Papers by Keyword: Nanobelt

Abstract: ZrO₂ fibers and belts have been fabricated by heat-treating the hybrid fibers and belts which were prepared by electrospinning method. Fiber and belt properties, for instance, surface morphology, diameter of fibers, crystallization formation, etc. were investigated by various techniques, scanning electron microscopy (SEM), X-ray diffractometer (XRD), transmission electron microscopy (TEM), energy dispersive spectrum (EDS) included. It was found that more belts and thicker fibers appeared with increasing PVP content. Using N,N,N-trimethyl-1-dodecanaminium bromide (DTAB) can avoid formation of belts and reduce the diameter of fibers from a range of 270 to 750 nm to a range of 90 to 150 nm. It all obtained monoclinic ZrO₂ fibers and belts after heat-treating (respectively at 700, 800, 900 °C) hybrid fibers and belts. The higher temperature heat-treatment leads rougher fibers and belts.

Abstract: In this paper, the Ti-O-Compound nanobelts from commercial TiO₂ (annatase phase) were synthesized via the alkali-hydrothermal process. The as-synthesized nanobelts are sodium titanate, hydrogen titanate and anatase with general formula Na₂Ti₃O₇, H₂Ti₃O₇ and TiO₂, respectively. The nanobelts are characterized by Thermogravimetric/Differential Thermal Analysis (TG/DTA), X-ray Diffraction (XRD), Infrared Spectra (IR) and Scanning Electron Microscope (SEM) apparatuses. The characterization indicates that the nanobelts with typical widths of 50 to 200 nm, thicknesses of 20 to 50 nm, and up to a few millimeters in length. The conversion mechanisms between the layer titanate and anatase of nanobelts have been discussed in this study.

Abstract: Titania(B) nanobelt and anatase titania nanobelt could be prepared by calcining hydrogen titanate nanobelt at 450 °C and 550 °C respectively. When the hydrogen titanate was previously treated with HNO₃ for some time before calcination at 450 °C, titania(B) and anatase mixed phase titania could be obtained. The ratio of anatase phase in the product could be changed by control the time of HNO₃ treating. TEM images show that the mixed phase product was anatase nanocrystals doted on titania(B) nanobelts. The mixed phase product shows higher photocatalytic activity on the decomposition of Methylene Blue (MB) than the pure titania(B) nanobelt and anatase nanobelt.

Abstract: Zn2TiO4 nanostructures were synthesized by the thermal oxidation method. Zn with 0, 10, 20, and 30 mol% TiO2 mixed powder were blended in polyvinyl alcohol and coated on an alumina substrate to form thick films. The thick films were heated at temperature of 600, 700, and 800°C under normal atmosphere for 24 hrs. FE-SEM images showed belt-liked nanostructures with the length of 0.3-30 µm, the width of 30-1800 µm, and the thickness ranging in the order of nm. Ti was incorporated into the nanostructures with ZnO to form Zinc titanate compound, indicated by EDS. Raman spectra and XRD results suggested that phase of Zinc titanate is cubic Zn2TiO4. The oxidation temperature and TiO2 content are critical to the phase quality of the nanostructures.

Abstract: Ni nanosheet has been prepared at various temperature and time with anion surfactant by chemical reduction of the nickel ion complexes formed from complexing reagent in a pressurized vessel. Sample was characterized by the means of an X-ray diffractomer (XRD), a field emission scanning electron microscopy (FESEM), an energy dispersive X-ray spectrometer (EDS), a selected-area electron diffraction (SAED) and a high sensitive magnetometer (HSM). The use of SDBS and sodium tartrate could be a key factor for the formation and growth of Ni nanosheet.

Abstract: Zinc Oxide (ZnO) is a very useful as a solid state gas sensor material. In chemical sensing the surface and interface interactions between the analyte molecules and the sensing material is all but important that is read through the changes in electrical conductance. In that sense, nano-objects with a large surface atom/bulk atom ratio, like nanoparticles and nanowires, are potentially the best chemical sensors. The mechanism envisioned involves the adsorption (and eventually diffusion) of the analyte molecule at the surface that induces a change in the electrical resistance of the nano-object. The most convenient way to measure changes in electrical resistance in such devices is to obtain the specific material as nanowires or as connected nanoparticles. Here, we will discuss about a low-temperature wet-chemical process of synthesizing ZnO nanoparticles, nanowires and nanobelts for application as gas sensors.