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Possible Growth Mechanism (possible + growth_mechanism)
Selected AbstractsOptical properties of ZnO nanotubesCRYSTAL RESEARCH AND TECHNOLOGY, Issue 6 2010Hongju Zhai Abstract Tubular ZnO nanostructures have been obtained via a hydrothermal method at low temperature (90 °C) without any catalysts or templates. The XRD measurement reveals that the tubes are single crystals with hexagonal wurtzite structure. SEM shows that the diameters of ZnO nanotubes ranged from 400 to 550 nm. The Raman and PL spectra indicate that oxygen vacancies or Zn interstitials are responsible for the green emission in the ZnO nanotubes. A possible growth mechanism on the formation of crystalline ZnO nanotubes has been presented. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Creation of calcite hollow microspheres with attached bundles of aragonite needlesCRYSTAL RESEARCH AND TECHNOLOGY, Issue 5 2008Hua Tang Abstract Novel calcite hollow microspheres attached with bundles of aragonite needles have been synthesized via a simple precipitation reaction of aqueous solutions of CaClB2B and NaB2BCOB3B in the presence of MgP2+P ions at room temperature. The experimental results revealed that an appropriate molar ratio of [MgP2+P]/[CaP2+P], pH value of the solution and aging time are crucial for the formation of the unusual hierarchical CaCOB3B superstructure. A possible growth mechanism is proposed. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Controllable Synthesis of Cu2O Microcrystals via a Complexant-Assisted Synthetic RouteEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 7 2010Wanqun Zhang Abstract A novel method using Cu(AC)2·H2O and dimethylglyoxime as reagents has been successfully developed for the controllable synthesis of Cu2O microcrystals with distinctive morphologies, including porous hollow microspheres, octahedral microcages, and microcrystals with truncated corners and edges and octahedral microcrystals. These structures can be fine-tuned by varying reaction temperature, reaction time, and concentration. The products were characterized by X-ray diffraction, field emission scanning electron microscopy, X-ray photoelectron spectra, and UV/Vis diffuse reflectance spectra. This is the first report of the preparation of the novel microcage structure of Cu2O through a simple solution-based route. By investigating the intermediate products which resemble the final crystal structures, a possible growth mechanism is proposed. Moreover, the investigations showed that the various 3D architectures of the as-made products exhibit different abilities to catalytically degrade rhodamine-B. Our work shows that octahedral Cu2O crystals with entirely {111} faces are photocatalytically more active than octahedral microcrystals with truncated corners and edges, suggesting the {111} faces of Cu2O nanostructures are catalytically more active than the {100} and {110} faces. Due to dual effect of the cavity structure and the {111} surfaces, the octahedral microcages with truncated corners and edges exhibit a higher extent of the photodecomposition reaction. As a result of very slow photocorrosion rate of the Cu2O microcrystal, it is expected that these microcrystals with different surfaces may find more applications in photocatalysis. [source] Co3O4 Nanostructures with Different Morphologies and their Field-Emission Properties,ADVANCED FUNCTIONAL MATERIALS, Issue 12 2007B. Varghese Abstract We report an efficient method to synthesize vertically aligned Co3O4 nanostructures on the surface of cobalt foils. This synthesis is accomplished by simply heating the cobalt foils in the presence of oxygen gas. The resultant morphologies of the nanostructures can be tailored to be either one-dimensional nanowires or two-dimensional nanowalls by controlling the reactivity and the diffusion rate of the oxygen species during the growth process. A possible growth mechanism governing the formation of such nanostructures is discussed. The field-emission properties of the as-synthesized nanostructures are investigated in detail. The turn-on field was determined to be 6.4 and 7.7,V,,m,1 for nanowires and nanowalls, respectively. The nanowire samples show superior field-emission characteristics with a lower turn-on field and higher current density because of their sharp tip geometry and high aspect ratio. [source] Synthesis of Novel Nickel Sulfide Submicrometer Hollow Spheres,ADVANCED MATERIALS, Issue 9 2003Y. Hu Nickel sulfide uniform hollow spheres (see scanning electron microscopy image, Figure) have been successfully synthesized by ,-irradiation of a PMMA,CS2,ethanol aqueous solution that contains NiSO4·6H2O at room temperature. Calculation shows that the diameter of the NiS hollow spheres is 500 nm and the thickness of shell is ,,20 nm. A possible growth mechanism is also presented. [source] Fabrication and characteristics of SiOx -core nanowires: Comparison study between uncoated and ZnO-coated SiOx nanowiresPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 8 2008Hyoun Woo Kim Abstract We have demonstrated an approach to the synthesis of SiOx -core nanowires, on which ZnO shell layer would be subsequently deposited. We have discussed the possible growth mechanism of SiOx nanowires, in regard to the role of Au catalyst. For a comparison study between uncoated and coated nanowires, samples were characterized by X-ray dif- fraction (XRD), transmission electron microscopy (TEM), and photoluminescence spectroscopy (PL). This method can be applied to a wide range of materials and results in various heterostructures, which may serve as potential building blocks in various nanodevices. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Single-Crystalline Scroll-Type Nanotube Arrays of Copper Hydroxide Synthesized at Room Temperature,ADVANCED MATERIALS, Issue 10 2003W. Zhang A novel nanolayer-rolled tubular structure of Cu(OH)2 has been grown in solution at ambient temperature and pressure. Significantly, the Cu(OH)2 nanotubes are phase-pure single crystallites and are arrayed uniformly on copper substrates (see Figure). The reaction conditions for the fabrication of the nanotube arrays are examined and possible growth mechanisms are discussed. [source] | |||||||||||||