that helpful? I know it's quite a bit.

@@Pineresearch thank you 😊

Glad you enjoyed the video. What do you mean by "optimize the process of taking CV data"? Are you referring to optimizing the conditions for good CV data? Are the referring to placement of the electrodes? We do have a bunch of videos on how to interpret EIS data depending on what the system is and how to do circuit fitting. What system are you interested in?

@@Pineresearch Thank you for your swift reply, Yes how do we optimize the condition for taking the CV data? Regarding the electrodes, I am using a graphite sheet as a substrate and then I coat the slurry on it. So How would you go about it? And Regarding the system, I am working on both polymer electrolytes and different electrodes for energy storage, So can you do a video on how to interpret the EIS Data for these systems? Thanks once again, I am now a fan of your channel.❤

@@MatbiangShadap We are glad you like the channel ❤. Every electrochemical system is a little different when it comes to optimization of electrodes, but for a graphite sheet with a slurry on it, my guess is that you will want to place the reference electrode close to the working electrode. You probably also have a fairly large surface area working electrode, so you will need an even larger area counter electrode, perhaps one or two graphite rod electrodes. Depending on the conductivity of the electrolyte you are using you will probably want to determine the uncompensated solution resistance and determine whether or not you need iR compensation. Those are some starting points, but I'd first test your electrodes and electrochemical cell with a well characterized analyte like ferrocyanide or ferrocene. Because you'll know exactly what the response of ferrocyanide or ferrocene should be, you can then start to make adjustments to your system to get better data. Regarding EIS interpretation, we don't have a specific video on that kind of system. However, if you take our "How to Perform EIS Circuit Fitting on a SrTiO3 Perovskite Film" video, ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-wixp3pKvKMc.html at 3:21 we start to go over how to model the system, and more specifically at 9:42 we take about how to think about making an equivalent circuit model. You might that that helpful when modeling your system.

@@Pineresearch Thank you for your suggestion and more over thank you for your swift reply. You have just made me a great fan of yours. I will definitely try out your suggestion. Thanks once again.

I addressed this in your previous comment. Check out ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-8OavQwLmOPs.html around 5:03 we talk about determining the potential range.

Thank you for watching, and glad you found it helpful!

Definitely something to work on. Although I don't have much experience with super capacitors

Thanks for your question. Typically, CV is not the most preferred technique to use on batteries. In a recent livestream I talked about this a little bit, see this link for some additional context: ru-vid.comZb36oDPMW8A?si=BkIYVqvenOJyYXMx&t=2062 If you want more live, detailed discussion of this subject or others related to batteries, I invite you join one of our weekly livestreams on Fridays at 1pm EST (US eastern time). You can ask questions and I will try to address them live for you.

@@Pineresearch Thanks for your reply.

Cyclic voltammetry is not the only way to study the diffusion layer. Other techniques such as rotating disk electrodes (RDE) and EIS can help you determine the diffusion coefficient. To deeply understand the diffusion layer reading electrochemical methods fundamentals and applications by Allen Bard and Larry Faulkner is the best way to get a deep understanding of the diffusion layer. Our videos try to present a relatively simplistic but easily comprehensible understanding of the diffusion layer.

Thank you, glad you enjoyed it!