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<p>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.</p>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-002326nas a2200217   4500008004100000022001400041245015700055210006900212260007300281300001000354490000700364520144400371653002601815653002801841653001301869653001501882100002001897700002601917700003301943856013201976       2008                        eng d  a0926-337300aCu-Ce mixed oxides supported on Al-pillared clay: effect of method of preparation on catalytic activity in the preferential oxidation of carbon monoxide0 aCuCe mixed oxides supported on Alpillared clay effect of method   aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcOCT  a21-290 v843 a<p>The possibility of using Al-pillared montmorillonite (Al-PILC) clay as a high-surface-area support for CuO-CeO2-based catalysts has been investigated. The preparation of the samples was done by three different methods, viz., amorphous citrate route (ACR), deposition precipitation (DP) and wet impregnation method (WIM). Samples with different CuO-CeO2 loadings (10-50 wt.%) were prepared by each of the three methods. The catalytic activity of these samples was investigated for the preferential oxidation (PROX) of carbon monoxide (CO) in excess of H-2. The samples prepared by DP and WIM methods show better activity than the samples prepared by ACR method. At low Cu content, the samples prepared by DP method have a slight edge over samples prepared by WIM method. The DP-30 sample shows a very high CO conversion of 96.1% at 423 K. A higher dispersion of CuO-CeO2 on pillared montmorillonite clay and better reducibility of copper oxide species may be responsible for the good activity of these samples even at lower reaction temperatures. A higher O-2/CO ratio increased the CO conversion but led to a reduction in oxidation selectivity. No methanation of CO or CO2 was observed at the reaction temperature. These CuO-CeO2/Al-PILC samples could be considered as comparable in performance with supported noble metal catalysts for the preferential oxidation of CO in excess hydrogen. (c) 2008 Elsevier B.V. All rights reserved.</p>10aAlumina-pillared clay10aClay-supported CuO-CeO210aCuO-CeO210aPROX of CO1 aRamaswamy, Veda1 aMalwadkar, Sachin, S.1 aChilukuri, Satyanarayana, V.  uhttps://library.ncl.res.in/content/cu-ce-mixed-oxides-supported-al-pillared-clay-effect-method-preparation-catalytic-activity-0