@article { ISI:000254648100007, title = {In situ synthesis of Pt nanoparticles in SBA-15 by encapsulating in modified template micelles: size restricted growth within the mesochannels}, journal = {Journal of Materials Chemistry}, volume = {18}, number = {15}, year = {2008}, month = {FEB}, pages = {1765-1770}, publisher = {ROYAL SOC CHEMISTRY}, type = {Article}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

A truly in situ and simple method is developed for nanoparticle incorporation within the mesochannels of SBA-15 involving dispersion of metal precursors in surfactant-modified polymer micelles. The diffusion of the precursor within the micellar structure is aided by interaction with the cationic head group of the surfactant leading to a unique method to facilitate the formation of highly disperse, uniform nanoparticles molded by the walls of the mesochannels. The nanoparticle incorporated mesoporous material has a highly enhanced surface area and adsorption capabilities in comparison to its parent materials without any pore blockage which makes this method ideal for the preparation of nanocatalysts.

}, issn = {0959-9428}, doi = {10.1039/b717991j}, author = {Prashar, Atul K. and Hodgkins, Robert P. and Kumar, Rajiv and Devi, R. Nandini} } @article { ISI:000274929000006, title = {In situ encapsulation of pt nanoarchitectures of varying morphologies in mesoporous compounds}, journal = {Chemistry of Materials}, volume = {22}, number = {5}, year = {2010}, month = {MAR}, pages = {1633-1639}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

Nanoparticle morphology could be engineered and fine-tuned based on a novel in situ template method Different shapes of platinum nanoparticles were obtained from very low concentrations of precursors and could be isolated exclusively inside the mesochannels of SBA-15 This was achieved by dispersing a platinum precursor in surfactant modified polymer to different extents and using these composite materials as templates for the formation of mesoporous silica [PtCl(6)](2-) interacts with the cationic headgroup of the surfactant and facilitates the isolation of precursors within the composite template leading to the formation of nanoparticles molded by the walls of the mesochannels when calcined When this [PtCl(6)](2-)-surfactant-polymer micelle composite is aged for different duration, Pt nanoparticles of various morphologies like spheroids, nano rugby balls, and nanorods are obtained

}, issn = {0897-4756}, doi = {10.1021/cm9036499}, author = {Prashar, Atul K. and Hodgkins, Robert P. and Chandran, Jima N. and Rajamohanan, P. R. and Devi, R. Nandini} } @article { ISI:000284454600041, title = {Ru(II) phenanthroline complex as catalyst for chemoselective hydrogenation of nitro-aryls in a green process}, journal = {Industrial \& Engineering Chemistry Research}, volume = {49}, number = {23}, year = {2010}, month = {DEC}, pages = {12180-12184}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

Ru(II) Phenanthroline [Ru(II)(Phen)(n) where n = 1,2,3] complexes were used as highly chemoselective catalysts for hydrogenation of nitro aryls using molecular hydrogen in an aqueous media. Water, universal solvent, was used as a reaction mixture for hydrogenation of nitro-aryls to make the process green. The chemoselectivity in hydrogenation of substituted nitrobenzene to substituted aniline was obtained as high as \>99\% at about complete conversion of substituted nitrobenzene. The parametric effects, including effect of solvent, effect of ligand, effect of metal to ligand ratio, effect of temperature and pressure, were studied in detail to obtain the best results. The Ru(Phen)(n) was characterized by FTIR, UV-vis, and XPS.

}, issn = {0888-5885}, doi = {10.1021/ie1015969}, author = {Deshmukh, Amit A. and Prashar, Atul K. and Kinage, Anil K. and Kumar, Rajiv and Meijboom, Reinout} } @article { ISI:000298910800008, title = {Growth of hydrothermally stable meso-porous silica structure interconnected around micro-porous zeolite crystals}, journal = {Materials Characterization}, volume = {62}, number = {12}, year = {2011}, month = {DEC}, pages = {1166-1172}, publisher = {ELSEVIER SCIENCE INC}, address = {360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA}, abstract = {

The growth of hydrothermally stable ordered meso-porous silica with M41S type structure interconnected around zeolite crystals was achieved from seeds normally nucleating the crystallization of micro-porous zeolite. The solid state NMR and FT-IR showed species like Si(OSi)(3)OH and Si(OSi)(2)(OH)(2) (or Q(3) and Q(2) sites, respectively) are formed during first hydrothermal treatment with surfactant and NaOH. These species and surface silanol group of zeolite crystal condense to give meso-porous silica structure interconnected around zeolite crystal during re-crystallization at lower pH. Resulting meso-micro-porous hybrid material is found to be highly active, selective and stable in the synthesis of 2-(phenylamino) ethanol from aniline and ethylene carbonate compare to parent ZSM-5 and pure MCM-41. (C) 2011 Elsevier Inc. All rights reserved.

}, keywords = {Hydrothermal stability, Interconnected meso-porous silica, Meso-micro hybrid material, Synthesis of amino alcohol}, issn = {1044-5803}, doi = {10.1016/j.matchar.2011.09.002}, author = {Kinage, Anil K. and Prashar, Atul K. and Berlier, Gloria and Chaturvedi, Rajiv K.} } @article { ISI:000295149400011, title = {In situ encapsulation of Pt nanoparticles in mesoporous silica: synthesis, characterisation and effect of particle size on CO oxidation}, journal = {Applied Catalysis A-General}, volume = {403}, number = {1-2}, year = {2011}, month = {AUG}, pages = {91-97}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Pt nanoparticles of narrow size distribution and average particle size of 4.4 nm are isolated exclusively inside SBA-12 mesoporous silica by a novel in situ method. The interaction of Pt precursor with surfactant-polymer composite micelle is followed by NMR and UV studies. The final Pt incorporated silica material is characterised by XRD, TEM and N(2) adsorption. The mesoporous nature of the silica is found to be intact after Pt incorporation without any pore blockage. CO oxidation activity of this material is compared with that of mesoporous silica incorporating different sizes of Pt viz., 1.8, 3.6 and 8 nm. Activation energies of CO oxidation for all these materials are calculated by a simple differential method based on first principles. A comparison of activation energies and single site yields reveals that these parameters are distinguishably less in catalyst containing 1.8 nm Pt nanoparticles but more or less same in catalysts containing 3.6, 4.4 and 8 nm Pt nanoparticles. (C) 2011 Elsevier B.V. All rights reserved.

}, keywords = {CO oxidation, In situ synthesis, Mesoporous silica, Pt nanoparticle}, issn = {0926-860X}, doi = {10.1016/j.apcata.2011.06.016}, author = {Prashar, Atul K. and Mayadevi, S. and Rajamohanan, P. R. and Devi, R. Nandini} } @article { ISI:000311180800010, title = {Effect of particle size on selective hydrogenation of cinnamaldehyde by Pt encapsulated in mesoporous silica}, journal = {Catalysis Communications}, volume = {28}, year = {2012}, month = {NOV}, pages = {42-46}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Pt nanoparticles of various sizes, viz. 8. 4.9, 3.6 and 1.8 nm were encapsulated in 2D hexagonal mesoporous silica by in-situ synthesis as well as post synthetic modifications so that the final catalyst composition was \<= 1 wt.\% Pt/SiO2. A kinetic analysis of the effect of particle size on selective hydrogenation of cinnamaldehyde was carried out on these catalysts. It was found that the materials, even at such low loading of Pt, were very active for the hydrogenation and selective for the desired product, cinnamyl alcohol. Among the different particle sizes, selectivity was found to be the highest on 8 nm particles. Kinetic analysis shows that the reaction follows a consecutive reaction pathway. (C) 2012 Elsevier B.V. All rights reserved.

}, keywords = {alpha, beta-Unsaturated aldehydes, Cinnamaldehyde hydrogenation, Kinetic analysis, Mesoporous silica, Pt nanoparticles, Selective hydrogenation}, issn = {1566-7367}, doi = {10.1016/j.catcom.2012.08.017}, author = {Prashar, Atul K. and Mayadevi, S. and Devi, R. Nandini} }