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Institution

National Chemical Laboratory

FacilityPune, Maharashtra, India
About: National Chemical Laboratory is a facility organization based out in Pune, Maharashtra, India. It is known for research contribution in the topics: Catalysis & Enantioselective synthesis. The organization has 8891 authors who have published 14837 publications receiving 387600 citations.


Papers
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Journal ArticleDOI
TL;DR: In this article, the use of modified H-ZSM-5 by desilication was explored, and the increased LA conversion may be due to increase in total acidity from 43.14% to 84.31%.
Abstract: Levulinic acid (LA) is considered as a renewable platform chemical and can be used for the synthesis of variety of important fuels and chemicals. In particular, its esterification with ethanol produces ethyl levulinate (EL) would be green process, as it can be used as diesel miscible biofuel (DMB), preventing global warming by decreasing atmospheric CO 2 . This study explores the use of modified H-ZSM-5 by desilication viz.; DH-ZSM-5 and dodecatungstophosphoric acid (DTPA) loaded on DH-ZSM-5 for esterification of LA with ethanol aiming to EL. Different degree of desilication of H-ZSM-5 was performed by using aq. NaOH (0.2–1.5 M) at 338 K for 30 min and then DTPA was loaded on these desilicated H-ZSM-5 (DH-ZSM-5) support. H-ZSM-5, DH-ZSM-5 and DTPA on these DH-ZSM-5 samples were characterized by powder X-ray diffraction (XRD), N 2 adsorption–desorption, pyridine chemisorbed IR spectroscopy, Temperature Programmed Ammonia Desorption (TPAD). The increase in conversion of levulinic acid was observed from 28% to 94% with increase of DTPA loading from 0% to 15%. The increased LA conversion may be due to increase in total acidity from 43.14% to 84.31%. The use of DH-ZSM-5 as support for deposition of DTPA may be reported for the first time. The present work also extended to optimize process parameters such as DTPA loading on DH-ZSM-5, catalyst to LA ratio, LA to ethanol molar ratio, speed of agitation, particle size reaction temperature and catalyst reusability. Kinetic study based on pseudo-homogeneous (P-H) model is also presented. The experimental results follow second order kinetics.

177 citations

Journal ArticleDOI
TL;DR: In this paper, polyurethanes based on two polyols PPG (polypropylene glycol) and HTPB (hydroxy terminated polybutadiene) were synthesized using three different concentrations of the crosslinker 1,1,1-trimethylolpropane (TMP) at NCO : OH equivalent ratio 1.2 and 1.3.

177 citations

Journal ArticleDOI
TL;DR: These in-depth studies show that gold interacts predominantly with oxygen vacancies present on titania surfaces, and Pt preferentially interacts with gold for an effective electron-hole pair separation at Pt-Au interfaces and electron storage in metal particles.
Abstract: M–Au/TiO2 (M = Ag, Pd, Pt) composites were prepared through a facile one-pot photodeposition synthesis and evaluated for solar water splitting (SWS) with and without a sacrificial agent. The M–Au combination exhibits a dominant role in augmenting the H2 generation activity by forming a bi-metallic system. Degussa P25 was used as a TiO2 substrate to photodeposit Au followed by Au + M (M = Ag/Pd/Pt). The SWS activity of the M–Au/TiO2 was determined through photocatalytic H2 production in the presence of methanol as a sacrificial agent under one sun conditions with an AM1.5 filter. The highest H2 yield was observed for Pt0.5–Au1/TiO2 and was around 1.3 ± 0.07 mmol h−1 g−1, with an apparent quantum yield (AQY) of 6.4%. Pt0.5–Au1/TiO2 also demonstrated the same activity for 25 cycles of five hours each for 125 h. Critically, the same Pt0.5–Au1/TiO2 catalyst was active in overall SWS (OSWS) without any sacrificial agent, with an AQY = 0.8%. The amount of Au and/or Pt was varied to obtain the optimum composition and it was found that the Pt0.5–Au1/TiO2 composition exhibits the best activity. Detailed characterization by physico-chemical, spectral and microscopy measurements was carried out to obtain an in-depth understanding of the origin of the photocatalytic activity of Pt0.5–Au1/TiO2. These in-depth studies show that gold interacts predominantly with oxygen vacancies present on titania surfaces, and Pt preferentially interacts with gold for an effective electron–hole pair separation at Pt–Au interfaces and electron storage in metal particles. The Pt in Pt0.5–Au1/TiO2 is electronically and catalytically different from the Pt in Pt/TiO2 and it is predicted that the former suppresses the oxygen reduction reaction.

176 citations

Journal ArticleDOI
TL;DR: In this paper, a simple and convenient method for the synthesis of gold, silver and their alloy nanoparticles in a foam matrix using the protein bovine serum albumin (BSA) is reported.
Abstract: A simple and convenient method for the synthesis of gold, silver and their alloy nanoparticles in a foam matrix using the protein bovine serum albumin (BSA) is reported. BSA is an excellent foaming agent and,by virtue of its zwitterionic character at the protein isoelectric point, may be used to bind to either cationic silver (Ag+) or anionic gold (AuCl4−) ions in the foam. The metal ions in the foam are thereafter reduced in situ to yield silver and gold nanoparticles. The versatility of an amphoteric foaming agent is further demonstrated by the simultaneous binding of Ag+ and AuCl4− ions with zwitterionic BSA leading to the possibility of obtaining Au–Ag alloy nanoparticles in the foam. The BSA molecules coat and stabilize the nanoparticles thus prepared eliminating the necessity of employing an additional stabilizing agent in the experimental recipe.

176 citations

Journal ArticleDOI
TL;DR: In this paper, the bulk crystal of black phosphorus was exfoliated by liquid exfoliation method for a duration of 8h using N-Methyl-2-Pyrrolidone as the solvent.

176 citations


Authors

Showing all 8913 results

NameH-indexPapersCitations
Ashok Kumar1515654164086
Rajesh Kumar1494439140830
Tak W. Mak14880794871
John T. O'Brien12181963242
Clive Ballard11773661663
Yoshinori Tokura11785870258
John S. Mattick11636764315
Michael Dean10741963335
Ian G. McKeith10746851954
David J. Burn10044639120
Anil Kumar99212464825
Vikas Kumar8985939185
Detlef W. Bahnemann8851748826
Gautam R. Desiraju8845845301
Praveen Kumar88133935718
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
20236
202238
2021482
2020454
2019471
2018498