Publications by authors named "Upendra A Joshi"

Supported Ru and Pt nanoparticles are synthesized by the method of strong electrostatic adsorption and subsequently treated under different steaming-reduction conditions to achieve a series of catalysts with controlled particle sizes, ranging from 1 to 8 nm. While in the case of oxidation-reduction conditions, only Pt yielded particles ranging from 2.5 to 8 nm in size and a loss of Ru was observed.

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A new p-type CuNb3O8 polycrystalline photoelectrode was investigated and was determined to have indirect and direct bandgap sizes of 1.26 and 1.47 eV, respectively.

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The layered semiconductor Pt-HCa(2)Nb(3)O(10) can catalyze room temperature air oxidation of methyl orange. It is also more effective than Pt-WO(3) in catalyzing reaction of methanol with air. Pt-HCa(2)Nb(3)O(10) could find wide application as a mild oxidizing catalyst.

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A new synthetic method is reported for depositing BaTiO(3) nanowire film on conducting glass. First, a TiO(2) particle thin film is prepared by spray coating, and then transformed to single crystalline BaTiO(3) nanowires grown on the conducting glass by hydrothermal treatment using TiO(2) particles as seeds of nanowire growth. The BaTiO(3) nanowires are 50-100 nm in diameter and have a film thickness of 4 µm.

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Lithium aluminate nanorods were successfully synthesized from Al2O3 nanoparticles and lithium hydroxide by a simple, large-scale hydrothermal process without any surfactant or template. The various reaction parameters were optimized to achieve the maximum yield. The as-obtained nanorods had orthorhombic beta-lithium aluminate structure with edges in the range of 40-200 nm and lengths of 1-2 mum confirmed by SEM, TEM, XRD, and NMR.

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Barium titanate nanowires synthesized with a surfactant-free hydrothermal method have been characterized by various techniques such as transmission electron microscopy (TEM), scanning electron microscopy (SEM), synchrotron X-ray diffraction, X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. The TEM and SEM analyses show the uniform cylindrical nanowires. The Rietveld refinement with synchrotron X-ray powder diffraction showed that the lattice parameters of cubic and tetragonal phases were a (= b = c) = 4.

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Beta-LiAlO2 microbricks and rectangular nanorods have been successfully synthesized from Al2O3 nanoparticles by a simple hydrothermal process without any surfactant or template, by simply changing the Li/Al molar ratio.

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