@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: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:000302893400028, title = {In situ encapsulation of ultra small ceria nanoparticles stable at high temperatures in the channels of mesoporous silica}, journal = {Microporous and Mesoporous Materials}, volume = {155}, year = {2012}, month = {JUN}, pages = {215-219}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Ultra small ceria nanoparticles of sizes \<2 nm stable at 500 degrees C are encapsulated in the channels of mesoporous silica by employing a novel method of synthesis. The method involves modifying non-ionic polymer templates with ionic surfactants to enhance anchoring of metal ion precursors. In this way, further silica wall formation around the template ensures isolation of the nanoparticles exclusively within the channels after template removal by heat treatment. Further understanding of the interaction of the composite template system and cerium precursor is gained by cyclic voltammetric studies. (C) 2012 Elsevier Inc. All rights reserved.

}, keywords = {ceria, Encapsulation, Mesoporous silica, Template synthesis}, issn = {1387-1811}, doi = {10.1016/j.micromeso.2012.02.006}, author = {Ghosh, Sumona and Jijil, Chamundi P. and Devi, R. Nandini} } @article { ISI:000328952500024, title = {Investigations into variations in local cationic environment in layered oxide series InGaO3(ZnO)(m) (m=1-4)}, journal = {Dalton Transactions}, volume = {43}, number = {5}, year = {2014}, month = {NOV}, pages = {2120-2126}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

Layered oxides of the series InGaO3(ZnO)(m) (m = 1-4) are interesting due to their structural anisotropy. Here, we report a comprehensive study of their structural details, focusing on the local cationic environment in bulk powder samples by MASNMR and EXAFS, which is hitherto not attempted. It is found that the Ga geometry varies gradually from pure pentacoordinated to a mixture of penta and tetracoordinated with increasing amounts of tetracoordination as we move across the series, contrary to previous reports suggesting exclusively trigonal bipyramidal coordination in all the compounds. A similar observation is also made in the case of Zn and structural evolution involving the dissolution of Ga in a ZnO4 tetrahedral network in a sandwich layer can be discerned, as the insulating ZnO layer size increases.

}, issn = {1477-9226}, doi = {10.1039/c3dt52011k}, author = {Narendranath, Soumya B. and Yadav, Ashok Kumar and Ajithkumar, Thalasseril G. and Bhattacharyya, Dibyendu and Jha, Shambhu Nath and Dey, Krishna K. and Raja, Thirumalaiswamy and Devi, R. Nandini} }