Questions related to Catalysis
According with the Arrhenius equation the activation energy can be estimated determining the rate constant. Why often we see Arrhenius plots with the ln (reaction rate) as a funtion ln(1/T)?
I prepared carbon materials from biomass waste. I studied preparation of carbon materials from biomass using a catalyst and without a catalyst in pyrolysis process. Catalytic pyrolysis leads to lower specific surface area, pore size and pore volume than non-catalytic process.
Please suggest some reasons.
I am about to conduct a photocurrent analysis on my synthesized catalysts, but I have no idea about the appropriate potential that needs to be applied to obtain accurate photocurrent measurements.
Hello - I've been with working with XRD and I've heard people say that increased dispersion of a metal on a support can lead to scattering away of the x-rays from the oxide lattice faces, leading to a decreased intensity of the support peaks. However, XRD is a bulk technique, and given the same metal loading, I'd don't actually see why this is true, and don't want to mention that in a paper without a reference.
Does anyone have an explanation and a reference at least for this happening, if not a reference for an explanation?
Hi everyone!! I just started my journey as a PhD candidate and my main area of research will be very related to catalysis driven either by metal or photoredox systems. Hence, I was looking for some recommendations in regard to a general book for setting the base and a good background in organometallics, plus also in photocatalysis.
Thank you very much in advance :)
I want to demonstrate the battery performance of two different configurations of electrochemical devices through simulation or any other type of calculation, but I don't know what type of simulation can help prove the experimental findings of the two devices. H-type cells and Flow type fuel cells have different performance for the same catalyst.
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?
Engine misfire is a major reason for the thermal deactivation of catalyst converter, and misfire rate of an engine is an important parameter to understand exhaust gas temperature. I need to calculate misfire rate of an engine. How to calculate misfire rate of an engine and what are the parameters are required for it?
My lab has bought an Ru/C sample which has a moisture content of about ten percent while packing. I want to know whether there is any way of reducing the moisture content of the sample before using it, in order to get an enhanced performance in water electrolysis
Many Palladium complexes dispense Pd black or other mixed phase nanoparticles when catalyzing organic transformations, whereas some do not. Why is it so? What factors affect these nanoparticle formations?
in case we said that if value of gibbs free energy is zero then it is best for adsorption so that it can be easily desorb and catalysis process is favorable and also small positive value is also take into account so my question is to what extent our positive value is good (suppose 0.2kcal/mol is good or not) while negative gibbs free energy is not favorable because then catalyst can not be desorb and catalyst will be no more available for using again
Hello everyone, Can anyone help in understanding the sqroot notation of supercell? and how to transform one supercell of a crystal system to another via vesta or any other application. I wish to transform the hexagonal unit cell of MoS2 to 9 X 4 sqrt3 rectangular supercell.
For example, Cu/Zn/Al catalyst. 0.1M, NaOH soIution use for pH maintain. Desired pH achived without completing this NaOH solution. I wonder about rest of this solution is wastage?
I am conducting esterification between acid crotonic and methanol with catalysis H2SO4. I wonder why my TLC (silicagel GF254, mobile phase:EA - n-hexan = 7:3) only has starting spot, not acid material and ester product spots
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.
Should the water be included under ligand.pdb or enzyme.pdb?
Could you please either the interactive or command line method to do so? Thank you.
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.
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?
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?
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.
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 ?
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
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...
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?
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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
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?
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
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.
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.
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−
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.
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,
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
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?
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?
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
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.
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!
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.
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:
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.
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.
Maybe increasing or decreasing it. Please do support your comments with relevant literature, if possible. Thanks
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.
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
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).
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
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
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?
In particular, areas/issues that have potential to be of national/international importance.
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 ?
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.
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?
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?.
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 ?
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.
I am over-expressing CYP P450 reductase in E.coli and want to use whole cell system for determination of P450 reductase concentration.
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.