01401nas a2200181   4500008004100000022001400041245009200055210006900147260007100216300001400287490000800301520068900309100002600998700002601024700003001050700001801080856012101098       2012                        eng d  a1932-744700aEvidence of cationic Pt active for water-gas shift reaction: Pt-doped BaCeO3 perovskite0 aEvidence of cationic Pt active for watergas shift reaction Ptdop  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcMAY  a9526-95320 v1163 a<p>Precious metal incorporated into stable lattices like perovskites can be envisaged as an alternative catalysts to address deactivation problems. Here we report the barium cerate perovskite doped with varying amounts of Pt as catalysts for the water-gas shift reaction whereby ionic Pt is evidenced to be active. It is found that maximum CO conversion occurs above 325 degrees C and increases more than 2-fold after the first cycle. XPS analysis shows that after the first cycle, more ionic Pt species are present on the surface of the catalyst. X-ray and neutron diffraction studies also indicate the presence of oxygen vacancies that increases with increasing Pt substitution.</p>1 aRajesh, Thattarathody1 aRajarajan, Anakot, K.1 aGopinath, Chinnakonda, S.1 aDevi, Nandini  uhttps://library.ncl.res.in/content/evidence-cationic-pt-active-water-gas-shift-reaction-pt-doped-baceo3-perovskite-001425nas a2200169   4500008004100000022001400041245011600055210006900171260011000240300001400350490000600364520070100370100002001071700002601091700001801117856012001135       2014                        eng d  a2050-748800aConfined space synthesis of fully alloyed and sinter-resistant AuPd nanoparticles encapsulated in porous silica0 aConfined space synthesis of fully alloyed and sinterresistant Au  aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcJAN  a4398-44050 v23 a<p>Facile synthesis of highly sinter-resistant silica encapsulated Au-Pd alloy nanocatalysts with average particle size stabilized at similar to 4.5 nm even after calcination at 750 degrees C temperature is reported. The synthesis was achieved by utilizing thiol protected ultra small clusters of Au and Pd as precursors for silica encapsulation. The presence of intimate mixtures of the clusters within silica encapsulation ensures the formation of fully alloyed nanoparticles at high temperatures, at the same time controlling further growth and sintering. At optimum alloy compositions, these catalysts showed high catalytic activity for CO oxidation displaying low light-off temperatures.</p>1 aSamanta, Anupam1 aRajesh, Thattarathody1 aDevi, Nandini  uhttps://library.ncl.res.in/content/confined-space-synthesis-fully-alloyed-and-sinter-resistant-aupd-nanoparticles-001809nas a2200253   4500008004100000022001400041245009700055210006900152260007300221300001200294490000800306520093500314653001601249653001601265653001401281653002901295653001001324100002601334700001901360700002001379700001901399700001801418856011901436       2014                        eng d  a1381-116900aEffect of pt incorporation in LaBO3 (B = Mn, Fe, Co) perovskites on water gas shift activity0 aEffect of pt incorporation in LaBO3 B Mn Fe Co perovskites on wa  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcDEC  a506-5130 v3953 a<p>Pt incorporated perovskites LaBO3 (B = Mn, Co, Fe) were synthesised and characterised to understand the charge state of Pt in these materials. At the temperature range used in this study, Pt could be stabilised in ionic form in Co and Fe perovskites but not in LaMnO3. Consequent to incorporation of Pt in +2 and +4 oxidation states, reduction in B site ion charge state occurred, enhancing oxygen vacancies. Pt doped Co and Fe perovskites showed high activity for CO conversion under water gas shift conditions but the activity characteristics were found to be different for the two catalysts; LaCo1-xPtxO3-delta showed methanation whereas the Fe counterpart was active in water gas shift reaction. It was also observed that methanation could be decreased and water gas shift enhanced in case of Pt doped Co perovskite when compared to Pt impregnated perovskite or mixed oxides. (C) 2014 Elsevier B.V. All rights reserved.</p>10aMethanation10aPerovskites10aPt doping10aWater gas shift reaction10aXANES1 aRajesh, Thattarathody1 aUpadhyay, Anuj1 aSinha, Anil, K.1 aDeb, Sudip, K.1 aDevi, Nandini  uhttps://library.ncl.res.in/content/effect-pt-incorporation-labo3-b-mn-fe-co-perovskites-water-gas-shift-activity-001371nas a2200217   4500008004100000022001400041245017200055210006900227260005700296300001400353490000800367520054200375653001100917653001700928653001300945653001700958653000800975100002600983700001801009856012601027       2014                        eng d  a1011-372X00aPt States in BaCe0.98Pt0.02O3-delta during start up and shut down operations under different conditions: stability and activity of ionic Pt in water gas shift reaction0 aPt States in BaCe098Pt002O3delta during start up and shut down o  a233 SPRING ST, NEW YORK, NY 10013 USAbSPRINGERcDEC  a2227-22320 v1443 a<p>Stability of Pt species in doped BaCeO3 perovskites under Water gas shift reaction conditions is studied using X-ray absorption spectroscopy and in situ powder X-ray diffraction. The catalyst BaCe0.98Pt0.02O3-delta has Pt in +2 oxidation state and is found to be stable in the ionic form under reaction conditions as well as under various highly reducing shut down and start up conditions. In-situ XRD under Water Gas shift reaction conditions also reveals the Pt ions to be highly stabilized in lattice and no egress is observed.</p>10aBaCeO310aDeactivation10aplatinum10aWGS reaction10aXPS1 aRajesh, Thattarathody1 aDevi, Nandini  uhttps://library.ncl.res.in/content/pt-states-bace098pt002o3-delta-during-start-and-shut-down-operations-under-different-002066nas a2200217   4500008004100000022001400041245012400055210006900179260007300248300001200321490000800333520125700341653001801598653001601616653002901632653000801661653000801669100002601677700001801703856012701721       2014                        eng d  a1381-116900aResistance to ionic pt insertion in oxygen excess LaMnO3 perovskite lattices and its effect in water gas shift reaction0 aResistance to ionic pt insertion in oxygen excess LaMnO3 perovsk  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcDEC  a534-5420 v3953 a<p>Pt doped and impregnated LaMnO3 perovskites are synthesized at different temperatures and Pt and Mn states are compared in an attempt to get insight into extent of lattice incorporation of Pt in perovskite. Various characterization studies indicate that oxygen excess system like LaMnO3 presents substantial resistance to B site doping with Pt. This behavior is different from other oxygen deficient perovskites like LaCoO3 and LaFeO3 in which lattice incorporation stabilizes the active species against sintering. Water gas shift reaction was used as a probe reaction to understand the effect of this difference in the activity. In case of LaMnO3, failure in lattice substitution leads to sintering and deactivation at high synthesis temperatures (&gt;= 700 degrees C) in both impregnated and doped samples. In doped samples, however, a strong interaction of Pt species with a persistent amorphous phase prevents sintering at lower synthesis temperature thereby enhancing the activity when compared to impregnated sample. The study reveals a possible mechanism in which only Pt(0) species is active with perovskite playing a minimal role in this system due to the resistance to lattice incorporation. (C) 2014 Elsevier B.V. All rights reserved.</p>10aOxygen excess10aPerovskites10aWater gas shift reaction10aXPS10aXRD1 aRajesh, Thattarathody1 aDevi, Nandini  uhttps://library.ncl.res.in/content/resistance-ionic-pt-insertion-oxygen-excess-lamno3-perovskite-lattices-and-its-effect-001575nas a2200157   4500008004100000022001400041245011500055210006900170260007100239300001600310490000800326520091100334100002601245700001801271856012801289       2014                        eng d  a1932-744700aRole of oxygen vacancies in water gas shift reaction: activity study on BaCe0.98-xYxPt0.02O3-delta perovskites0 aRole of oxygen vacancies in water gas shift reaction activity st  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcSEP  a20867-208740 v1183 a<p>Oxygen vacancies are suggested to play an important role in reactions like water gas shift where the redox mechanism is crucial. Pt-doped BaCeO3 perovskite, moderately active for water gas shift reaction, is selected for further understanding the role of oxygen vacancies, since perovskite lattice can tolerate and stabilize vacancies facilitating an accurate quantification. Vacancies are created in the system by systematic doping of increasing amounts of Y. Structure and activity studies reveal that the 6% Y-substituted compound which has the most symmetric B site coordination environment exhibits the highest activity. Hence, it is not the extent of vacancies but their structural characteristics which are found to be decisive. Symmetric coordination around B ions facilitates water adsorption and dissociation by lowering the energy barriers due to the creation of an isotropic environment.</p>1 aRajesh, Thattarathody1 aDevi, Nandini  uhttps://library.ncl.res.in/content/role-oxygen-vacancies-water-gas-shift-reaction-activity-study-bace098-xyxpt002o3-delta-001768nas a2200205   4500008004100000245014400041210006900185260000800254300001600262490000700278520100500285100001901290700002601309700002001335700002101355700001501376700002901391700001801420856012401438       2017                        eng d00aUnderstanding alloy structure and composition in sinter-resistant AgPd@SiO2 encapsulated catalysts and their effect on catalytic properties0 aUnderstanding alloy structure and composition in sinterresistant  cDEC  a14652-146580 v413 aThe extent of alloying and the alloy composition, which are crucial in determining the activity and selectivity of bimetallic catalysts, were studied in porous silica encapsulated AgPd catalysts using XRD, HRTEM and HAADF-STEM. Water-dispersible ligand protected Pd ultra-small clusters and Ag nanoparticles of three different sizes were used as the precursors. The high reactivity of Pd ultra-small clusters enhanced the alloying of larger Ag nanoparticles to some extent. Encapsulation appeared to have minimised the sintering of the resultant nanoparticles. The earlier suggestions of the role of d-band positions with respect to adsorption energies holds good for the AgPd system and alloying enhances the activity. Alloy with the composition of Ag50Pd50 was found to be the most active with the reaction rate enhanced two fold compared to that in other compositions. Other factors like particle size and sinter-resistance also played important roles in enhancing the activity of these catalysts.1 aMondal, Sourik1 aRajesh, Thattarathody1 aDhar, Basab, B.1 aSnellman, Markus1 aLi, Junjie1 aDeepak, Francis, Leonard1 aDevi, Nandini  uhttps://library.ncl.res.in/content/understanding-alloy-structure-and-composition-sinter-resistant-agpdsio2-encapsulated00798nas a2200205   4500008004100000022001400041245016900055210006900224260000900293300000900302490000700311100001900318700002600337700002000363700002100383700001500404700002900419700001800448856012600466       2020                        eng d  a1144-054600aUnderstanding alloy structure and composition in sinter-resistant AgPd@SiO2 encapsulated catalysts and their effect on catalytic properties (vol 41, pg 14652, 2017)0 aUnderstanding alloy structure and composition in sinterresistant  cMAR   a46640 v441 aMondal, Sourik1 aRajesh, Thattarathody1 aDhar, Basab, B.1 aSnellman, Markus1 aLi, Junjie1 aDeepak, Francis, Leonard1 aDevi, Nandini  uhttps://library.ncl.res.in/content/understanding-alloy-structure-and-composition-sinter-resistant-agpdsio2-encapsulated-0