Questions related to Electrocatalysis
I want to measured the ECSA of a trimetalic alloys to be used for electrocatalysis. Additionally what could be better way to evalute ECSA of oxide materials for electrocatalysis? Further how could I measure ECSA of a metalic or multimetalic alloy supported on a oxide matrix?
Please help me.
Pt has been remarkable Hydrogen Evolution Reaction electrocatalyst in Acid which perform good even in large scale electrolysers.
While there are plenty of engineered HER catalyst reports most of them fail at reasonably high currents and long term testing. I wonder if there is any catalyst with higher intrinsic activity than Pt?
Dear colleagues. I'm studying ORR on carbon materials, including graphene oxide. I'm new in this research direction and have questions: what are the compositions of the most suitable electrolytes for ORR on carbon materials? In many research papers, 0.1M KOH is presented as the most suitable one. But, acidic and neutral solutions could also be good? I need the clear understanding of the rules behind choosing the electrolyte for ORR. Any good papers, clear answers, please, share with me.
I am planning on transitioning towards Power-to-X with a focus on water splitting and CO2 to fuel applications. However, there is still a lot that I need to learn before I can start working on the subject. Can you please recommend some good resources to start understanding these techniques from the very basics?
I am doing electrocatalysis, OER. I did Chronoamperometry, and tried with and without RDE setup. In both cases, In the working electrode Bubble formation, was there. How to avoid this?
I am getting a chronoamperometry graph after 1h (electrocatalysis starts) current value increases, then decreases, again steady state, and repeated after 30 min once.
I am using ametek potentiostat.
May I know about this?
How can we combine photocatalysis with other technologies, such as electrocatalysis, to achieve more efficient and versatile energy conversion and storage?
We are studying on PEMFC electrocatalysts via magnetron sputter systems on carbon paper substrates. By this way we can perform CV and RDE experiments without using ionomer dispersion.
Right now i have to decide on the preparation method of MEA.
-I am worried about if micropippet drop or spray bottle is the best ionomer coated method? (I don't have any other option, maybe paint brush)
-What should be starting value for the ionomer/catalyst mass ratio?
-Can temperature of hot press be a reason of agglomeration of particles (above T=100C)?
-Thickness of the catalytic thin film is blow 50 nm.
I want to do BET surface area analysis of Ni foam sample. what will be the degassing time and temperature and number of points to be consider for analysis. and any other specific details to follow?
Hi everyone I want to test the electrocatalytic activity (Overall potential at 10 mA/cm2 and long-term stability) of my Bifunctional electrodes in a two-electrode system which means that I have to take both anode and cathode of the same materials. I am a bit confused about the setup and how will I assemble my experimental setup (Potentiostat) to measure these parameters? Expert answers will be highly appreciated.
Please anyone give us what is the significant difference between photocatalysis, electrocatalysis, and photoelectrocatalysis
Hi, I'm graduate student working on electrocatalyst.
Most of the research article about electrocatalysis HER only measure the electrochemical performance ,such as LSV, Tafel slope, overpotentail. The production rate of hydrogen is seldom measured by research group.
Is the alkaline electrolyte won't have other reaction except HER?
I appreciate your help and sorry for my poor english.
I have calibrated my reference electrode and it is showing the correct onset on par with reported literature. However in doubting my results and want to double check the authenticity of my reference. Please suggest any such measures
I am doing oxygen reduction in 0.1M KOH at a glassy carbon electrode coated with an electrocatalyst (with conductive carbon support, ethanol, nafion). When I do impedance at OCP I get the red Nyquist plot. When I apply an ORR potential I get the blue Nyquist plot.
I can't work out why I have the initial semi-circle (present both at OCP and during ORR) as it isn't in any literature examples. I can't find a circuit model that models these data well.
Any help would be appreciated.
My PhD research includes degradation and stability study of fuel cell Pt/C catalysts for ORR. This is a new area of research, both for me (I'm coming from TEM background) and my lab, which is why I'm learning most experimental procedures and parameters from papers rather than more experienced colleagues.
Unfortunately, it seems to me that there's no agreement in electrochemical community regarding said procedures/parameters and here I would like to specify what causes my confusion:
- regarding CV and LSV procedures, from what I've already read and from my experimental data, it seems that scan speed influences ECSA data (extracted from H2 adsorption region on cyclic voltammograms) and activity data (extracted from linear scan voltammograms). Yet, I see different papers publishing data obtained with different parameters, which for me makes the results virtually impossible to compare. Additionally, some procedures include the so called electrochemical cleaning and stabilisation of the working electrode by performing 40-100 CV scans with higher speeds (100-200 mV/s), yet some papers seem to omit it. With LSV some procedures call for background subtraction of LSV data obtained from the measurement performed in N2 saturated electrolyte but again, not all papers include that step (yet both approached seem to be acceptable for publication).
Regarding accelerated degradation testing, the procedures seem to be a lot more all over the place:
-different scan speeds
100-500 mV/s, and from my experimental data I already see that scan speed influences degradation rate,
-different approaches to experiment
continuous scan vs 'sample and hold' (square wave) scan,
-different potential ranges
lower limit being 0,4 - 0,6 V, higher 0,9 - 1,2 V for operating condition testing, start-stop testing seems to be consistant 1 - 1,5 V,
-different "atmosphere" of electrolyte
O2 saturated, deoxygenated and "as prepared" electrolyte, all of those seem to be leading to publishable results.
So to sum up my stream of consciousness:
I'm not looking for specific experimental parameters (although getting some suggestion on those would be more than great) but rather some insight on the general consensus in electrochemical community regarding said parameters and why discrepancies in them seem to be widely accepted. Also, if someone feels like they have more spare time than they can utilise, I would be more than willing to participate in an internship in a unit focused on degradation/stability study of catalysts.
Thank you and have a great day,
For quite some time now we're trying to employ IL-TEM technique in our lab. In this method the catalyst is deposited on TEM grid, some regions on the sample are chosen for detailed investigation, then the grid is placed in electrochemical cell and the accelerated degradation test is performed (several thousand CV scans). After degradation test the sample is placed back in the microscope, and regions chosen before are examined again.
Literature on the topic is rather ambiguous regarding potential ranges, number of scans, methods of holding the TEM grid in the cell.
Recently we've managed to obtain some promising results, but we're still dealing with a massive problem of gold (originating from grid) dissolution and re-deposition on the sample (most visible in image A3_after_2). This problem seems to be dependant on the upper limiting voltage I'm choosing - the higher the voltage the more of a problem gold becomes. Images I'm attaching come from the measurement performed in 0,4 - 1,2 V (RHE) range, with 200 mV/s scan speed in air saturated electrolyte. The sample was removed from cell after 6000 CV scans, examined, then placed back in the cell for another 12000 scans. It was possible to find some places without gold, but the success of a procedure is hugely luck-dependant. During that measurement the sample was held in self-locking tweezers, which were not in contact with electrolyte. Regarding the sample mounting method I tried few things:
1. Sandwiching the sample between 2 glassy carbon plates.
The plates were immersed in the electrolyte. For some reason this method, with same parameters as the tweezer method, resulted in higher gold contamination.
2. Using 3d printed caps to attach the grid to the electrode
No changes in the catalyst were observed. There was no gold either, which suggest problems with the contact
3. Attaching grid to the electrode or the glassy carbon plate with teflon tape.
Same case as 2., no changes.
4. Attaching grid to the gold plate using teflon tape, resulted in massive gold contamination.
I'm more experienced microscopist than electrochemist, so it's more than possible that I made some electrochemistry-related errors (obvious for someone with experience) during my measurements and I would be more than grateful if someone could point them out.
What I'm most interested in is some advice regarding how can I limit gold contamination during the experiment, as well as some general IL-TEM tips.
Literature shows methanol oxidation in direct methanol fuel cell (DMFC) takes place by noble metals like Pt, Ru etc. Could we use other transition metals or non-metal nanocomposites for the oxidation of methanol. what are the things to be considered for selecting electrode material for DMFC or DEFC
Which porous materials (Micro/Meso/Macroporous) are very suitable for the electrocatalysis application (ORR, OER and HER)
Hi I am trying to synthesize quantum dots for the fabrication of electrodes for HER. I have metal oxide power so conventionally people use plates as target for production of Quantum Dots. So is it possible to use powder as target precurosor for synthesis of Quantum dots?
I want to compare the HER and OER results of metal strips that I have prepared now in elecrtochemical workstation I am using those strips of 0.5 cm*0.5 cm as working electrode. Now in order to compare it with standard commercial Pt/C should I deposit Pt/C slurry on glassy carbon electrode and then do analysis to compare the results or there is some alternative method to prepare commercial Pt/C like a those of square metal strips I am using?
If I have to use GC then should the area of GC and metal strips be equal or not ?
I am trying to build an aqueous and solid-state zinc-air battery that will utilize a 3-6M KOH solution as an electrolyte. I would like to order a current collector for the air-cathode side and I have been torn between Ti, Ni, or stainless steel mesh.
Both the Ti and Ni mesh are relatively expensive (£100+ for 15cm by 15cm meshes), with Ni possibly contributing to OER activity during charging however likely corrode to form NiO and Ti being generally known for its chemical stability. Furthermore what kind of wire thickness of the mesh would be most suitable? Am I correct in thinking that smaller wire mesh will provide greater contact area and oxygen permittivity, so I should aim for the smallest available?
Would someone kindly provide me with a little bit of advice on the matter? Many thanks
I have several curves of applied potential versus electric current with hundreds of points in each of them. I am trying to analyze their first and second derivatives, but they are too noisy to make sense.
I have tried using the Smooth tool in Origin, however they have several different smooth algorithms. How can I choose which Algorithm is best suited for my data?
I've recently reached the point in my work when I will need to conduct some electrochemical measurements, but unfortunately I have to start everything from scratch, because in our lab no one was ever doing measurements of electrocatalysts. Basically, I'm looking for any kind of instructions on how to perform ORR measurements. Right now I'm playing with commercial Pt/C catalyst, I'm using glassy carbon working electrode, platinum counter electrode, Ag/AgCl pseudo-reference electrode and 0,1 M H2SO4 electrolyte. I'm trying out different inks with different Nafion concentrations, but so far all my CV spectra have no resemblance of the ones presented in literature.
Thank you in advance for any suggestions.
In case of electrocatalysis, if we use gold nanoparticles stabilized by different organic moieties like flavonols, curcumin, curcuminoids, PVA, citrates, etc. Will it decrease the efficiency of the electrocatalysts towards oxidation of electroactive molecules such as dopamine, serotonin, ethanol and methanol? Will it increase the poisoning on the electrode surface?
How do magnetic field increase the electrocatalytic activity? How do magnetic field affect the reaction process? Some of the papers mention that magnetic field generate magnetohydrodynamic effect, some of them mention about spin alignment of oxygen as paramagnetic, and others mention that magnetic field helps to lower the binding energy between active material and oxygen.
Does anyone have another hypothesis or opinion?
I have just started to gain basic information about gas sensing materials. So here, I want to know what materials are in touch nowadays for efficient gas sensing, and what are the corresponding advantage and disadvantages?
The ORR polarization plot in the paper (the one with many colors) is very sharp but that of my catalyst is really smooth. I guessed that it is because all the activity sites in my catalyst have high reaction potential (bad thing for a catalyst). Is it right?
And how to improve my catalyst?
We are performing electrocatalytic CO2 reduction experiments and are unable to measure the low quantities of CO that we are producing. This may be due to a large excess of CO2 (20 mL/min) that we are flowing through the cell.
We are using Soprane GC machine with Molecular sieve 5A, 10 m long column.
I'm going to synthesize nanoparticles of lead dioxide and then I want to disperse them on the support of TiO2 nanotubes to make a catalyst. So would you please suggest me a procedure that I can almost disperse pbo2 on my support homogeneously?
Whenever I pyrolyzed NaH2PO2, I am facing difficulties in cleaning the left over white residue (may be phosphates) in the tube.
So, I am looking for any effective cleaning protocols to get rid of this issue.
My trouble here is understanding how to ensure results at different pH are comparable. I am asking this because different buffers have different ions and hence different electrochemical properties right? Can I just use a buffer of X pH and Y mM concentration or do I also have to add some third salt to it to adjust the conductivity somehow?
I'm a first year PhD student (1 month in) looking into the activity of an oxidation electrocatalyst, similar to TEMPO. I would like to see what kind of conversion rate I can achieve over a couple of hours. My cell is always made up to 3mL and I use around a 2mM concentration of my catalyst. What kind of ballpark concentration should I be using for my substrate? My CV analyses have been using around 200mM substrate when looking into catalyst diffusion coefficients, as to not limit the current to the diffusion of the substrate, but I have no idea if this is very high, very low, or just right for an amperometry experiment.
Thank you in advance!
Supporting electrolyte concentration: 0.15-0.25M
Solvent used: DCM
In many areas of electrochemistry (electrocatalytic water splitting, CO2 reduction, N2 reduction, etc.), we must relate electrochemical data (current, potential) to on-line chemical quantification data (from e.g. gas chromatography, mass spectroscopy) to properly characterize processes and determine Faradaic efficiencies of electrochemical transformations under different conditions. The challenge is that this requires multiple different sets of hardware & software, and produces data output in different formats and with different time scales. Such systems typically aren't designed to work together automatically, so the researcher must typically spend significant time on post-run data workup to represent the results in a meaningful way.
To those working in this area: What are some strategies for automating the analysis of these combinations of data? Of course, with clever programming (and considerable effort), one could make their own unified software managing everything (e.g. in LabVIEW), but surely there are examples of simpler approaches which people use. I am curious to hear how you do it -- and hopefully this conversation can be mutually helpful for everyone.
Are the explanations below enough to explain their 20%Pt/C superior performance?
Explanation1: The good stability of N-doped carbons has to be mostly ascribed to the covalent bonding of the catalytically active heteroatom to the carbon structure, unlike the physical bonding of Pt to carbon support. (Antolini, 2016, 10.1016/j.rser.2015.12.330)
Explanation2: The introduction of N atoms into carbon increases the electronic density of states near the Fermi level, thus facilitating the electronic transfer from the electronic bands of C to O2 σ* antibonding orbitals.(Xiaoming Ge, 2015, 10.1021/acscatal.5b00524)
Below are listed some of the properties of the metal-free electrocatalysts:
Elemental analysis: 0.5% wt. nitrogen, 4.5% wt. sulfur, 2% hydrogen EDS: 70% carbon BET: 2000 m2 g-1 Raman: Id/Ig = 1.23 (amorphous, defects) XPS: N-pyridinic and N-graphitic presence
I am working on synthesis of graphene based ORR catalyst from biomass and examined it in 0.1M KOH and got the results. The CV was done with glassy Carbon electrode(WE), RHE(RE) and platinum electrode(CE). I have synthesized two different catalyst labeled as Catalyst 1 and Catalyst 2 from two different biomass. The catalyst loading on GC electrode was 40mg per sq. cm. For each catalyst sample, First CV was performed with Nitrogen purging condition followed by oxygen purging condition at scan rate of 50 mV/s.
As you can check in picture, that I am getting peaks at different potential for these two catalysts in oxygen purging condition.
a). Why for these two catalysts, ORR reaction starts at two different potential even if both are nitrogen doped graphene?
b). Why the CV of Catalyst 1 is different than catalyst 2?
c). what kind of peaks are observed in catalyst 1 at near about 0 potential(Both in N as well as in Oxygen purging condition)?
d). Why these catalysts do not show any activity in perchloric acid?
e). Is there any use of ORR catalysts showing activity only in alkaline medium?
f). What are other relevant information and conclusion we can draw from this CV result?
It will be very helpful if you help me to get the answer of any of those questions mentioned above.
The file is attached with the question.
I made several ORR catalyst for PEMFC but after putting the catalyst in vial/glass bottle/polybags, I observe decrease in onset/peak potentials with the passage of time. e.g. if I test my catalyst today then its performance is good but after some days/month in a vial, I make fresh catalyst ink and its performance is very bad. Is it normal that every NPMC degrades like this (attached) with the passage of time? what's the cause of this sort of degradation and how should we store catalyst powder so that we may test it in future without any performance loss?
I am doing work on non-precious metal catalyst for ORR. All the times, I get narrow peak using CV while a broader peak using LSV for the same catalyst (as shown in the attached figure) at same scan rate, quiet time and sensitivity. I think I should get same peak potentials in CV and LSV for the same catalyst. So, why I am getting this difference in peak potentials?
I've been thinking about how to simulate the cyclic voltammogram for electrocatalytic reaction (such as HER, ORR or formic acid oxidation).
I've read some papers on the subject, but what I've found is really confusing:
On one hand, there are plenty of works done on simple electron transfer reaction (e.g. Prof. R. G. Compton), they've used the electrochemical kinetics as the boundary condition for solving the diffusion equation.
On the other hand, M. Janik and Rossmeisl et al. have used DFT to calculate the CV for OH adsorption on Pt(111) and other surfaces. But they didn't use diffusion equation at all.
So I wish to start a discussion about what processes that must be considered in modeling the CV curve for electrocatalytic reactions? I think this is a very important topic in electrochemistry (especially in electrocatalysis since CV can tell us a lot of information) and wish to hear as many responses as possible.
Hope we can move the field forward by combining our wisdoms.
Thank you all.
When using a graphite rod as a counter electrode, I find that over the course of an experiment the graphite dissolves and discolours the electrolyte (thus contaminating it). What is the best way to prepare and use a graphite rod as a counter electrode such that this does not happen?
The electrolyte I am using is 1M sulfuric acid. I also observe the same issue in 0.1M KOH.
Where possible please provide literature references.
I am working with noble-metal selenide for electrochemical hydrogen evolution reaction in acidic medium. Using DFT, I found that Se sites are active towards HER. I want to prove it experimentally by blocking the Se site selectively and without affecting the metal sites. Is there any way to block the Se sites?
As the title described, I was asked for changing the Pt wire to carbon rod as COUNTER ELECTRODE for OER process.
In my own opinions, if using Pt as CE, the dissolution and deposition of Pt will enhance the HER process, especially in acid electrolyte. However, it does not happen for OER process in alkaline electrolyte. Besides, some researches showed that Pt is inert for OER process in alkaline electrolyte. But for carbon rod, in my experience, indeed the carbon rod will partly dissolve thus might deposit on working electrode, leading to the coverage of active sites.
Thanks for your answer in advance.
While use the pseudo reference electrode, internal reference need to introduce. In the non-aqueous electrochemical system, ferrocene is most used in literature.
However, in aqueous system, pseudo reference electrode and internal reference are barely mentioned. Is there any good way to find an internal reference species?
thanks a lot
Development of new electrocatalysts for HER/OER with intended use in water electrolysis is a very active research area. The main motivations found in vritually every research article on these topics are green energy production and off-peak energy storage, and the main goal is to produce a cost-effect alternative to Pt. But the main limitation to large-scale production of hydrogen from water is high costs of electricity. Water electrolysis has been for long an established technology, and only costs of electricity limit its wider use. As of 1995, less than 0.5% of H2 was produced from water electrolysis, around 4% was produced from brine electrolysis (i.e., H2 is by-product of chlorine production), and the rest was produced from hydrocarbon (fossil) sources by steam reforming. Catalysts for alkaline water electrolysis are based on relatively cheap earth-abundant elements (Ni and Fe), and not Pt. Energy efficency of alkaline water electrolysis with this cheap catalysts is around 75--85%, which is high. Even if better catalysts are developed, this will raise the effeciency maybe by few more percents, as there are many other factors, apart from HER/OER overvoltages, that limit the efficiency.
As I can understand, these researches are driven by mostly academic interests rather than real-world applications. I would appreciate if you get involved in this discussion.
I have been working with oxygen reduction reaction (ORR), using Pd nanocrystals. I found that the in my case, the half-wave potential observed in the reverse scan (1.0 V vs. RHE while sweeping from more –ve potential to less negative potential) is better than in the forward scan (0.9 V vs. RHE). However when I do chronomperometry, I observe a value corresponding to the forward scan. I have not been able to find any literature justifying which scan value should be reported. Can anyone please advise or guide to the right literature. Thanks.
My enquiry is about any chemical/electrochemical species maybe ions or gas, etc. that adsorbs on Pb surface exposed to that species.
Currently, I am studying the electrocatalytic activity of transition metal oxides like NiCo2O4 for oxidation of methanol. The electrolyte used is 1M KOH and added 0.5M methanol to see the activity of NiCo2O4. I used GCE, Ag/AgCl, and Pt wire electrodes. But, most of the time when I repeat the CV experiment with the same condition the next day, I don't get the peaks or get very weak peaks. What is the possible reason for this type of inconsistency?
To conduct electrochemical CO2 reduction experiment, How can I convert Ag/Ag+ reference electrode to RHE reference electrode? To convert reference electrode value, I want to know pH of 1M TBAPF6 in MeCN solution. I would be grateful if you could tell me the correct way.
When a Bimetallic pair such as Au-Pt comes in contact with an electroactive species, a potential is induced between the electrode surface and the far-field bulk, I have successfully applied techniques such as CV, LSV and chronoamperometry to study the diffusion and reaction kinetics.
But I'm more interested in studying/measuring the induced potential in relation with surface reaction (Damkholers number) when the bimetallic system (Au/Pt) acting as a complete circuit, comes into contact with an electrolyte e.g H2O2.
I'm thinking about Open circuit potential (OCP), but are there other techniques I can use ?
I want to know the comparison between rare earth and transition metals for use as an electrocatalyst. There are many papers which describe that rare earth can be used as electrocatalyst but none of them describe the role of rare-earth. Can anyone please share some papers relating to the chemistry of rare earth for electrocatalysis.
I tried several catalytic ink recipes using PVDF in NMP and Nafion as binders but I had problems such as cracked electrode and losses of material. My catalytic ink containing polypyrrole.
I was trying to deposit a powder sample onto an electrode and to test its electrocatalytic reactivity. I tried to suspend the powder sample in EtOH and then drop cast this ink solution on the electrode surface. However, I noticed a low electrical current during the CV measurement and I think this is because of the gap between the powder and the electrode surface. Also, I noticed that even the powder sample is physically adsorbed onto the electrode surface, the powder sample is easily detached from the electrode surface. Is there a better way to deposit this kind of powder catalyst onto the electrode surface? Thanks for your suggestion.
When the ORR catalyst i synthesized gives five times greater current density than the commercial Pt/C, then the slope of the KL plot for the catalyst synthesized will be higher because of the higher density. In Kouetcky-Levich equation all the parameters except slope are constant as i used the same electrolyte. So when i calculate number of electrons transferred i am getting wrong answer. Can someone help me with this problem.
I am trying to determine which parameter (current or voltage) is more important for electrochemical hydrogenation. I understand that current is directly related to the rate of electron flow but the voltage at the applied current also determines how the reaction proceeds. Essentially, I want to know that when to determine which parameter is more important for hydrogenation from a CV.
I am studying a nickel based catalyst for water oxidation. While performing chronoamperometry in 1M KOH, I apply 1.6 V vs RHE and probe the current. The value of current is 10 mA initially and gradually decreased to around 4 mA in 3 days. I thought this is because of degradation of catalyst. However, when I replenish the KOH in the cell with the fresh one, the current restores to its original value (nealy 10mA). What may be the reason behind this?
Thanks in advance.
I synthesized S-doped graphene as a cathodic catalyst for Oxygen Reduction Reaction (ORR) in Microbial Fuel Cell. I also measured ORR activity using Rotating Disk Electrode (RDE). However, RDE results were not well correlated with MFC performance. In RDE, the electron transfer number (n) of S-GN was 2.67, Pt/C was 3.7. But the performance of S-GN in MFC was higher than Pt/C. Did anyone observe the same phenomenon? What are the possible reasons for that contradictory?
I'm working with choline-based ionic liquids where the anions differ from: acetate, hexanoate, isobutyrate and propionate. I analyzed the contact angle using water droplet and obtained increased contact angle in the order i described the anions. How can a relate the contact angle with hydrophilicity (all angles were below 90º)?
Thanks in advance :)
Recently, we studied some common electrolytes (LiTFSI in DMSO or TEGDME) in Li-O2 batteries and found the resistance of the whole cell is a bit large. We believe that the resistance is mainly from the electrolyte. Therefore, we would like to ask other researchers' help on the high conductive electrolytes? Thank you.
I have been trying to measure extracellular hydrogen peroxide in basic MEM using electrochemical means. I have been inducing a mimetic state of hypoxia using cobalt chloride hexahydrate and have been struggling to assess the quantity of hydrogen peroxide in my sample. I have ran a calibration using my cobalt standard in blank MEM, spiking with H2O2 and measuring via amperometry. I have found that a cathodic spike/ peak occurs but does not step like classic amperometric measurements. The change in current almost immediately returns to baseline.
I am under the assumption that this may be due to the peroxide acting as a catalyst to CoCl2, and the peroxide is being oxidised. Can someone either confirm or shed some light on this issue.
Last year i researched carbon felt electrode heat treatment of modification method in vanadium redox flow battery... So.. In this year.. I want know about new modification method of carbon felt electrode in Vanadium Redox Flow Battery....
If you have do that, advice for me a lot.....
My fuel cell shows a smooth ohmic polarization. However, my iE curve has teeth-like or spike-like shapes between 0.2V to 0.4V. Besides flooding, what else can cause this behavior?
I am trying to get distribution coefficient and dissociation constant of tetrabutylammonium sulfide in phase transfer catalysis. I could get tetrabutylammonium bromide values. but still trying to get these constants for tetrabutylammonium sulfide.
The slop is defined as delta Y divide by delta X (change in Y axis/change in X axix).
So in order to have a low slop the change of Y axis must be low as compared to X axis and vice versa. In case of Oxygen evaluation reaction (OER), Tafel slop is the change of delta V (y axis) divided by change of Log (current density), so if the change in delta is low as compared to current density the slop will be low. And if we talk about the V(x-axis) vs. current density (y-axis) graph for OER, the slop of line is high if we have big change in current density as compared to potential, and this high slop will be low if we plot it with Log (current density) on (x-axis) vs potential on y-axis. Therefore, its means that the material with low over potential should have low Tafel slop, but in literature the peoples chose the region in such a way that either their over potential is good or bad but their Tafel slop is very good, if so then why it’s very important???
If I have observed a faradaic efficiency of 93% and more, is it still necessary to deduct?
I have been asked to detect the redox current contribution from the OER current by calculating faradaic efficiency as my catalyst have shown a strong redox behaviour within the experimental potential window. But I don't find any standard reference to do so.
Thanks in advance.
I was trying to find a way to accurately report the onset potential but could not come across any accurate definition of when how to report it. The most conveniently way I came across was to report when a non-zero (anodic) current starts to flow. I'm currently investigating doped and non-doped CuWO4 for water splitting applications. For the non-doped sample, the photocurrent is higher the dark current at zero photocurrent density, But for the doped sample this is not the case. Why is happening? Am I measuring the onset potential incorrectly?