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ZSM‐5 Zeolite Nanosheets with Improved Catalytic Activity Synthesized Using a New Class of Structure‐Directing Agents
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Rajkumar Kore Dr. Rajendra Srivastava Dr. Biswarup Satpati 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(36):11511-11521
A new series of multiquaternary ammonium structure‐directing agents, based on 1,4‐diazabicyclo[2.2.2]octane, was prepared. ZSM‐5 zeolites with nanosheet morphology (10 nm crystal thickness) were synthesized under hydrothermal conditions using multiquaternary ammonium surfactants as the zeolite structure‐generating agents. Both wide‐angle and small‐angle diffraction patterns were obtained using only a suitable structure‐directing agent under a specific zeolite synthesis composition. A mechanism of zeolite formation is proposed based on the results obtained from various physicochemical characterizations. ZSM‐5 materials were investigated in catalytic reactions requiring medium to strong acidity, which are important for the synthesis of a wide range of industrially important fine and specialty chemicals. The catalytic activity of ZSM‐5 materials was compared with that of the conventional ZSM‐5 and amorphous mesoporous aluminosilicate Al‐MCM‐41. The synthesis strategy of the present investigation using the new series of structure‐directing agents could be extended for the synthesis of other related zeolites or other porous materials in the future. Zeolite with a structural feature as small as the size of a unit cell (5–10 nm) with hierarchically ordered porous structure would be very promising for catalysis. 相似文献
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Priyadarshi Satpati 《Journal of organometallic chemistry》2008,693(7):1159-1165
We find sandwiched metal dimers CB5H6M-MCB5H6 (M = Si, Ge, Sn) which are minima in the potential energy surface with a characteristic M-M single bond. The NBO analysis and the M-M distances (Å) (2.3, 2.44 and 2.81 for M = Si, Ge, Sn) indicate substantial M-M bonding. Formal generation of CB5H6M-MCB5H6 has been studied theoretically. Consecutive substitution of two boron atoms in B7H−27 by M (Si, Ge, Sn) and carbon, respectively followed by dehydrogenation may lead to our desired CB5H6M-MCB5H6. We find that the slip distorted geometry is preferred for MCB5H7 and its dehydrogenated dimer CB5H6M-MCB5H6. The slip-distortion of M-M bond in CB5H6M-MCB5H6 is more than the slip distortion of M-H bond in MCB5H7. Molecular orbital analysis has been done to understand the slip distortion. Larger M-M bending (CB5H6M-MCB5H6) in comparison with M-H bending (MCB5H7) is suspected to be encouraged by stabilization of one of the M-M π bonding MO’s. Preference of M to occupy the apex of pentagonal skeleton of MCB5H7 over its icosahedral analogue MCB10H11 has been observed. 相似文献
3.
Ranjita Tandel Nagappa Teradal Ashis Satpati Seetharamappa Jaldappagari 《中国化学快报》2017,28(7):1429-1437
The present study explores an electroreduced graphene oxide-bismuth nanoparticles composite(ErGOBi) as an electrochemical sensor for the determination of an anticancer drug, gemcitabine hydrochloride(GMB). The Er-GOBi interface was prepared by drop casting of bismuth nitrate-graphene oxide suspension on a glassy carbon electrode(GCE) followed by electro-reduction in the potential range of 0.6 V to 1.7 V. SEM, FTIR, EDAX and AFM techniques were employed for the characterization of prepared materials. Cyclic voltammetric and electrochemical impedance spectroscopic methods were used to understand the charge transfer properties of stepwise modification of Er-GOBi/GCE. GMB exhibited an irreversible oxidation peak at 1.144 V on Er-GOBi/GCE in phosphate buffer of p H 3. A 100-fold enhanced oxidation peak current was observed at Er-GOBi/GCE when compared to that at bare GCE.Sensing performance of Er GO-Bi/GCE was optimized by varying peak current dependent parameters.Linear relationship between the peak current and concentration of GMB was observed in the range of 0.1–51.1 mmol/L in differential pulse voltammetric method and 2.1–61.1 mmol/L in linear sweep voltammetric method. The practical utility of the proposed sensor, Er-GOBi/GCE was demonstrated by determining GMB in pharmaceutical formulations and spiked urine samples. 相似文献
4.
Kore R Satpati B Srivastava R 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(51):14360-14365
Piperidine- and imidazole-based dicatoinic ionic liquids have been developed for the synthesis of zeolite Beta. Hierarchical Beta has a larger surface area and pore volume than conventional Beta. Beta derived from a dicationic ionic liquid exhibited remarkably higher catalytic activity than the conventional Beta. Experimental evidence and DFT calculations suggest that only a suitable conformation of such dicationic ionic liquids is able to form zeolite Beta (see scheme). 相似文献
5.
Jena BK Sahu SC Satpati B Sahu RK Behera D Mohanty S 《Chemical communications (Cambridge, England)》2011,47(13):3796-3798
A facile approach has been developed for synthesis of highly-structured, anisotropic Pd nanostructures. The dendritic Pd nanostructures show superior performance toward oxidation of formic acid and methanol for fuel cell application. 相似文献
6.
J.K. Tripathi B. Satpati A. Gupta 《Journal of magnetism and magnetic materials》2010,322(21):3464-3469
Thermal stability of thin Pt/Cr/Co multilayers and the subsequent changes in their structural, magnetic, and magneto-optical properties are reported. We observe CoCrPt ternary alloy phase formation due to annealing at temperatures about 773 K, which is accompanied by enhancement in the coercivity value. In addition, 360° domain wall superimposed on a monodomain like background has been observed in the pristine multilayer, which changes into a multidomain upon annealing at 873 K. 相似文献
7.
We consider the class \(\Sigma (p)\) of univalent meromorphic functions f on \({\mathbb D}\) having a simple pole at \(z=p\in [0,1)\) with residue 1. Let \(\Sigma _k(p)\) be the class of functions in \(\Sigma (p)\) which have k-quasiconformal extension to the extended complex plane \({\hat{\mathbb C}}\), where \(0\le k < 1\). We first give a representation formula for functions in this class and using this formula, we derive an asymptotic estimate of the Laurent coefficients for the functions in the class \(\Sigma _k(p)\). Thereafter, we give a sufficient condition for functions in \(\Sigma (p)\) to belong to the class \(\Sigma _k(p).\) Finally, we obtain a sharp distortion result for functions in \(\Sigma (p)\) and as a consequence, we obtain a distortion estimate for functions in \(\Sigma _k(p).\) 相似文献
8.
D’Souza Ozma J. Mascarenhas Ronald J. Satpati Ashis K. Detriche Simon Mekhalif Zineb Delhalle Joseph A Dhason 《Ionics》2017,23(1):201-212
Ionics - A simple and rapid method was employed for the modification of carbon paste electrode with iron nanoparticle-decorated multiwalled carbon nanotubes (MCPE/Fe-MWCNTs). The synergistic effect... 相似文献
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Ronald J Mascarenhas Ashis K Satpati Shivaraj Yellappa Bailure S Sherigara Ajjikuttira K Bopiah 《Analytical sciences》2006,22(6):871-875
A wax-impregnated carbon paste electrode with mercury oxalate as the bulk modifier is found to be suitable for the determination of heavy metal ions by differential pulse anodic stripping voltammetry. The contents of binder and modifier have been optimized, until they showed low background current and easy renewability. The bulk-modified electrode is applied for the simultaneous determination of Zn, Cd, Pb and Cu in medicinal plants and Ayurvedic tablets (Liv 52). The results obtained have been validated with HMDE and AAS and are found to be comparable. 相似文献