Publications (10) View all
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Article: Building crystalline Sb2S3 nanowire dandelions with multiple crystal splitting motif
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ABSTRACT: Crystalline dandelion-like antimony (III) sulfide (Sb2S3) nanowires were synthesized by a PEG-assisted solvothermal process. The orthorhombic crystal structure and dandelion-like multi-branched nanowire morphology were revealed by X-ray diffractometry (XRD) and scanning electron microscopy (SEM) respectively. High-resolution transmission electron microscopy (TEM) identified that the highly crystalline Sb2S3 nanowires grew along the [001] direction with individual wire diameter of 195±52 nm. The band gap of the Sb2S3 nanowires was measured to be ca. 1.67 eV. A combination of PEG-templated assembly and crystal splitting mechanism was likely responsible for the growth of the observed nanowire dandelion structures.Materials Letters 01/2012; 67:222-225. · 2.31 Impact Factor -
Article: Phase stabilization in nitrogen-implanted nanocrystalline cubic zirconia.
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ABSTRACT: The phase stability of nanocrystallites with metastable crystal structures under ambient conditions is usually attributed to their small grain size. It remains a challenging problem to maintain such phase integrity of these nanomaterials when their crystallite sizes become larger. Here we report an experimental-modelling approach to study the roles of nitrogen dopants in the formation and stabilization of cubic ZrO(2) nanocrystalline films. Mixed nitrogen and argon ion beam assisted deposition (IBAD) was applied to produce nitrogen-implanted cubic ZrO(2) nanocrystallites with grain sizes of 8-13 nm. Upon thermal annealing, the atomic structure of these ZrO(2) films was observed to evolve from a cubic phase, to a tetragonal phase and then a monoclinic phase. Our X-ray absorption near edge structure study on the annealed samples together with first-principle modelling revealed the significance of the interstitial nitrogen in the phase stabilization of nitrogen implanted cubic ZrO(2) crystallites via the soft mode hardening mechanism.Physical Chemistry Chemical Physics 11/2011; 13(43):19517-25. · 3.57 Impact Factor -
Article: Defect engineering in cubic cerium oxide nanostructures for catalytic oxidation.
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ABSTRACT: Traditional nanostructured design of cerium oxide catalysts typically focuses on their shape, size, and elemental composition. We report a different approach to enhance the catalytic activity of cerium oxide nanostructures through engineering high density of oxygen vacancy defects in these catalysts without dopants. The defect engineering was accomplished by a low pressure thermal activation process that exploits the nanosize effect of decreased oxygen storage capacity in nanostructured cerium oxides.Nano Letters 05/2011; 11(7):2666-71. · 13.20 Impact Factor -
Article: Techniques for Consecutive TEM and Atom Probe Tomography Analysis of Nanowires
Microscopy and Microanalysis 01/2009; 15:254-255. · 3.01 Impact Factor -
Article: Morphological Evolution of Neodymium Boride Nanostructure Growth by Chemical Vapor Deposition
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ABSTRACT: Nanoscale-driven design of electron emission materials can significantly increase their overall efficiency as cathodes for field-induced electron emission by taking advantage of the field enhancement effect. The refractory nature and low work function (1.6 eV) of neodymium hexaboride (NdB6) suggest that high aspect ratio NdB6 nanostructures are potential candidates as efficient field emission cathodes. Here we report the morphological evolution of one-dimensional neodymium boride nanostructures synthesized using palladium-nanoparticle-catalyzed chemical vapor deposition as a function of reaction temperature. Scanning electron microscopy data show that judicious choices of reaction temperatures (795−940 °C) can lead to the preferential growth of curly nanowires or high aspect ratio nanowires. Transmission electron microscopy and selected area electron diffraction reveal that the crystallinity of these nanostructures changes from amorphous, to polycrystalline, to single crystalline as the reaction temperature increases. At reaction temperatures above 900 °C, single-crystalline NdB6 nanowires with preferential [100] growth direction were successfully synthesized. Energy dispersive X-ray spectroscopic data suggest that this morphological evolution was strongly influenced by the solubility profiles of Nd and B in the Pd catalyst nanoparticles at different reaction temperatures. The implication of these results on the criteria of catalyst choices for the growth of binary metallic boride nanomaterials is also discussed.Journal of Physical Chemistry C. 01/2009; 113:0446-10451.
