Science topics: ChemistryCatalysis
Science method

Catalysis - Science method

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Hello everyone,
I am currently working on an exciting research project where I have prepared carbon dots (CDs) from vegetable juice using a microwave-assisted method. These carbon dots were then functionalized with appropriate materials at 70°C to enhance their surface properties for potential applications in sensing, catalysis, and biomedical fields.
To move forward, I need help finding research centers, universities, or laboratory facilities that have the necessary instruments to characterize my carbon dots. Specifically, I am looking for access to the following instruments:
• Scanning Electron Microscopy (SEM)
• Transmission Electron Microscopy (TEM)
• X-ray Diffraction (XRD)
• Surface Area Analyzer
• Zeta Potential Analyzer
If you know of any centers, universities, or labs near Oman or in the Gulf region that offer these services, I would greatly appreciate your recommendations.
Additionally, if possible, please share details regarding:
1. Pricing
2. Turnaround time for results
3. Contact details or a point of reference
I am keen to collaborate with experts or institutions that specialize in nanomaterials and advanced material characterization. Your support and suggestions will be invaluable to the success of my research.
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Kindly message for further dicussion.
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I have a material that produces hydrogen gas under certain conditions.  I need to quantify this and was wondering if it was possibly with GC-FID.  I know TCD is preferred but that is not an option at this time. 
Update: Thank you for your responses.  Would other instruments such as DSC or TGA be able to analyze for H2?
Or is there a method to convert H2 to a derivative for GC-FID analysis?
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TGA can measure the amount of materials lost during heating. However, it can not determine what are the materials. To confirm the content of the released gas, TGA-MS should be used.
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We have an original Alluaudite-Molybdate we want to test for catalysis and photocatalysis applications.
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Yes, researchers in heterogeneous catalysis and photocatalysis might be interested in testing your new Alluaudite molybdate compounds. These materials often exhibit unique electronic, optical, and structural properties that are promising for catalytic applications, including pollutant degradation, hydrogen production, or selective oxidation reactions. Collaboration with academic institutions, material science laboratories, or industries focused on sustainable technologies could be fruitful. Sharing detailed material characterization and potential catalytic pathways can enhance interest. Engaging in forums or publishing preliminary results may also attract researchers.
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what are the enzymes used in oxidoreductases catalyze oxidation/reduction reactions?
can anyone please provide refence link from where i can find the published articles regarding specific enzymes and their reactions?
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Oxidoreductases catalyze redox reactions, where the transfer of electrons or hydrogen atoms occurs between molecules. These reactions include:
1. Dehydrogenation: Removal of hydrogen atoms (e.g., lactate dehydrogenase converting lactate to pyruvate).
2. Oxidation: Addition of oxygen or removal of electrons (e.g., alcohol oxidase oxidizing ethanol to acetaldehyde).
3. Reduction: Addition of electrons or hydrogen (e.g., nitrate reductase reducing nitrate to nitrite).
4. Hydroxylation: Incorporation of hydroxyl groups (e.g., phenylalanine hydroxylase converting phenylalanine to tyrosine).
These enzymes include oxidases, reductases, dehydrogenases, and peroxidases.
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I read some scientific articles about Metal organic frameworks(MOFs) in that mostly they have reported about tunable porosity using ligand, large internal surface area, tuning the properties of MOF using different metal ions and ligands, etc.
I want to know what exactly makes this MOF materials unique in the field of catalysis?what makes this materials interesting?
looking for your valuable knowledge.
Thank you
Shanmuk
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Try to focus your attention on solid support catalysis using not only metal ions, but also (plus) active organic molecules supported on polymer resins. You can find inspiration on my profile. Try to think about it.
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Hello everyone. I have optimised the trypsin catalysed hydrolysis of N α -Benzoyl-L-arginine ethyl ester hydrochloride, but unfortunately I have not found any reference. If, someone has reference of said reaction, kindly forward it to me.
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..
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also for practical matters. although there are advantages linked to the amorphous state, from a synthetic point of view it is much more complex than obtaining a specific crystalline phase
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Here is one case: I want to perform X + Y in the presence of Z catalyst in a 50 mL milling jar with 8 12 mm milling balls and investigate whether the the amount of catalyst affect the yield of the product. So, I change the amount of catalyst from 1 molar equivalent to 3 molar equivalent as compared to X. However, this will change the total volume of powder as well. And as we all know, when the volume changes, the kinetic energy delivered from the ball to the material will not longer be the same. Less energy will be delivered to the powder and the kinetics of the reaction will be affected by this.
I've read that the milling load in a mechanochemical reaction is defined as the total powder mass divided by the void volume in the jar (jar total volume - volume of balls)
In the case I mentioned before, should I (1) keep the amount of everything the same and increase the amount of the catalyst as what it should be, basically ignoring the effect of volume and just do the experiment or (2) Readjusting the mass of all samples to keep the total mass the same as before to maintain the same milling load as before (as a result, it will decrease the mass of the reactant) ???
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One of the most important parameters in any mechanochemical reaction (ball milling) is the ball to powder ration (BPR). What I personally do and I find to give consistent results is keeping the powder volume constant (which means if I have to change the ration of 2 or 3 components I readjust it in order to keep the same BPR).
In case the amount of your catalyst is negligible compared to the total volume (mass) of the powder you can ignore it.
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biomimetic catalysis
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You definitely can learn more about biomimetic, if you read literature in this area.
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What properties determine the ability of different valence metals to adsorb and activate small molecules (such as CO2, N2)?
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Certainly, the electronic configuration of a metal is crucial for its ability to adsorb and activate small molecules. Metals that have empty or partially filled d orbitals are capable of forming strong bonds with these molecules, enhancing adsorption and activation processes. Additionally, the density of active sites on the metal's surface, which can be influenced by its geometric arrangement, is essential. A higher density of active sites can lead to more effective adsorption.
The surface charge of the metal also plays a role, as it can attract or repel small molecules, affecting their adsorption. Furthermore, the metal must possess sufficient energy, as determined by its work function, to facilitate electron transfer between itself and the adsorbed molecule. It is simultaneously important to ensure that the molecule is securely bound for activation without being too strongly adhered or bonded. This is why an optimal adsorption energy is necessary, to strike a balance between secure binding and ease of reaction.
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Transition Metal Catalysis.
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Database Search: Use academic databases such as PubMed, Web of Science, Scopus, Google Scholar, or specialized databases in chemistry like Reaxys or SciFinder.
Keyword Search: Use relevant keywords and phrases to narrow down your search. For Asymmetric Catalysis, you might use keywords like "asymmetric catalysis," "chiral catalysis," "enantioselective catalysis," etc. You can use Boolean operators (AND, OR, NOT) to refine your search. For example, "asymmetric catalysis" AND "organic synthesis."
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In a study on MOF catalysis, its has been mentioned that the nitrate form of the metal precursor gives good catalytic activity over other metal forms (like chloride, acetate or sulfate). Does the precursor metal forms influence the activity of a MOF (provided, similar kind of PXRD pattern obtained for same MOF prepared out of different metal form)
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Mainly because of their solubility as compared to the resulting MOFs. In addition, nitrates are poorly coordinating agents and typically do not compete with the anions the MOF is expected to form from.
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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)?
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I'm always wondering, why the people ask the question and don't look at answers.
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What is KIE's PH/PD value, and how is it used in catalysis?
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Before asking an educational question you must do dome homework. Read textbooks.
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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.
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The question is incomplete. If you can define the experimental.details of both the approaches, it should not be difficult to figure out the reason.
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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.
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Hai Dear Atiyeh Karkhaneh Jafary, I hope this will help to you
The proper potential for photocurrent analysis depends on the type of catalysis and the materials involved. In general, the potential should be chosen so that the photoexcited electrons can be injected into the conduction band of the semiconductor, but not so high that they are immediately lost to recombination. The exact potential will need to be determined experimentally for each system.
For example, in the case of photoelectrochemical water splitting, the potential should be chosen so that the photoexcited electrons can be injected into the conduction band of the semiconductor, but not so high that they are immediately lost to recombination with the holes in the valence band. The potential will also need to be high enough to oxidize water, but not so high that it causes the semiconductor to degrade.
The potential required for photocurrent analysis can also change depending on the catalyst used. For example, in the case of the oxygen evolution reaction, the potential required for a ruthenium catalyst is different from the potential required for a cobalt catalyst.
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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?
Thanks
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Edward Chandler What does the XRD pattern of the support carbon black look like? That is, with no metal loading.
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I'm trying to calculate the Tafel slope of HER and OER, I got these values and I'm not sure if is it true, any one can help me?
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There are different methods to take the data plots of the Tafel plot, but the simplest method is to use the LSV plot, to obtain the Tafel slope we first plot the Tafel plot i.e. log(j) vs overpotential, it is recommended to take the Tafel slope of obtained Tafel plot, from the linear portion obtained above onset overpotential.
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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 :)
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Organotransition Metal Chemistry: From Bonding to Catalysis by John Hartwig
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Specifically interested in purine derivative as a cation of ionic liquid.
Any relevant reading suggestions are highly appreciated. Thanks.
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Yes, there are several purine-based ionic liquids that have been described in the scientific literature.
Examples of purine-based ionic liquids include 1-butyl-3-methylimidazolium adenosine monophosphate ([BMIM][AMP]), which was first synthesized and characterized in 2011 (reference: "Synthesis and characterization of a new purine-based ionic liquid: 1-butyl-3-methylimidazolium adenosine monophosphate" by L. Zhao et al., in Tetrahedron Letters, vol. 52, p. 1130-1133, 2011).
Other examples of purine-based ionic liquids include 1-butyl-3-methylimidazolium guanosine ([BMIM][GMP]) (reference: "Synthesis and characterization of a novel purine-based ionic liquid: 1-butyl-3 -methylimidazolium guanosine" by L. Zhao et al., in Journal of Molecular Liquids, vol. 170, p. 63-66, 2012) and 1-allyl-3-methylimidazolium hypoxanthine ([AMIM][Hpx]) (reference : "Synthesis and Characterization of a New Purine-Based Ionic Liquid: 1-Allyl-3-methylimidazolium Hypoxanthine" by L. Zhao et al., in Chemical Research in Chinese Universities, vol. 32, p. 157-161, 2016) .
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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.
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To simulate the battery performance of two different configurations of electrochemical devices, you can use a variety of computational techniques, such as:
  1. Electrochemical modeling: This involves using mathematical models to describe the electrochemical behavior of the devices, such as the transport of charge, mass, and heat. The models can be based on fundamental principles of electrochemistry or derived from experimental data. There are various software packages available for electrochemical modeling, such as COMSOL, MATLAB, and PHEEC.
  2. Computational fluid dynamics (CFD): This technique is used to simulate the flow of fluids in the electrochemical devices, such as the H-type and flow-type fuel cells. CFD can provide information on the velocity, pressure, and temperature distribution within the devices, which can help to optimize their design and improve their performance. Popular CFD software packages include ANSYS Fluent, OpenFOAM, and Star-CCM+.
  3. Multiphysics simulation: This involves coupling electrochemical modeling with other physical phenomena, such as fluid dynamics, heat transfer, and mechanical deformation. Multiphysics simulation can provide a more realistic representation of the electrochemical devices and their behavior under different operating conditions.
  4. Machine learning (ML) and artificial intelligence (AI): These techniques can be used to analyze experimental data and predict the performance of the electrochemical devices. ML and AI can also be used to optimize the design of the devices and identify the key parameters that affect their performance.
The choice of simulation technique depends on the specific research question, the level of detail required, and the availability of experimental data. For example, if you want to compare the performance of H-type and flow-type fuel cells with the same catalyst, you could use electrochemical modeling to simulate the electrochemical reactions and transport of species in the devices, and compare their performance metrics, such as power output, efficiency, and durability. Alternatively, you could use CFD to simulate the fluid flow and heat transfer in the devices, and identify the optimal design parameters for each configuration.
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How do I measure activity of an enzyme if it catalyses a two-step reaction? The final product is what I want.
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For steady-state kinetics, you measure the rate of an enzyme reaction that occurs in 2 steps the same way you measure the rate of a reaction that occurs in one step: Put all the substrates in at the beginning and measure the initial rate of formation of the final product.
I worked on NAD-dependent DNA ligase, which goes by the Ping Pong mechanism mentioned by Alexander C. Anderson for a reaction with 2 substrates and 3 products, in 3 steps, as follows:
E + NAD+ <=> E-AMP + NMN
E-AMP + nDNA <=> E.AMP-nDNA <=> E + AMP + DNA
where
E is the NAD-dependent DNA ligase
NAD+ is nicotinamide adenine dinucleotide (which can be viewed as AMP-NMN)
NMN is nicotinamide mononucleotide
AMP is adenosine monophosphate
nDNA is nicked DNA
DNA is unnicked DNA
One of the intermediate stages in the reaction is a covalent adduct of AMP with the enzyme, and the other is a covalent adduct of AMP with nDNA.
Overall, the reaction is NAD+ + nDNA <=> AMP + NMN + DNA
If NAD+ is substrate A and nDNA is substrate B, the rate of product (in this case both AMP and unnicked DNA) formation (which applies to any Ping Pong mechanism with 2 substrates) is
V = (Vmax[A][B])/(KmA[B] + KmB[A] + [A][B])
The rate equation may be a bit more complicated if there is substrate inhibition caused by the second substrate binding before the first one. That will show up as a Michaelis plot of rate versus substrate concentration that rises as the substrate B concentration rises at first, then falls at higher substrate B concentrations:
V = (Vmax[A][B])/{KmA[B](1 + [B]/KiB) + KmB[A] + [A][B]}
where KiB is the substrate inhibition constant.
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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?
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The degassing time and temperature for BET surface area analysis of Ni foam samples depend on various factors such as the type of instrument, the nature of the sample, and the adsorbate used. Typically, the following degassing conditions can be used as a starting point:
  1. Heat the sample at 100°C for 1 hour under vacuum to remove any moisture or volatile impurities.
  2. Increase the temperature to 200°C and hold for 2 hours to remove any remaining moisture and adsorbed gases.
  3. Finally, increase the temperature to 300°C and hold for 3-4 hours to remove any strongly adsorbed impurities.
However, it is always best to follow the manufacturer's guidelines for the specific instrument being used.
Regarding the number of points to consider for analysis, it is recommended to analyze at least three data points for the BET analysis. These data points should be taken from a nitrogen adsorption isotherm that covers a wide range of relative pressures (typically from 0.05 to 0.30). The data points should be evenly distributed along the isotherm to ensure accurate determination of the BET surface area.
Other specific details to follow for BET surface area analysis of Ni foam samples include:
  1. The Ni foam samples should be prepared by cleaning them thoroughly using an appropriate solvent such as ethanol or acetone to remove any impurities or contaminants that may affect the analysis.
  2. The sample should be pre-dried to remove any moisture before conducting the analysis.
  3. The adsorbate used should be nitrogen gas, and the analysis should be conducted at liquid nitrogen temperature (-196°C) to ensure accurate measurements.
  4. The analysis should be conducted using an automated BET analyzer, and the results should be verified using other techniques such as mercury porosimetry or helium pycnometry.
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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?
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My field of work is mechanical processing. In addition, I inform you that I am conducting scientific-research works to increase the service life of the parts. That's why I'm interested in coating in different ways. I would like to make some changes in the construction of the devices due to some problems in the production.
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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
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Powerful dehydration is by means of azeotropic distillation. Place the dehydrated material in a round boiling flask and cover it with an organic solvent and equip it with a downdraft condenser. Bring the liquid to a boil and collect the distillate. The end of drying can be recognized when the condensate ceases to be cloudy and is clean. Due to the catalytic hydrogenation effects of Ru/carbide, fully hydrogenated Cyclohexane and the distillation temperature of 81C should not be affected. Aromatic hydrocarbons Toluene 110C and an isomeric mixture of Xylenes 1,2, 1,3 and 1,4 (para xylene) with a boiling point from 135 to 140C. Xylenes in particular achieve such a dehydrating performance that I managed to split water from the mono-hydrates of inorganic compounds. The advantage is that the removal of water takes place in an environment without the presence of air.
A cyclohexane ring carbon fully occupied by hydrogen should not react. With the more powerful Toluene and Xylene, there is a risk that it breaks the bond H2O to H-O-H and then hydrogenation and simultaneous hydroxylation due to the loss of the double bond cannot be ruled out.
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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?
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Hi,
nanoparticles tend to aggregate together due to attractive Van der Waals forces. To keep them dispersed, you must counter that attraction with a stronger force. One option is to have electrostatic repulsion, another option is to use a capping agent, i.e., something large which attaches to the particle surface and keeps the nanoparticles far away so that the short-range VdW forces stay weak. The important factors are the affinity between the capping agent, nanoparticles, and medium, the relative size of the capping agent and particles, interparticle forces, temperature, etc. You can see our publications on nanoparticle arrangement in polymer solutions - it stems from the same fundamental principle as your case.
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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.
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Thank you so much Khagesh Tanwar for your help!
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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?
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Yuxi Xu I really appreciate you clearing up the confusion.
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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
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There are several things to consider for this:
· Methyl crotonate has a fairly low boiling point (~120 C), so you should be careful when preparing your TLC not to evaporate it
· In addition to UV visualisation, you might want to use TLC stains/indicators. Iodine on silica is a good all round indicator; KMnO4 should show both the starting material and product, while using bromocresol green will show only the starting acid (to monitor its disappearance)
· Crotonates can auto-ploymerise, so you should check this as well
· Alternatively to your method, you could always use crotonyl chloride in MeOH
I hope this helps
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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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I'm not sure the size of your reactor. for the laboratory scale, the xenon lamp and mercury lamp are suitable because of their high light intensity. But in academic research, LED light sources may be a trend. I have compared conventional high-power light sources and LED in photocatalysis in my previous research, hope it works for you.
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I have used 10% H2 with 89 % Ar gas. I want to calculate H2 consumptionc (mmol g-1catalyst )
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Use GC with FID detector and Ar s a carrier gas
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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.
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Information on the reaction system under investigation and the candidate catalysts would be helpful!
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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?
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If the catalyst, I think generally as nanoparticles not bonded with nafion it is possible to full down in solution especially when gases evolved on electrode surface, erosion phenomena take place.
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Suggest some user friendly software for making graphical abstract using Smart Arts (other than Microsoft PowerPoint).
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adobe photoshop works well
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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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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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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 Rajapreethi 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