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Catalysis - Science method

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I am confused between the meaning of loaded and supported catalysts. Are these two terms same or different?
Please clarify my doubt.
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Hello guys
I'm recently going to submit manuscripts to the Nature catalysis or Nature chemistry. To protect the novelty of my idea, I decided to submit my manuscript to the preprint server arXiv or ChemRxiv. Here are some questions I have.
Is there any needs to publish my manuscript to the preprint first?
Does Nature catalysis or Nature chemistry accept the preprints?
And the Nature website writes that 'Nature Portfolio journals encourage posting of preprints of primary research manuscripts on preprint servers of the authors’ choice, authors’ or institutional websites, and open communications between researchers whether on community preprint servers or preprint commenting platforms'. See pic (Question_1_20220625.jpg)
What does the Nature Portfolio journal mean? It stands all the journals of Nature?
Does it mean that Nature catalysis or Nature chemistry accept the preprints?
Thank you a lot if you would do me a favor.
Many thanks.
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The short answer to your question is yes. A Nature Portfolio journal means indeed that the journal is part of the portfolio of what used to be known as Nature Publishing Group (NPG) Nature Research. Here you find the list of all the journals belonging to the Nature Portfolio: https://www.nature.com/siteindex The journals Nature catalysis and Nature chemistry are included.
Best regards.
PS. The link to the Science paper about preprints is an interesting read, see enclosed file.
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I have been reading a lot of papers on either side of the spectrum but have been finding it difficult how to understand which is which.
Can someone post a review or book or any piece of the written document as to how we can differentiate the two of them concerning photocatalytic reactions?
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The type-II heterojunction is the conventional mechanism which describes that, upon irradiation electrons of both the semiconductors (in the photocatalyst) get excited to the CB leaving holes in the VB. Then the lifetimes of these photogenerated electrons and holes are extended because of the shifting of electrons in the CB of the semiconductor with a more negative CB band edge to the CB of the semiconductor with less negative CB band edge and similarly holes will shift towards less positive VB. So, this prevents the recombination of electrons and holes.
In the Z-scheme mechanism, there are donor and acceptor terms involved.
Basically, in this mechanism, photogenerated electrons in the CB of the semiconductor with less CB band edge recombine with the holes in the VB of the semiconductor with less positive VB band edge. Thus, unwanted electrons and holes recombine and this enhances the lifetime of strong photogenerated electrons (in the CB of semiconductor with more negative VB band edge) and holes (in the VB of semiconductor with more positive VB band edge) which will subsequently take part in the photocatalysis.
This is the basic difference.
Yu et al. have explained these mechanisms in detail in their paper. (10.1016/j.chempr.2020.06.010)
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I have been working on acidified silicas and found that bare mesoporous SiO2, when refluxed in 12M HCl, is apparently very active in the reaction I'm looking at. With further testing on the original material that sparked this further study, catalysis is heterogeneous as the reaction does not continue upon catalyst removal. I've searched literature and found references to SiO2-Cl, but this is usually prepared with CH2Cl. Does anyone have any idea what this could be?
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Even though I have used very little concentration of p-NPA, saturation has not been attained for 5000 seconds. But researchers have done a kinetics study of peptide catalyst with the same concentration of substrate i.e., p-NPA (that I am using for my work), and monitored catalysis for 400 seconds. But, I am unable to attain saturation even within 5000 seconds for 0.2 mM, 0.4 mM, 0.6 mM, 0.8 mM, 1.0 mM and so on. So, if saturation is not attained, then how to calculate the value of Vmax, Km, Kcat? Can anyone kindly suggest to me, if I am doing anything wrong at any step? It would be really helpful.
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@Kalpana Kumari...
Everything seems to be right...
What kind of model you plan to use...to find Kcat and all?
One way is to use Michaelis-Menten equation to determine the Km and Vmax...
How do you calculate basically?
One more thing...at what temperature and how much time(maximum) you wait for it?
If something you feel confidential...you may directly message me.
Thanks and regards,
Aadhityan A.
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I have a system of a protein co-complex which behaves like a polymerase. One of them recognises the binding site and other catalyses the reaction.
I am confused between ff14SB and PARMbsc1. What should I use ?
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Dear Hindol,
For force field parameters you can use ff14SB for protein and PARMbsc1 force field is for Nucleotides(DNA and RNA).
It would help if you incorporated both the force field parameter.
Using the PARMbsc1 force field shows good agreement for the experimental results.
Please look amber-20 force field manual and especially "Molecular mechanics force fields".
Also, look at "https://www.youtube.com/watch?v=iQThYDiJs7c&ab_channel=CHARMM-GUI" choosing the force field paramter.
Hopefully, it will help.
Best Regards
Aashish
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I synthesized sapo-34/zsm-5 composites via seed induced method, and some of my samples turn to gray after calcination . I calcinated all the samples at 500C and for 5 hr. Does any one know that which factors may be the reason of this problem?
many thanks in advance
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If organic SDA was used, there is always a trace of carbon remaining after calcination. This gives it the Grey color. It does not take much to give zeolites color. So, good news is that slight color would likely not effect performance.
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1. How does oxygen concentration/saturation in electrolyte plays an important role in ORR reaction?
2. What will happen if the oxygen concentration/saturation is less in electrolyte?
is the onset potential of ORR activity or current density may fall down? if yes means why?
please attach any related literature...
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Oxygen saturation means the concentration of oxygen in solution at given pressure of O2 in the gas phase. This is called a solubility of oxygen. "how exactly the oxygen concentration can affect the ORR activity?" I would expect an increase of the reaction rate with an increase of oxygen pressure in the gas phase.
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We are using the Nafion binder for the preparation of catalysts inks for electrochemical studies. In which way the Nafion can protect the catalysts layer from the electrode surface? what will be the mechanism taking place there?
… Read more
Answer this question
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Thank you Bezzi Hamza
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Can anybody share a comprehensive study on the comparison of light sources (lamp name with power value, manufacturing company, and associated wavelength range) with that of photocatalytic performance. However, sharing the comparison with sunlight is highly encouraged.
Sharing of general opinions by field researchers are warmly welcomed, positively.
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Dear Iqrash,
There are many, many options. Personally, I recommend high pressure Xe arc lamps. They are not cheap, but they simulate the solar spectrum well. Of course, it will depend on the application to be done and the budget, but this is a good option. Eventually, for visible radiation only, conventional lighting LED lamps can be used, which also work well and are very cheap. You can see the first ones (high pressure Xe arc lamps) in the following link:
Best,
Fran
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Dear all,
I'm gonna start my PhD project as a Chemical Engineering PhD candidate. Recently, my supervisor proposed the general topic of "Single Atom Catalysis (SAC)" for my project, in order to search and evaluate.
First of all, is it a cutting edge technology approach and a novel topic to work on? Does it have any industrial potential?
If yes, please guide me through the challenges and specific areas of this topic to work on.
Thank you very much in advance
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this is a very tricky question. I would not say these materials are novel as there have been a lot of studies exploring both the electronic structure and the catalytic activity of these materials. Now the key question is what your study can add to the field? If your study is focusing on solving a particular challenge associated with the industrialization of these materials, being a new synthesis method or improving their stability in harsh reaction conditions then you are on the right track.
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We are applying 600VDC to a dielectric barrier discharge (DBD) reactor with a nickel electrode and CO2 and H2 as reactants to produce CO and H2O. Argon is added as internal standard. The reactor is made of fused quartz and the counter electrode is a silver coil around the tube. The current observed is 20-30 microamperes when the nickel electrode is set to -600VDC. Since the voltage is not high enough to produce electrical breakdown, can we assume that dark discharge plasma is responsible for this behavior?
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refer to my paper of cold fusion.
metal surface potentian need to be positive for the cold fusion.
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I have done photodegradation study for my catalyst using Rhodamine B. The amount of catalyst and dye was 0.05g and 0.05milliMolar respectively. But the UV-Vis spectra is not coming in proper way as shown in the image. At 1mM dye concentration I am getting nearly decreasing peaks. What would be the possible optimization methods of getting good response
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Did you use a syringe filter to separate the catalyst from the liquid phase? If so, it is possible that there was a leak in the filter. Elevation of the baseline might be due to light scattering coming from some solid that penetrated the filter.
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Suggest some user friendly software for making graphical abstract using Smart Arts (other than Microsoft PowerPoint).
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For graphical abstracts, I recommend you the top software, PowerPoint, Inkscape, and Adobe Illustrators. You can also improve your graphical abstract by using other free online software:
2. Biorender (https://biorender.com/)
3. Mid the graph (https://mindthegraph.com/)
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I have been convinced by the concept of direct desulfurization of crudes. The commercial development in this technology will help ridding off the require the of mutilpe reactors with different ranges of Catalytic beds in the modern petroleum refinery.
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Ahh Bugs replacing refinery process again. A 50+ year old dream that will probably come true some day - but probably not in my lifetime.
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Please suggest a method to determine this practically. Please avoid mentioning the publications having the final results. The guidelines or procedure for measurement is required. Any related discussion or fruitful comments are warmly welcomed.
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It can be calculated from UV data of photocatalyst as well as DRS data of photocatalyst. While using UV data Tauce's equation is used. While in other case kubelka munk equation is ised
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Sample solid powders of TiO2 and TiO2 with some other metal oxides.
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Microsoft excel sheet required.
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In this article they said: (( According to Figure 4a and 4b, the Ru/RuO2@N-rGO possessed the highest OER performance, requiring the smallest overpotential of 255 mV to achieve a current density of 10 mA cm−2. )) in alkaline media ( KOH 1M ) and (( The electrocatalytic performance of Ru/RuO2@N-rGO in acidic solution (H2SO4 0.5 M ) was also evaluated for OER. A relatively low overpotentials of 234 mV (OER) were found at 10 mA cm−2. ))
Electrochemical water splitting:
Reduction at cathode: 2 H+(aq) + 2e− → H2(g)
Oxidation at anode: 2 H2O(l) → O2(g) + 4 H+(aq) + 4e−
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Sina Safavi You are correct that " the oxidation state of the transition metal and transition metal species forms in solution are depend on PH and concentration of the metal salt solution." " Are you leading me to this concept?" Yes
When you are looking at overpotential of OER, you have to keep in mind the second half reaction, HER. The potential required for water splitting is pH independent, 1.24 V. In alkaline medium you have lower overpotential for OER but higher for HER
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Hello everyone,
I am interested in catalysis research and development opportunities. When I was looking at my options, I saw there's an emerging niche field of finding new catalysis through machine learning.Is anyone doing anything like this currently?
Can anyone suggest options on how to approach this effectively? Like how to start ? Googling this was overwhelming.
Any help will be appreciated.
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Dear Omkar, this is a very interesting technical question. In this context please have a look at the following potentially useful articles which might help you in your analysis:
Machine Learning in Catalysis, From Proposal to Practicing
This is a so-called "Mini-Review" which will certainly provide you with a valuable initial overview of the field. The good thing about this review article is that it has been posted by the authors as public full text on RG. Thus you can freely download it as pdf file.
Please also have a look at the following relevant paper:
Enabling Catalyst Discovery through Machine Learning and High-Throughput Experimentation
Unfortunately this paper is not yet accessible as public full text on RG. However, you can easily contact the corresponding author directly via https://www.researchgate.net/profile/Jochen-Lauterbach and request the full text from him. Perhaps he can also answer other questions you may have.
As you can see, it often pays off to search the "Publications" section of RG directly for helpful literature references.
I hope this helps. Good luck with your work and best wishes, Frank Edelmann
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Dear Scientists,
Hoping all you are fine.
I need to know if someone can recommend me how to know if Al extracted from a zeolite is extraframework or of the framework? (Other technique than NMR of Al)
In Colombia it is complicated to perform NMR of solids and we need to know that data.
Open also to collaborations.
Thanks a lot,
With kind regards,
Julián Sánchez.
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Thanks al, for the response please help me I need Complication Neonatal framework
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MSc III sem physical chemistry practicle .
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Généralement les réactions d'oxydation sont lente
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Hello, fellow researchers!
Can you all tell me what is SPSS and how to use it in nanotechnology-related research? particularly in catalysis chemistry and functional nanomaterials.
thanks a lot for your guidance and time!
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Hi,
SPSS is a program for statistics. You can use different statistical methods or tests on your data to get statistical relations (ANOVA, t-test, Tukey's test). You can also make the basis for your experimental part/conditions for your experiment via SPSS by orthogonal system.
This was just a short description, please feel free to check also the book by Andy Field: SPSS.
All the best
Patricia
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Hello, everyone !
I am looking for information on the operation of a catalyst in complex form based on stannic oxide / catalysis composite
sulfuric acid allowing the condentation reaction to form allantoin.
I put so attached the original patent and translated into English.
Thanks for your help
best regards,
Thomas
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Hello Thomas, many thanks for sharing this very interesting technical question with the RG community. When you take a closer look at this patent, you really wonder if the inventors / researchers knew what they were doing. I think that nobody knows what the composition of this "catalyst" is. It is quite a weird mixture and reminds me of alchemy. It's not surprising that the authors do not provide any formulas. In the end, the goal of this invention was the synthesis of allantoin from glyoxylic acid. This can be much easier achieved by the reaction of glyoxylic acid with urea as shown in the attached Scheme wich was taken from the German Wikipedia entry on "Allantoin". Thus you don't need to be ashamed when you have no idea what's going on in this catalyst preparation. I have no idea either! 😎
Good luck with yopur work and best wishes, Frank Edelmann
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It is well known that flavin dependent oxidoreductases do not usually release their coenzyme/cofactor after catalysis, in contrast to what happens for NAD(P)-dependent enzymes (dehydrogenases and reductases).
One colleague put forward the reasonable hypothesis that the 'stabilized radical' forms of, e.g., FAD are inherently dangerous for the cell, so that it is convenient to keep them confined in an enzyme's active site (NAD/NADH would not form such radicals).
As far as you know, there are other hypotheses on why that is?
And in case, are you aware of there having been any experimenta approaches to test such hypotheses?
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Hi there,
It might be because they act most of the time in electron transfer between donor and acceptor.
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Hello,
I want to start experiments using sulfate AOPs. In many papers, there is used for example : 1 mM of potassium persulfate. Can ayone help me how to prepare this solution?
For example:
I have 100 mL of methylene blue (10 mg/L) solution. I want to add 1 mM of potassium persulfate. Should I add 27 mg of solid potassium persulfate and then fill it up to 100 mL with my methylene blue solution, or can I use 0,1 M potassium persulfate solution and add 1 ml of this solution and then fill it up to 100 mL with methylene blue solution ?
Thanks for answers
Juraj
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thanks for this information
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Could TOF be affected by any catalyst properties or reactor conditions? Please share more light on the choice of your answer (other than Yes/No) and if possible provide supporting materials. Thank you all.
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Thank you Sina Safavi
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I am currently trying on a synthesis involving Amberlyst-15 (polystyrene with sulfonic group at p-position) as a proton donor. When following the reaction process by quantitative 1H NMR, I am noticing that part of my (basic) reactant (2-methylimidazole) is being immobilised against the resin and is unavailable for reaction with the rest of the reactants.
Has anyone experienced this when working with similar ion excange resins?
I am trying to figure out ways to liberate it from the resin. Any suggestions would be greatly appreciated.
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Dear Trey Todor Koev thanks for sharing this very interesting technical problem with the RG community. I'm absolutely no specialist in this field, so perhaps my thoughts are a bit naive. I assume that you just have an acid-base reaction in which the 2-methylimidazole formed a tightly bound sulfonate salt with the ion-exchange resin. In this context, please have a look at the following potentially useful article which might help you in your analysis:
Anchoring a Co/2-methylimidazole complex on ion-exchange resin and its transformation to Co/N-doped carbon as an electrocatalyst for the ORR
Unfortunately this paper is not freely available as public full text on RG. However, all ten authors have RG profiles, so that it should be no problem to request the full text of the paper dierctly from one of the authors via RG.
Good luck with your work!
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What are the electronic properties
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Ru a good metal for the selective methanation of CO. it exhibits good activity due to pore size , surface area and selectivity in CO methanation.
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Hi!
I would love it if someone can explain how to read the vibrational frequency data listed in NIST website. For example, there are four vibrational modes (in cm-1) listed for Methane (https://webbook.nist.gov/cgi/cbook.cgi?ID=C74828&Mask=800), 2917 (symmetric stretching), 1534 and 1306 (both degenerate deformation), and 3019 (degenerate stretching) . Methane should have 3N-6 = 9 vibrational frequencies, so how do I know which of the above mentioned degenerate modes are doubly or triply degenerate? This website (https://lweb.cfa.harvard.edu/hitran/vibrational.html) mentions 1534 is doubly degenerate and 3019 and 1306 modes are the triply degenerate modes which makes up the 9 frequencies for methane. But it also mentions the following 12 modes for Ethane (2954, 1388, 995, 289, 2896, 1379, 2969, 1468, 823, 2985, 1469, 822) where the last 3 are stated as doubly degenerate. But that would still give us 15 frequencies instead of 18. NIST mentions almost similar frequencies for ethane (https://webbook.nist.gov/cgi/cbook.cgi?ID=C74840&Mask=800) but lists 2969, 1468, 2985, & 1469 as degenerate modes. Hence, my question is, how do I know which of the NIST listed vibrational modes are doubly or triply degenerate to make up the 3N-5 or 3N-6 frequencies for linear and non-linear molecules?
Thank you so much!
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Yes the NIST data is often a bit confusing.
You are correct there are 9 NORMAL modes of methane there's a nice animation here:
You could predict the number and degeneracy (and the atom movements) using group theory (Td point group).
Problem is when you come to experimentally measure the spectrum:
1. Many of the modes "couple"
2. Many are only Raman active. Raman and IR often show at (slightly) different frequencies.
3. Gas phase and liquid phase will have different frequencies
4. There will also be rotational excitation.
So it is often difficult to find two frequency tabulations that agree (exactly).
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How can I stabilize acetal formation in acidic medium at the end of my reaction? I trace down the ph value that reduced from 5.6 to 3 in one month. How can I keep the pH to going low wihout any NAOH neutralization.
In other words; I am looking for a way to stop acetal hydrolysis.
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Dear all, without knowing the type of acetal, one can suggest only general solutions, I suggest the following :
- if possible work under solid-state or bulk conditions
- use the Hammett equation to deduce the energetic part of the molecules, and especially the substituent effect.
- acetals are well studied and used in the protection chemistry, where their stability is of prime importance.
My Regards
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The following data are obtained in an enzyme catalyzed reaction: [S]x10^4(moldm^-3): 2.5, 5.0, 10.0, 15.0.
Then rox10^6(moldm^-3min^-1) : 2.2, 3.8, 5.9, 7.1.
Assuming Michaelis-Menten Kinetics, calculate:
1. rmax
2. Km
3. K2
Using the Lineweaver- Burk and Eadie method.
Given [E]o = 4.0x10^-6 mol/dm^3
1. rmax- maximum rate
2. Km- Michaelis Menten constant
3. [S]- concentration of substrate
4. ro- initial rate
Check the image for clarity.
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Regardless of whether we use nonlinear regression or one of the many graphical methods, e.g. L-B, E-H or Merino, nothing will change because the number of points is too small to determine reliables values of two parameters. Additional kinetic tests should be performed for rate limiting substrate concentrations below 2.5 and above 15.
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I have gone through few literature about Hansen solubility parameter and few literature about Lewis acid base interaction.
  • I found that Hansen's solubility parameter are useful for dispersion, suspension and solvation phenomenon where solute either get dispersed or solubilized in solvent to get the resultant homogeneous solution or mixture.
  • Whereas, Lewis acid base interaction are useful where solvent molecule get adsorbed on solute and stuck on it for different application like catalytic activity.
I have a confusion that whether the Lewis acid base interaction is also useful to describe the homogeneous dispersion of particle in solvent?
Please suggest me some useful literature which helps me to go with this.
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Maybe increasing or decreasing it. Please do support your comments with relevant literature, if possible. Thanks
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Actually, the apparent activation energy is that in the presence of the catalyst in this case. The suitable reactor design facilitates the mass transfer inside the reactor and consequently increases the catalyst efficiency instead of having dead zones in the reactor in the case of poor design. The net result is an increase the rate of the chemical reaction
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Hi,
I am interested in knowing ways to correlate catalytic efficiency with the hydrogel mesh size, network structure, and solute diffusivity.
Any lead in this direction will be highly appreciated.
Thank you!!
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Please check this literature it might be of help.
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I am looking to find a material (any type) that can offer me CO formation energy (> 2.0 eV) and NO formation energy ( < 0.5 eV) simultaneously. Secondly, how to confirm these formation energies experimentally? Your expert opinion in surface reaction, catalysis would be appreciated. Thanks
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Thank you Professor Frank T. Edelmann for the great insight. sure, I'll go through the mention linked. well, from your expertise, will you please suggest some potential materials which can show desired chemistry. Thanks
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In what case would a reaction rate always show direct relation with activation energy or would it always be an inverse relation? Is it a indirect relation, inverse relation or both case can hold? (Please provide supporting resource, thank you).
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Toyese Oyegoke when we are talking about your question and particularly the catalyst which always lowers the energy of the transition state for the reaction - in this case any reaction you can assume.The difference between the transition state energy and the other part that is the reactant energy is the main ACTIVATION ENERGY and this is very important to understand, Lowering of this energy which means lowering of transition state energy also ensures and lowers the activation energy for sure
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I would like to get the concept of what it is all about and relevant supporting materials would be appreciated. Thanks to you all.
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Dear Toyese Oyegoke,
I have attached some books about Surface Science and Catalysis. I hope they would be useful.
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Requirement of hydrogen as fuel directs us to utilise sea water but the computational techniques for such analysis are rare, how do we simulate the sea water catalysis using ab inito methods
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This Question which interested me a lot, thank you very much
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C1s peak at 284.8 corresponding to Adventitious Carbon is a reference for the X-ray photoelectron spectroscopy (XPS. However, when using carbon-based support, say Vulcan carbon (rich in graphitic carbon), r-GO and GO for deposition of active catalyst.
The C1s peak in these cases will be dominated by sp2 carbons, not by Adventitious Carbon.
How to calibrate the XPS data in that case?
How to account for the charging problem?
Thanks in advance
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As Jurgen states, the vulcan carbon should have enough conductivity. If using a monochromatic XPS system then analyse without the charge neutraliser on and ensure the carbon is in contact with the spectrometer (e.g. pressed in to a metallic well on the sample bar), then you shouldn't have an issue. The sp2 carbon will be ~ 284.5 eV depending on how well your spectrometer is calibrated.
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Could an electronegative support act as an electron sink to facilitate the oxidation of low-valence metal ions to higher valences?
If it could then Does electronegative support affect the catalyst efficiency in chemical water oxidation process?
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Dear Chinnaraja Eswaran I checked that link but It doesn't related to my question.
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I have a question on how would kinetics of enzyme change if mutant were made with
1) tighter binding but same catalytic rate
2) same binding but slower catalysis
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Both.
1) tighter binding but same catalytic rate
If Km decreases but kcat stays the same, the rate increases, but this increase may be negligible if [S]>>Km.
(except that I replaced tighter binding with lower Km, which isn't quite the same thing)
2) same binding but slower catalysis
If kcat decreases but Km stays the same, the rate decreases in direct proportion.
(lower kcat represents slower catalysis)
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In particular, areas/issues that have potential to be of national/international importance.
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Energy storage...batteries are a very hot topic at the moment (but also thermal energy storage). Smart-grids may attract interest as well. Last but not least...energy management through AI.
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In attached Review article registered that in mononuclear
Ru-based WOCs hydrophilic/hydrophobic properties act as a barrier for coupling process of two radicals during water oxidation without any explanation about that. Now here is the question How can hydrophilic/hydrophobic properties affect the radical coupling process in WO's molecular catalysts? Is there any relation between hydrophilic/hydrophobic properties and radical coupling process ?
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The review is relatively old. Much has been done for the last 4 years. The mechanism is highly speculative. I disagree with authors on numerous aspects. I think that there is no much sense to discuss details of unproven mechanism.
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I want to deeply study one reaction can produce oxygen from Carbon Mono/di Oxide..
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CO2 can be converted to CO and O2 via a dielectric barrier discharge (DBD). There are several published papers in this regard -- 'CO2 conversion in a coaxial dielectric barrier discharge plasma reactor in the presence of mixed ZrO2-CeO2'
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Hello,
Recently I have been attempting to synthesize graphitic carbon nitride for the purpose of photocatalytic conversion of carbon dioxide to methane under visible light.
The issue I am facing is that all my samples are greyish in color, rather than yellowish, and I believe the yellowish g-CN is needed for photocatalysis in the visible spectrum.
Has anybody faced a similar issue or could provide me with some insight as to why this is happening and how I could possibly improve my g-CN?
I have attached pictures of the samples I have obtained so far:
  • Sample 1 - 50g of Urea at 600°C for 2.5H, heating rate of 10°C/min
  • Sample 2 - 15g of Urea at 550°C for 3H, heating rate of 10°C/min
  • Sample 3 - 15g of Urea at 600°C for 4H, heating rate of 10°C/min
From the literature I have read, I understood that the degree of polymerization (DP) determines the final band gap and color, and the DP could be varied by the temperature and time, and the precursor. This is why I performed the synthesis of sample 2 and 3 (one being 550 for 3H and the other 600 for 4H), but as you can see in the pictures, they appear to be more or less identical.
The FTIR graphs of these samples, all have the characteristic peaks for g-CN, but I have not been able to perform an XRD analysis yet.
Another related question I had is - Does the crucible material influence my product in any way? I am using a porcelain crucible.
Thank you,
Joshua Nigel
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Dear Joshua Nigel Fernandes many thanks for your interesting technical question. In general I think that your samples look quite all right, especially the first two. As suggested by Raja Preethi V it might be worth a try using melamine as starting material. For more information about this please alternative method go through the following relevant research article in which a simple high-yield synthesis of g-C3N4 for enhanced visible light photocatalytic activity is reported. I think it's important to exactly follow the heating and cooling rates described in this study:
One-step, high-yield synthesis of g-C3N4 nanosheets for enhanced visible light photocatalytic activity
You can also easily find and access relevant papers on this topic by using the "Search" function of RG. For example, look for the term "g-C3N4 synthesis" and then click on "Publications":
Numerous papers on this topic have been posted on RG, some of them even as public full texts.
Good luck with your research and please stay safe and healthy! 👍
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water splitting
Graphitic layer
metal
electro catalysis
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Amravati Singh Now every things completely change. You said: if metal coated with graphite layer and it means core-shell structure. Well I must explain the mechanism of the water splitting reaction for you if you are asking about metal-doped graphene catalysts. We have two half reaction in water slitting prosses:
1) 2 H+(aq) + 2e− → H2(g)
2)2 H2O(l) → O2(g) + 4 H+(aq) + 4e−
The oxidation reaction is the bottleneck of the water splitting prosses. The metal doped graphene act as a catalyst for the oxidation reaction. The metal oxidize by light or electricity or chemical oxidant like CAN and metal loses electrons and holes are formed. Now the metal site is ready to accept the H2O or OH- as a ligand. Then a radical coupling or water nucleophilic attack occurs that forms O2(g) and the metal reduce to the former oxidation state.
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Hi everyone, I am investigating the adsorption of an alcohol molecule over a SrTiO3 cluster model, using Gaussian16 software and the DFT functionals: PBE, TPSS and B3LYP. The cluster has 60 atoms and two layers. Both optimization and single point calculation with B3LYP functional works without any problem, but with PBE and TPSS functionals does not, because SCF not converge for both types of calculations at the same conditions for B3LYP. My questions are: What could be the cause of this problem? What do I need to solve this?.
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You can try the following:
1. Take the B3LYP chk file and read the wfn and geometry. This would serve as a good starting point. You can do this by making a copy of your chk file and adding keywords such as geom=check guess=read to your root section.
2. If the above does not give SCF convergence, then start with a slightly smaller convergence criteria using SCF(conver=5). Later you can make it into default.
3. There are different algorithm realted options available for the SCF. You can explore, for instance, QC, XQC, etc. For reference, check : https://gaussian.com/scf/
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In a review entitled Frontiers of water oxidation: the quest for true catalysts from G. R. Patzke and coworkers registered that the hydrophilic/hydrophobic properties act as a barrier for coupling process of two radicals during water oxidation without any explanation about that. Now here is the question How can hydrophilic/hydrophobic properties affect the radical coupling process in WO's molecular catalysts? Is there any relation between hydrophilic/hydrophobic properties and the radical coupling mechanism ?
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Dear Yuri Mirgorod I don't critic your answer. I'm just paying your attention to the original question, which is about water oxidation half reaction mechanism. No membrane, no hydrogen evolution, not necessary electrolysis.
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Environmental factors, inhibitors, redox or pH-conditions.
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How about conducting the reaction at low temperature in ice-bath.
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Hello,
I observed negative nonlinear effect during development of enantioselective reaction and %ee product vs %ee ligand curve has local minimum: there is aprox. 10% ee of product when the %ee of ligand is 10 and 65%.
It might as well be an experimental error but I suspected that there might be two different pathways involved, could this explain the minimum? It seems that literature examples dont have any local minimum if the nonlinear effect is observed.
thanks
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Dear Michal Kriegelstein thank you for your interesting technical question. For more genera information please have a look at the following potentially useful article:
Nonlinear Effects in Asymmetric Synthesis and Stereoselective Reactions: Ten Years of Investigation
This article is freely available as public full text. Also please see the attached closely related article.
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Influence of ligand on an heterogeneous catalyst surface reactivity
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Thank you for sharing idea Madhukar Baburao Deshmukh
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I am over-expressing CYP P450 reductase in E.coli and want to use whole cell system for determination of P450 reductase concentration.
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Do you figure it out?
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I have several question regarding the MOR; hope anyone help me better understand.
1- in CV using (KOH+MEOH) what is the indication of absence of the redox peaks? shouldn't they exist as a sign that the electrode is being regenerated and able to carry the MOR?
2-why some papers don't operate in potential windows to reach the Methanol Oxidation peak and they use the onset potential as an indication to MOR? isn't important to know where the peak is?
3- what is the indication of the area under curve in Cyclic voltammetry (large vs small) for both (KOH alone) and (KOH+Methanol)
any resources are very appreciated.
Thank you.
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Generaly, the absence of peak means that methanol is not electrochemically active under the conditions of your experiment such as potentials window, scanning speed, pH, temperature...
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Definition of catalyst
Definition of catalysis is: "By catalysis is meant the change in the rate of a chemical reaction under the action of substances that do not change chemically as a result of the reaction. These substances are called catalysts".
Now we will consider two examples taken from the literature. To prevent you to fall into the usual prejudices, we replaced the names of individual chemical components with codes E, X, Y and Z.
Example 1(a): "X/Y was the first ... used for E polymerization. The ... activity decayed rapidly due to reduction of X so X/Y has a very poor activity. By using Z in place of Y, it was observed a 1000-fold increase in E polymerization activity". Similarly, example 1(b): "X in combination with ... Y ... are indeed capable to polymerize E, but only at very low activity. Only with the ... application of Z ... it is possible to enhance the activity, surprisingly by a factor of 10000".
Question: Having in the mind the definition of catalysis and the behavior of components E, X, Y, and Z in examples 1(a) and 1(b), what is the catalyst: E, X, Y, or Z?
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In the strict sense of the definition, neither X, Y or Z are the catalysts. The species that's bringing forth the desired effect (acceleration of the reaction rate) and is not ending up among the reaction products, is probably something being generated from X and Y (or X and Z). This species should be called "catalyst" and X, Y or Z are often desgnated "precatalysts". Precatalysts have to be "activated" to perform as catalysts, ususally this occurs in the course of the desired reaction.
Exploring the nature of the true catalyst, the active species, is a tedious task in many cases, and often this species is unknown. Nevertheless, a careful use of the appropriate terminology is desirable.
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where K(subscript)On is the rate of Enzyme (E) + Substrate (S) going to Enzyme-Substrate complex (ES).
I think I understand why K(subscript)Off and K(subscript)catalysis have units of time^-1. They're going to be multiplied by a molar amount of ES, so you end up with mol/time, which makes sense as a rate, right? But then why isn't this the case for K(subscript)On? If moles are also in the denominator, they will cancel when multiplied by a molar amount of an input, leaving just time^-1 as an output, which I'm not sure how to interpret.
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kon is a bimolecular rate constant. The rate law is rate = kon[E][S]. Since rate is molar/second and [E] and [S] have units of molar, the units of kon have to be molar-1second-1 so that when you multiply by molar2, the units of rate work out to be molar/second.
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Any significant progress in the design or innovation of solid catalyst for biomass hydrolysis and sugar fermentation into alcohols in a biorefinery? If yes, I would like to have some recent updates regarding that subject. Thank you all
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Thank you for your answer,
Pedro Nakasu
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A manuscript I worked on is going to be submitted in Nature Catalysis. I am currently trying to apply for a scholarship and a I am hoping that the paper get published before the application deadline so I can add it to my resume.
So if anybody knows, how long does it take Nature Catalysis to review a paper?
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Once I know for sure I will share if the paper get accepted or not and how long it took Nature Catalysis to review it.
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Could the presence of ligand on a catalyst surface reduced the reactivity of its surface? If yes/no, please explain why?
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this depends on which type of ligand used
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Generally speaking, in serine proteases, the three residues of the classic catalytic triad each have a specific role in the catalysis. There are a bunch of examples showing that mutant of His to Ala abolish the activity of an enzyme. However, in some papers, a mutant of His to Ala remains a little activity (very small compered to WT). I read one of these papers and found an example: "H157A had only 5.8% of the Kcat activity..., which supposedly performed catalysis aided by a water molecule in the active cleft". I wonder if the water molecule can do that or something else happen in the pocket of this enzyme?
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The molecular mechanism of Ser-proteases is explained in many biochemistry textbooks; I have done so in chapter 5 of my "Fundamentals" (doi:10.1007/978-3-319-19920-7_5).
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I would like to know the difference between the turn over frequency, rate of the reaction and the activity of the catalyst?
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(TON) number of moles of reactant consumed/(mole of catalyst TON/time of reaction.
Turnover frequency (TOF) = Turnover number/ time of reaction. Hence , TOF indicates the activity of a catalytic centre for the reaction
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i am doing a project in the catalysis of silver nanoparticle...
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While we use TiO2 as the catalyst to do some chemical reaction, we could use themo or photo as the engergy input. In fact, conventional thermal catalysis process was normally explained by the acid or base site of TiO2 based catalyst while also the temperature could induce the internal electron-charge seperations of semiconductors. How to think about why one catalyst (semicondutor) could use two theory to explain its role during the catalysis process? How to clasify?
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Heat causes to release the electrons in a conductor becuase of very low bandgap but in a semiconductor such as TiO2 we nead higher amount of Q and it can change littice structure of TiO2 from anatase form to inactive rutile phase.
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I use Packmol to create xyz file for slab-water interface, and was able to perfectly view it with jmol. However, after I insert the xyz coordinates into POSCAR file that contains the vector latices/positions and use the vtscript to create an xyz file to view the outcome, the structure obtained from packmol xyz files seems to be different. The POSCAR files seem to be distorted.
To understand what I meant, I have uploaded the POSCAR file, Packmol(xyz) file and xyz file created from the POSCAR file.
Please kindly intimate me on what I have been doing wrongly.
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Matthew M. Montemore Thanks for your response. I'll consider learning ASE. Dr. Sambath Baskaran Thank you as well for the link. However, I need to create a water layer on top of my slab and not just an ordinary water cluster.
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Hello
Nitrooxy group (nitrate esters) is used in the preparation of vasodilators.
The use of silver nitrate to convert alkyl halides to nitrate esters is very common.
A. McKillop & M. E. Ford used mercury nitrate in organic media, but not repeated by someone else.
Can other nitrate salts be used to convert halides to nitrate esters?
Thanks all.
Emami, Mut orgsynth.student
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Hello Mr.Grice
Some good leaving groups like tosylate ,tms ,.. are good.(base on reported works)
But halids are relatively inert in some reactions .
Use of I as leaving group in allylic position is a Conventional method but problem is cost.
Nucleophilc replacement of NO3/X since Hughes & Ingold is Well known but other cations participation or catalysis is unkown...
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Dear Colleagues,
I’m pleased to inform you that open access journal /Catalysts/ (ISSN 2073-4344, Impact Factor: 3.444) is planning to publish a Special Issue on the topic of "Trends in Catalytic Advanced Oxidation Processes". The submission deadline is 30 March 2020.
This Special Issue is dedicated to novel achievements in the field of catalytic advanced oxidation processes. The contributions should be related to the listed topics:
· Catalytic processes in water and wastewater treatment
· Developments in Fenton-like AOPs
· Activation of Persulfates for AOPs
· Formation of sulfate radicals
· Catalytic cavitation-based AOPs (hydrodynamic cavitation and acoustic cavitation)
· Sonocatalysts
· Catalytic ozonation
· Photocatalysts—including visible light and UV applications
· Catalytic wet air oxidation (CWAO)
· Catalytic–electrochemical AOPs
· Carbon catalysts for AOPs
· Nanocatalysts
· Risk of by-product formation during water and wastewater treatment
· Developments in process control of catalytic AOPs (analytical methods, chromatographic, and spectroscopic techniques)
· Methods of catalysts characterization
· Post-process assessment of effluents toxicity
· Application of nanobubbles in AOPs
· Economic analysis of catalytic AOPs application and catalysts life cycle assessment (LCO)
· Industrial catalytic wastewater treatment
· Modelling and optimization of catalytic processes
· Green chemistry aspects in catalytic water and wastewater treatment
Detailed information regarding this issue, please follow the link below to the Special Issue website at: https://www.mdpi.com/journal/catalysts/special_issues/catalytic_aop
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In order to plan for the whole paper project, I appreciate you could inform me within three weeks as to whether you would be willing to contribute. I also encourage you to send a short abstract to me (grzegorz.boczkaj@pg.edu.pl) or to Caroline Zhan (caroline.zhan@mdpi.com) in advance.
Sincerely hope this invitation will receive your favorable consideration.
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Department of Process Engineering and Chemical Technology, Faculty of
Chemistry, Gdansk University of Technology, 80-233 Gdansk, Poland
Caroline Zhan
Assistant Editor
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Thanks for your invitation. We can contribute if publication charges are waived.
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Dear colleagues,
Software like biorender (link below) is useful to support researcher in illustrating their researches. However, maybe it is merely difficult to find an appropriate software especially in inorganic materials like catalysis reaction or nanoparticles illustration. Maybe some of you can recommend the software for this?
Thank you.
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HI,
The two software options I would suggest are Gaussian and Hyperchem. Both are usable for calculations. Gaussian is the much bigger name but both are usable for building structures and so much more. Hyperchem should be something you could get cheaper. There are some other software's out there that I have heard of but not had exposure to. That said their are some SW that are "free" but I am not sure how easy they are to work with. Also, if you can find some similar files that are close to what you want, it might be worth trying to get a copy and modify to your needs.
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Soil is a very complex and also abundant mixture. In my knowledge, some products such as clay could be used as solid acid which could be used as a catalysis. It is very interesting practice. Now, I am interested in developing useful catalysis or products from soil indirect. So, could you tell me some developed products or strategies in this respects by using one kind of soil as the starting material.
Sincerely
Xinxing
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There are several reactions catalyzed by soil(Clay). This is because of basic nature of the soil & micro-elements present in the soil.You should use dried finely powered soil for the reaction.
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How to separate two water-soluble compounds like sugar and salt/ionic liquids, what is the effective method to separate them?
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I think, answer given by Madhukar Baburao Deshmukh is right.
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Consider the catalytic reduction properties of nanometal (add NaBH4). 4-Nitrophenol (4-NP) will turn into 4-Aminophenol, however, 4-Aminophenol is still a compound with a Benzene Hydrocarbon (C6H6) which is difficult to decompose, which is still very harmful to humans. So, is this a comprehensive solution?
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Dear all, does this question of environmental concern? Find attached files that may add some information. My Regards
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We applied solar photo catalysis for the treatment of pollutants in saline water. The presence of chloride ions significantly reduce the performance. Is there any proper solution to overcome this problem?
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Thanks Quan
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Certain times, there are inert components used in a process. I am curious if there are/can be developments to convert these inerts to catalyse the same reaction?
For this research, I wanted to take a look if there are examples where a product formed in the reaction catalyses the same process, or other way put, some 'product' fed in the reaction, acts like a catalyst.
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Yes, the product of a reaction can act as a catalyst for the same reaction. It is called an autocatalytic reaction.
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I have used FTIR to measure both the gas phase CO and surface adsorbed CO (on Ni powder catalyst with Al2O3 and SiO2 as substrate, DRIFTS mode). The Ni-C bond should lower the strength of the C-O bond (backdonation theory, etc), thus lower its vibrational frequency, but we have consistently observed the opposite: the surface CO has higher wavenumber than the gas phase CO. I am wondering how could this be possible?
I have attached a graph which compare the two spectra.
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I agree with what Yuri Mirgorod has said. But, this is not quite unusual. In the case of OC:BH3 adduct also nCO goes from free CO value of 2143 to 2165 cm-1. In metal carbonyls M(dxy, dyz or dxz)-->pi*(CO) is responsible for decreasing the value. But CO bond polarization is equally responsible for nCO shifts. Please read the article: Chem. Sci., 2016, 7, 1174-1184 by Giovanni Bistoni et al. In fact, in Ni(CO)4, it is the pi-bonds (dNi-->pi*CO) are solely responsible for the existence of Ni(CO)4 molecule and not OC-->Ni sigma bonds.
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Both these phenomena are termed catalysis, but clear and complete discussion and specification of their similar and distinguishing features would be useful.
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Heterogeneous catalysis the phase of catalysts differs from that of the reactants or products. On the other hand homogeneous catalysis the catalyst is soluble forms a homogeneous mixture with the reactants . The common feature in both types of reactions reaction occurs at the surface .The rate depends upon the amount of the reactants and nature of the substrate. Sterically crowded substrates may undergo the reactions less readily in both the cases.