01485nas a2200217   4500008004100000022001400041245012600055210006900181260007300250300001200323490000800335520066500343653001001008653001801018653002201036653002301058100001801081700002401099700001801123856012601141       2012                        eng d  a1387-181100aIn situ encapsulation of ultra small ceria nanoparticles stable at high temperatures in the channels of mesoporous silica0 aIn situ encapsulation of ultra small ceria nanoparticles stable   aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcJUN  a215-2190 v1553 a<p>Ultra small ceria nanoparticles of sizes &lt;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.</p>10aceria10aEncapsulation10aMesoporous silica10aTemplate synthesis1 aGhosh, Sumona1 aJijil, Chamundi, P.1 aDevi, Nandini  uhttps://library.ncl.res.in/content/situ-encapsulation-ultra-small-ceria-nanoparticles-stable-high-temperatures-channels-001754nas a2200217   4500008004100000022001400041245011700055210006900172260007700241300001400318490000600332520094900338653002201287653001801309653001701327653001401344653001401358100002001372700001801392856012601410       2013                        eng d  a1867-388000aPd ultra-small clusters as precursors for silica-encapsulated Pd nanoreactors: highly sinter-resistant catalysts0 aPd ultrasmall clusters as precursors for silicaencapsulated Pd n  aBOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANYbWILEY-V C H VERLAG GMBHcJUL  a1911-19160 v53 a<p>Sintering and consequent deactivation in supported metal catalysts is a severe problem encountered in heterogeneous catalysis. This problem can be addressed by encapsulating active metal nanoparticles within inert oxides such as silica, provided the oxide shell is porous to enable access of reactant molecules to the nanoparticle surface to facilitate catalysis. We report the synthesis of highly sinter-resistant silica-encapsulated Pd catalysts with nanoparticle sizes stabilized at (3.4 +/- 0.6)nm at high temperatures of approximately 750 degrees C. The synthesis was achieved by utilizing thiol-protected ultra-small clusters of Pd as precursors for silica encapsulation. The ultra-small clusters were synthesized by using propyl ammonium functionalised thiols making them water-dispersible and amenable for silica encapsulation. Abundance of organics also aided in creating porosity subsequent to calcination at high temperatures.</p>10acluster compounds10aEncapsulation10ananoreactors10aPalladium10asilicates1 aSamanta, Anupam1 aDevi, Nandini  uhttps://library.ncl.res.in/content/pd-ultra-small-clusters-precursors-silica-encapsulated-pd-nanoreactors-highly-sinter-002354nas a2200241   4500008004100000022001400041245014200055210006900197260007300266300001200339490000800351520144600359653001601805653001801821653002101839653001401860653002901874100001901903700002001922700002001942700001801962856013201980       2015                        eng d  a0920-586100aEncapsulation of ultra small metal clusters in silica: evolution of the concept of nanoreactors and the case of Ag-Pd@SiO2 alloy catalyst0 aEncapsulation of ultra small metal clusters in silica evolution   aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcAUG  a114-1200 v2513 a<p>The concept of encapsulation of ultra small clusters within silica evolved as a means to address the sintering of active metal nanoparticles and subsequent deactivation observed in supported noble metal catalysts. It is hypothesised that sintering, which mainly occurs due to mobility of metal species on the support surfaces, can be minimised if the growth and movement of metal nanoparticles are constrained. First, nanoparticles are isolated inside 1D channels in 2D mesoporous compounds and the idea develops to complete encapsulation of thiol protected ultra small nanoclusters in silica spheres. Sintering is better controlled in the latter due to the confined space for growth of nanoparticles. Access of reactant molecules to the active metal surfaces also is ensured by porosity created in the silica matrix forming the basis of the concept of nanoreactors. In this paper, we elaborate on the evolution of this concept from our earlier work on highly sinter resistant silica encapsulated Au, Pd and Au-Pd alloys to the present system of Ag-Pd alloy encapsulated in silica. Silver, with the lowest Tammann temperature among noble metals, is highly prone to sintering which is adequately controlled by alloying with Pd as well as encapsulation in silica. Its enhanced activity in paranitrophenol reduction in comparison with pure metals indicates the advantageous effect of alloying. (C) 2014 Elsevier B.V. All rights reserved.</p>10aAg-Pd alloy10aEncapsulation10aSinter resistant10aSintering10aUltra small nanoclusters1 aMondal, Sourik1 aSamanta, Anupam1 aDhar, Basab, B.1 aDevi, Nandini  uhttps://library.ncl.res.in/content/encapsulation-ultra-small-metal-clusters-silica-evolution-concept-nanoreactors-and-case-ag-0