02203nas a2200253 4500008004100000022001400041245008000055210006900135260007300204300001000277490000800287520136700295653001201662653001001674653002401684653001101708653003401719653001201753100001901765700002001784700001801804700002001822856010701842 2005 eng d a0040-603100aCharacterization of nanocrystalline anatase titania: an in situ HTXRD study0 aCharacterization of nanocrystalline anatase titania an in situ H aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcMAR a37-410 v4273 a

Nanocrystalline titania was synthesized by the hydrolysis of titanium iso-propoxide using ultrasonication. The powder XRD patterns of the sample were recorded in static air and vacuum using a Philips X-pert Pro diffractometer equipped with a high-temperature attachment (HTK16) from room temperature (298 K) to 1173 K and were analyzed by the Rietveld refinement technique. The anatase to rutile phase transformation was observed at 1173 K for the data collected in static air. Only 3% of anatase titania transformed to rutile when the experiments were carried out at H 73 K in vacuum. The phase transformation from anatase to rutile is accompanied by a continuous increase in the crystallite size of the anatase phase from 9 nm at room temperature to 28 nm at 873 K and then to 50 nm at 1173 K in air while the process of crystallite growth was suppressed in vacuum. A linear increase in the unit cell parameters `a' and `c', and thus, an overall linear increase in the unit cell volume was observed as a function of temperature in static air as well as vacuum. The lattice and volume thermal expansion coefficients (TEC), alpha(a), alpha(c), and alpha(v) at 873 K are 8.57 x 10(-6), 8.71 x 10(-6) and 25.91 x 10(-6) K-1 in air and 18.01 x 10(-6), 14.95 x 10(-6) and 51.13 x 10(-6) K-1 in vacuum, respectively. (C) 2004 Elsevier B.V. All rights reserved.

10aAnatase10aHTXRD10aRietveld refinement10arutile10athermal expansion coefficient10atitania1 aJagtap, Neelam1 aBhagwat, Mahesh1 aAwati, Preeti1 aRamaswamy, Veda uhttps://library.ncl.res.in/content/characterization-nanocrystalline-anatase-titania-situ-htxrd-study-002006nas a2200205 4500008004100000022001400041245006900055210006900124260007300193300001000266490000700276520129000283653002201573653001701595653002701612653001901639100001901658700002001677856010301697 2006 eng d a0169-131700aOxidation of aniline over titania pillared montmorillonite clays0 aOxidation of aniline over titania pillared montmorillonite clays aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcJUL a89-980 v333 a

Titania pillared clays (Ti-PILC) have been synthesized employing conventional stirring (method I) and ultrasonic agitation (method II) techniques followed by hydrothermal treatment. The characterization results revealed the formation of Ti-PILC with significant reduction of time when ultrasonic method was used. Subsequent hydrothermal treatment on the samples has resulted in the increase in the crystallinity and the transformation of anatase TiO2 to rutile TiO2. The rutile phase is more prominent in the samples prepared by stirring method. UV-Vis studies on the samples exhibit blue shift in the absorption band due to the quantum size effect. This indicates that a major part of TiO2 in the pillared clay could be well below 10 nm in size, which is supported by XRD and the average pore size. The pillared clay catalysts have proved to be promising in aniline oxidation with H2O2, selectively forming azoxybenzene under the working conditions. The aniline conversion and the product distribution largely depended on the catalyst concentration, H2O2 to aniline mole ratio, the nature of the solvent and the oxidant. Higher conversion of aniline and greater selectivity for azoxybenzene was obtained with methanol as the solvent. (C) 2006 Elsevier B.V. All rights reserved.

10aaniline oxidation10aAzoxybenzene10ahydrothermal treatment10apillared clays1 aJagtap, Neelam1 aRamaswamy, Veda uhttps://library.ncl.res.in/content/oxidation-aniline-over-titania-pillared-montmorillonite-clays-002189nas a2200229 4500008004100000022001400041245010800055210006900163260010600232300001400338490000700352520131000359653002501669653001901694653002201713100002001735700001901755700001901774700002001793700001801813856012801831 2008 eng d a0025-540800aPhotocatalytic decomposition of methylene nanocrystalline titania prepared by different blue on methods0 aPhotocatalytic decomposition of methylene nanocrystalline titani aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLANDbPERGAMON-ELSEVIER SCIENCE LTDcMAY a1145-11520 v433 a

Nanocrystalline particles of pure anatase titania were prepared by two different methods. One is the sol-gel method at ambient temperature using ultrasonication (TiO2-SG-US) and conventional stirring method (TiO2-SG-S) and the other by surfactant assisted hydrothermal synthesis (TiO2-HT). More uniform distribution/dispersion of the nanoparticles (SEM), marginally higher surface area, better thermal stability and phase purity are some of the advantages of preparation of nanocrystalline titania by sol gel ultrasonication method and hydrothermal synthesis method. The behavior of anatase titania in photocatalytic decomposition of methylene blue in aqueous medium was studied as a function of the method of preparation and the crystallite size. The nanoparticles prepared by ultrasonication method were more effective than both, the sample prepared by conventional stirring method and commercial Degussa P-25. The higher photocatalytic activity of TiO2-SG-US is attributed to the more uniform size of the particles as compared to TiO2-SG-S samples. Both TEM and XRD data on TiO2-HT samples reveal a uniform and nanocrystalline TiO2 particles, which showed photocatalytic activity in both UV and visible region although brookite phase was also present. (C) 2007 Elsevier Ltd. All rights reserved.

10aCatalytic properties10aNanostructures10aSol-gel chemistry1 aRamaswamy, Veda1 aJagtap, Neelam1 aVijayanand, S.1 aBhange, Deu, S.1 aAwati, Preeti uhttps://library.ncl.res.in/content/photocatalytic-decomposition-methylene-nanocrystalline-titania-prepared-different-blue-002443nas a2200289 4500008004100000022001400041245012500055210006900180260007300249300001200322490000700334520143500341653001301776653002201789653001101811653003401822653002001856653000901876653002201885653000901907100001901916700002801935700001901963700002001982700002302002856012802025 2009 eng d a0926-337300aSupport modification to improve the sulphur tolerance of Ag/Al2O3 for SCR of NOx with propene under lean-burn conditions0 aSupport modification to improve the sulphur tolerance of AgAl2O3 aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcAUG a416-4250 v903 a

Ag/Al2O3 catalysts with 1 wt% SiO2 or TiO2 doping in alumina support have been prepared by wet impregnation method and tested for sulphur tolerance during the selective catalytic reduction (SCR) of NOx using propene under lean conditions, Ag/Al2O3 showed 44% NOx conversion at 623 K, which was drastically reduced to 21% when exposed to 20 ppm SO2. When Al2O3 support in Ag/Al2O3 Was doped with 1 wt% SiO2 or TiO2 the NOx conversion remained constant in presence of SO2 showing the improved sulphur tolerance of these catalysts. Subsequent water addition does not induce significant deactivation. On the contrary, a slight promotional effect on the activity of NO conversion to nitrogen is observed after Si and Ti incorporation. FTIR study showed the sulphation of silver and aluminum sites of Ag/Al2O3 catalysts resulting in the decrease in the formation of reactive intermediate species such as -NCO, which in turn decreases NOx conversion to N-2. In the case of Ag/Al2O3 doped with SiO2 or TiO2, formation of silver sulphate and aluminum sulphate was drastically reduced, which was evident in FTIR resulting in remarkable improvement in the sulphur tolerance of Ag/Al2O3 catalyst. These catalysts before and after the reaction have been characterized with various techniques (XRD, BET surface area, transmittance FTIR and pyridine adsorption) for physico-chemical properties. (C) 2009 Elsevier B.V. All rights reserved.

10aAg/Al2O310aAluminum sulphate10aDRIFTS10aSelective catalytic reduction10aSilver sulphate10aSiO210aSulphur tolerance10aTiO21 aJagtap, Neelam1 aUmbarkar, Shubhangi, B.1 aMiquel, Pierre1 aGranger, Pascal1 aDongare, Mohan, K. uhttps://library.ncl.res.in/content/support-modification-improve-sulphur-tolerance-agal2o3-scr-nox-propene-under-lean-burn-001805nas a2200265 4500008004100000022001400041245010700055210006900162260007300231300001000304490000800314520089400322653002901216653000901245653001501254653001701269653000801286100001501294700001601309700001901325700002801344700002301372700002501395856011901420 2010 eng d a1381-116900aNO reduction under diesel exhaust conditions over Au/Al2O3 prepared by deposition-precipitation method0 aNO reduction under diesel exhaust conditions over AuAl2O3 prepar aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcMAY a90-970 v3223 a

Gold supported on alumina was prepared by urea deposition-precipitation method and compared to silver supported on alumina for the selective catalytic reduction of NO by hydrocarbons under lean conditions. The catalyst showed activity in the reduction of NO and 100% selectivity towards N-2 in the temperature range 300-350 degrees C. At higher temperature the NO conversion decreased due to competitive oxidative reactions of the reductants. XPS analysis confirmed the good stability of gold nanoparticles deposited on alumina. Infrared studies showed the formation of various adsorbed species (formates, carboxylates, ad-NOx and cyanide) on the catalyst surface. Addition of H-2 to the feed containing decane enhanced the formation of these species on the catalyst surface as well as the catalytic activity for the NO conversion to N-2. (C) 2010 Elsevier B.V. All rights reserved.

10aDeposition-precipitation10aGold10aIn situ IR10aNO reduction10aXPS1 aMiguel, P.1 aGranger, P.1 aJagtap, Neelam1 aUmbarkar, Shubhangi, B.1 aDongare, Mohan, K.1 aDujardin, Christophe uhttps://library.ncl.res.in/content/no-reduction-under-diesel-exhaust-conditions-over-aual2o3-prepared-deposition-001787nas a2200241 4500008004100000022001400041245008900055210006900144260007300213300001200286490000800298520094400306653001101250653002901261653000801290653002101298100002001319700001901339700002001358700002301378700002801401856011601429 2014 eng d a0926-337300aMagnesia doped Ag/Al2O3 - sulfur tolerant catalyst for low temperature HC-SCR of NOx0 aMagnesia doped AgAl2O3 sulfur tolerant catalyst for low temperat aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcJAN a408-4150 v1443 a

A series of magnesia doped Ag/Al2O3 catalysts were prepared by modified impregnation method using boehmite as alumina precursor. The prepared catalysts were characterized and tested for the SCR of NOx using propene as reductant under lean condition. Doping of magnesia improved the low temperature catalytic activity for HC-SCR of NOx as well as sulfur tolerance. Maximum 98% NO conversion with 100% selectivity for N-2 was obtained at 350 degrees C with 7% Mg doping to Ag/Al2O3. The improvement in low temperature activity and the sulfur tolerance has been correlated to decreased acidity after addition of magnesia to alumina support. In situ FTIR study showed that the deactivation in the presence of SO2 was due to the sulfation of silver and aluminum sites in Ag/Al2O3 catalyst, however its formation was suppressed in case of magnesia doped Ag/Al2O3 improving its sulfur tolerance. (C) 2013 Elsevier B.V. All rights reserved.

10aHC-SCR10aLow temperature activity10aNOx10aSulfur tolerance1 aMore, Pavan, M.1 aJagtap, Neelam1 aKulal, Atul, B.1 aDongare, Mohan, K.1 aUmbarkar, Shubhangi, B. uhttps://library.ncl.res.in/content/magnesia-doped-agal2o3-sulfur-tolerant-catalyst-low-temperature-hc-scr-nox-0