02012nas a2200277 4500008004100000022001400041245012300055210006900178260010600247300001400353490000700367520099000374653002801364653002301392653002401415653001901439653002301458100002501481700002101506700001401527700001701541700001601558700001401574700002701588856011901615 2005 eng d a0025-540800aGrowth of PbS nanopyramidal particulate films for potential applications in quantum-dot photovoltaics and nanoantennas0 aGrowth of PbS nanopyramidal particulate films for potential appl aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLANDbPERGAMON-ELSEVIER SCIENCE LTDcAUG a1353-13600 v403 a

We report a simple interfacial process called the liquid-liquid interface reaction technique (LLIRT) that leads to the formation of nanosized PbS particulate films with hitherto unreported pyramidal morphology. The resultant PbS films were characterized by transmission electron microscopy (TEM) with selected area electron diffraction (SAED), X-ray diffractometery (XRD), atomic force microscopy (AFM), near field scanning optical microscopy (NSOM) and UV-vis spectroscopy. The pyramidal morphology is speculated to originate from the preferred orientation of the 2 2 0 plane of cubic PbS. Our nanopyramidal PbS particulate films display remarkably sharp excitonic peak centered around 656 nm that accounts for a band gap of 1.8 eV suggesting, in turn, their potential application in QD photovoltaics. Interestingly, the feasibility of such nanopyramids to potentially act as nanoantennas (as revealed by the NSOM) is also suggested. (c) 2005 Elsevier Ltd. All rights reserved.

10aAtomic force microscopy10aChemical synthesis10aElectron microscopy10aNanostructures10aOptical properties1 aHawaldar, Ranjit, R.1 aMulik, Uttam, P.1 aPatil, K.1 aPasricha, R.1 aSathaye, S.1 aLewis, A.1 aAmalnerkar, Dinesh, P. uhttps://library.ncl.res.in/content/growth-pbs-nanopyramidal-particulate-films-potential-applications-quantum-dot-002891nas a2200217 4500008004100000022001400041245016300055210006900218260007100287300001400358490000800372520204400380100001402424700001802438700001502456700001302471700002102484700001402505700002302519856013102542 2009 eng d a1932-744700aComparing ultraviolet and chemical reduction techniques for enhancing photocatalytic activity of silver oxide/silver deposited nanocrystalline anatase titania0 aComparing ultraviolet and chemical reduction techniques for enha a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcAPR a6243-62550 v1133 a

Silver oxide/silver have been deposited, with varying silver concentration (0.01-10 mol %), on the surface of sol-gel derived nanocrystal line anatase titania using two different techniques, namely the ultraviolet reduction and chemical reduction (using stannous ions). The pure and silver oxide/silver-deposited nanocrystalline anatase titania have been characterized for their morphology, average nanocrystal lite size, specific surface area, phases involved, surface chemistry, band gap, and photoluminescence using various analytical techniques, such as scanning electron microscopy, transmission electron microscopy, Brunauer, Emmett, and Teller surface-area measurement, X-ray diffraction, X-ray photoelectron spectroscopy, ultraviolet-visible spectrophotometry, and spectrofluorometry, respectively. The photocatalytic activity of pure and silver oxide/silver-deposited nanocrystalline anatase titania has been measured by monitoring the degradation of methylene blue dye in an aqueous solution under ultraviolet-radiation exposure. Within the investigated Ag-concentration range, the maximum photocatalytic activity has been observed for 0.1 and 10 mol % Ag for the chemical-reduction (using stannous ions) and ultraviolet-reduction methods with the corresponding apparent first-order reaction-rate constant (k(app)) values of 0.228 and 0.151 min(-1), which are 3.5 and 2.3 times larger than that of pure nanocrystalline anatase fitania (0.065 min(-1)). The chemical-reduction method (using stannous ions), hence, appears to be more effective than the ultraviolet-reduction method for enhancing the photocatalytic activity of nanocrystalline anatase titania. Various factors such as the surface concentration of superoxide ions, oxygen-ion vacancies, and stannous ions as well as the amount of silver oxide/silver and tin oxide are observed to control the surface-adsorption of methylene blue and photoinduced electron/hole lifetime and, hence, variation in the photocatalytic activity as a function of silver concentration.

1 aPriya, R.1 aBaiju, K., V.1 aShukla, S.1 aBiju, S.1 aReddy, M., L. P.1 aPatil, K.1 aWarrier, K., G. K. uhttps://library.ncl.res.in/content/comparing-ultraviolet-and-chemical-reduction-techniques-enhancing-photocatalytic-activity-002352nas a2200265 4500008004100000022001400041245011700055210006900172260007300241300001400314490000800328520145300336653001101789653001601800653001101816653001901827653001201846653001201858100001701870700001801887700001501905700001401920700002301934856012901957 2009 eng d a0169-433200aNovel electroless process for copper coating of flyash using titania/ultraviolet-radiation/metal catalyst-system0 aNovel electroless process for copper coating of flyash using tit aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcAPR a6696-67040 v2553 a

A novel electroless process has been demonstrated in this investigation to coat the surface of flyash particles with a conducting metal such as copper. The conventional electroless process has been modified for this purpose by replacing the tin-palladium catalyst-system with the titania/ultraviolet-radiation/metal catalyst-system, where the metal is either copper or silver as demonstrated here. The mechanism of copper coating of flyash particles in an electroless bath, using the novel methods of surface-sensitization and surface-activation, has been systematically studied by monitoring changes in the surface-morphology, surface-chemistry, and surface-structure of flyash particles using the scanning electron microscope, energy dispersive analysis of X-rays, X-ray photoelectron spectroscope, and X-ray diffraction. It has been revealed that the novel electroless method involves coating the flyash particles with titania photocatalyst via sol-gel, which acts as a surface-sensitizer under the ultraviolet-radiation exposure for the subsequent surface-activation with the copper- or silver-clusters. The latter in turn acts as surface-catalyst for the subsequent Cu-coating in an electroless bath. The proposed mechanism of surface-sensitization and surface-activation of flyash particles using the novel catalyst-system has been compared with that using the conventional catalyst-system. (C) 2009 Elsevier B. V. All rights reserved.

10aCopper10aElectroless10aFlyash10aPhotocatalysis10asol-gel10atitania1 aShijitha, T.1 aBaiju, K., V.1 aShukla, S.1 aPatil, K.1 aWarrier, K., G. K. uhttps://library.ncl.res.in/content/novel-electroless-process-copper-coating-flyash-using-titaniaultraviolet-radiationmetal-0