01692nas a2200169   4500008004100000022001400041245010300055210006900158260011000227300001400337490000700351520098300358100002001341700002001361700001801381856012301399       2012                        eng d  a1144-054600aNovel porous silica encapsulated Au nanoreactors as peroxidase mimic for one-pot glucose detection0 aNovel porous silica encapsulated Au nanoreactors as peroxidase m  aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcDEC  a2625-26290 v363 a<p>The peroxidase family of natural enzymes facilitate H2O2 reduction by one electron transfer through aromatic substrates, if chromogenic, they can be used in the colorimetric detection of H2O2 and subsequently glucose in tandem with glucose oxidase. Au nanoparticles encapsulated within porous silica exhibited peroxidase mimetic activity and kinetic parameter evaluation indicates an excellent affinity for H2O2. It is also shown to have a detection capability for glucose in very low concentrations and could be used for glucose detection in a one-pot assay. The material is synthesised by using cation-ended thiol-stabilised ultra small gold clusters as precursors. Removal of the thiols creates micropores within the silica, making this material unique in that the active centres are protected inside the silica, yet are accessible to reactant molecules. This characteristic makes the material ideal as a detection tool where attrition resistance will be advantageous.</p>1 aSamanta, Anupam1 aDhar, Basab, B.1 aDevi, Nandini  uhttps://library.ncl.res.in/content/novel-porous-silica-encapsulated-au-nanoreactors-peroxidase-mimic-one-pot-glucose-001273nas a2200169   4500008004100000022001400041245012200055210006900177260007100246300001400317490000800331520057600339100002000915700002000935700001800955856013000973       2012                        eng d  a1932-744700aUltrasmall gold cluster arrays encapsulated in silica nanospheres: applications in fluorescence imaging and catalysis0 aUltrasmall gold cluster arrays encapsulated in silica nanosphere  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcJAN  a1748-17540 v1163 a<p>Facile synthesis of ultrasmall gold nanoclusters of size &lt;2 nm dispersible in water using a novel quaternary ammonium ligand is reported. Further, arrays of these nanoclusters are encapsulated in monodisperse silica nanospheres of size 25-30 nm. The photophysical characteristics of the clusters are found to be intact upon encapsulation, rendering the resulting composite material ideal for fluorescence imaging applications. We have further shown the utilization of these materials in catalysis as precursors for Au nanopartides encapsulated in porous silica.</p>1 aSamanta, Anupam1 aDhar, Basab, B.1 aDevi, Nandini  uhttps://library.ncl.res.in/content/ultrasmall-gold-cluster-arrays-encapsulated-silica-nanospheres-applications-fluorescence-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-001599nas a2200253   4500008004100000022001400041245014700055210006900202260007100271300001600342490000600358520064800364653002001012653001401032653002501046653001901071100002201090700002001112700002701132700002101159700002101180700001801201856012601219       2013                        eng d  a1944-824400aSelective imaging of quorum sensing receptors in bacteria using fluorescent Au nanocluster probes surface functionalized with signal molecules0 aSelective imaging of quorum sensing receptors in bacteria using   a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcDEC  a13076-130810 v53 a<p>Fluorescent ultrasmall gold clusters decorated with bacterial quorum sensing signal molecules, acyl homoserine lactone, are synthesized. These fluorescent probes are found to have emission in the near-infrared spectral region advantageous for bioimaging. Imaging studies using different. strains of bacteria with and without acyl homoserine lactone receptors with the aid of confocal microscopy have shown that the probe interacts preferentially with cells possessing these receptors. This indicates that, with appropriate surface functionalization, the Au clusters can be used for receptor specific detection with enhanced selectivity.</p>10aAu nanoclusters10aBiosensor10afluorescence imaging10aquorum sensing1 aMukherji, Ruchira1 aSamanta, Anupam1 aIllathvalappil, Rajith1 aChowdhury, Somak1 aPrabhune, Asmita1 aDevi, Nandini  uhttps://library.ncl.res.in/content/selective-imaging-quorum-sensing-receptors-bacteria-using-fluorescent-au-nanocluster-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-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-001442nas a2200157   4500008004100000245014800041210006900189260000800258300001400266490000600280520080900286100002201095700002001117700001801137856012901155       2017                        eng d00aUltra small nanoclusters to nanoparticles: fine tuning of particle size in water dispersible cation functionalized thiolate protected Pd system0 aUltra small nanoclusters to nanoparticles fine tuning of particl  cMAR  a9440-94440 v43 aMonolayer protected noble metal nanoparticles have attracted considerable attention in the past decade with potential applications in fields ranging from catalysis to biosensors [1, 2,]. We have developed a novel procedure for the synthesis of water dispersible Pd nanoparticles based on a bifunctional ligand, N,N,N-tripropyl(11-mercaptoundecyl) ammonium chloride in which thiol group binds to the metal, hydrophobic middle alkyl chain acts as capping agent and provides steric stability and on the other end the ammonia group helps in making nanoparticles hydrophilic. In this paper, we report the fine-tuning of size of water dispersible Pd nanosystems ranging from clusters to nanoparticles by adjusting the synthetic parameters and their characterization. (C) 2017 Elsevier Ltd. All rights reserved.1 aDhanraj, Prakriti1 aSamanta, Anupam1 aDevi, Nandini  uhttps://library.ncl.res.in/content/ultra-small-nanoclusters-nanoparticles-fine-tuning-particle-size-water-dispersible-cation01655nas a2200277   4500008004100000022001400041245015600055210006900211260000900280300001400289490000600303520071700309653001901026653000901045653001101054653002401065653001801089653001901107653002001126100002301146700002001169700002301189700001501212700002401227856012601251       2020                        eng d  a2574-096200aPhotocatalytic hydrogen generation and CO2 conversion using g-C3N4 decorated dendritic fibrous nanosilica: role of interfaces between silica and g-C3N40 aPhotocatalytic hydrogen generation and CO2 conversion using gC3N  cSEP   a8150-81580 v33 a<p>We have synthesized g-C3N4 decorated over dendritic fibrous nanosilica (DFNS). The generation of C-N-Si interfaces by coating each fiber of DFNS with g-C3N4 not only provided high surface area but also affected the optical and electronic properties of the composite. The catalyst synthesis reproducibility issue of g-C3N4 was resolved using a vacuum-sealed quartz tube. The extended light absorption in the visible region, enhanced lifetime of photogenerated charge carriers due to the formation of interfaces between silica and g-C3N4 (confirmed by solid-state NMR), and increased surface area result in the improved photocatalytic activity of DFNS/g-C(3)N(4)for hydrogen generation and CO2 conversion.</p>
10aCO2 conversion10aDFNS10ag-C3N410aHydrogen generation10ananocatalysts10aphotocatalysts10aSolid-state NMR1 aRawool, Sushma, A.1 aSamanta, Anupam1 aAjithkumar, T., G.1 aKar, Yusuf1 aPolshettiwar, Vivek  uhttps://library.ncl.res.in/content/photocatalytic-hydrogen-generation-and-co2-conversion-using-g-c3n4-decorated-dendritic