scholarly journals Synthesis of Nanowires by Spray Pyrolysis

2009 ◽  
Vol 2009 ◽  
pp. 1-6 ◽  
Author(s):  
Kalyana C. Pingali ◽  
Shuguang Deng ◽  
David A. Rockstraw
Keyword(s):  
Spray Pyrolysis ◽  
Metallic Nanoparticles ◽  
Gas Flow ◽  
Nickel Chloride ◽  
X Ray ◽  
Carbon Coated ◽  
Morphological Differences ◽  
Carrier Gas Flow ◽  
Carbon Nanowires ◽  
Binary Nanoparticles

Nanowires of carbon as well as nickel-carbon (Ni-C) were synthesized by spray-pyrolysis. The carbon nanowires were synthesized using methanol as a precursor while the Ni-C nanowires were obtained by using nickel chloride methanol solution as feed. It was found that low argon carrier gas flow rates (<100 cm3/min) and suitable reaction temperatures (∼700∘C) were found to be critical for the formation of wired structures. The formation of nanowires was quite sensitive to reaction temperature. Nanowires could not form at temperatures higher than900∘C in the presence of hexane. Ruthenium chloride and nickel chloride dissolved in hexane and methanol resulted in carbon coated binary metallic nanoparticles. Morphological differences of carbon nanowires, Ni-C wires and carbon coated binary nanoparticles were characterized by scanning electron microscopy (SEM) and energy-dispersive X-ray analysis (EDS). The formation mechanism for the wired structures is proposed to explain the structural results obtained.

Synthesis and Study of Carbon Nanotubes by the Spray Pyrolysis Method Using Different Carbon Sources.

2015 ◽  
Vol 1752 ◽  
pp. 31-38
Author(s):  
Beatriz Ortega Garcia ◽  
Oxana Kharissova ◽  
Francisco Servando Aguirre-Tostado ◽  
Rasika Dias
Keyword(s):  
Carbon Nanotubes ◽  
Spray Pyrolysis ◽  
Gas Flow ◽  
Carbon Sources ◽  
Spray Pyrolysis Method ◽  
Solution Flow ◽  
Synthesis Time ◽  
Transmission Electron ◽  
Carrier Gas Flow

ABSTRACTAccording to the reports of Z.E. Horvath et al [1] and Liu Yun-quan et al [5], carbon nanotubes can be synthesized by spray pyrolysis from different carbon sources (n-pentane, n-hexane, n-heptane, cyclohexane, toluene and acrylonitrile) and several metallocene catalysts (ferrocene, cobaltocene and nickelocene). This paper describes two different existing methods for growth of carbon nanotubes and the influence of applied parameters (oven temperature, synthesis time, catalyst concentration, carrier gas flow and solution flow) on the CNT's morphology. Also, a possible influence of number of carbons in carbon sources and structures of their compounds (linear or aromatic) on properties of formed carbon nanotubes. Transmission Electron Microscopy (TEM), Infrared Spectroscopy (FTIR) and Raman spectroscopy were applied for characterization of obtained materials.

scholarly journals Agglomerate-free BaTiO3 particles by salt-assisted spray pyrolysis

2002 ◽  
Vol 17 (12) ◽  
pp. 3222-3229 ◽  
Author(s):  
Yoshifumi Itoh ◽  
I. Wuled Lenggoro ◽  
Sotiris E. Pratsinis ◽  
Kikuo Okuyama
Keyword(s):  
Spray Pyrolysis ◽  
Residence Time ◽  
Salt Concentration ◽  
Gas Flow ◽  
Thermal Treatments ◽  
X Ray Diffraction ◽  
Particle Residence Time ◽  
20 Nm ◽  
Carrier Gas Flow ◽  
Hot Zone

Optimum conditions for the synthesis of nonagglomerated BaTiO3 particles by salt-assisted spray pyrolysis (SASP) were investigated. The effect of particle residence time in the reactor and salt concentration on the crystallinity and surface morphology of BaTiO3 was examined by x-ray diffraction and scanning electron microscopy. Mixtures of a metal chloride or nitrate salt, dissolved in aqueous precursor solutions, were sprayed by an ultrasonic atomizer into a five-zone hot-wall reactor. By increasing the salt concentration or the particle residence time in the hot zone, the primary particle size was increased, and its surface texture was improved compared to BaTiO3 particles prepared by conventional spray pyrolysis. The SASP-prepared BaTiO3 crystal was transformed from cubic to tetragonal by simply increasing the salt concentration at constant temperature and residence time. Further thermal treatments such as calcination or annealing are not necessary to obtain nonagglomerated tetragonal BaTiO3 (200–500 nm) particles with a narrow size distribution. Increasing the carrier gas flow rate and decreasing the residence time in the hot zone resulted in cubic BaTiO3 particles about 20 nm in diameter.

A Microstructural Study of Iron Carbides Formed by Plasma-Enhanced Chemical Vapor Deposition (50–800 nm Thick)

1993 ◽  
Vol 313 ◽  
Author(s):  
H. Siriwardane ◽  
W.J. James ◽  
O.A. Pringle ◽  
J.W. Newkirk
Keyword(s):  
Atomic Force Microscopy ◽  
Diffraction Data ◽  
Gas Flow ◽  
Iron Carbide ◽  
Second Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Carbon Coated

Thin Mirror-like iron carbide films were prepared by introducing iron pentacarbonyl [Fe(CO)5] and hydrogen [H2] into a glow discharge. The deposition temperatures were varied from 200–500°C. The iron to carbon ratios of the resulting films were controlled by adjusting the gas flow ratios. The Microstructure and phase transformations occurring in these films were studied before and after annealing at 400°C for four hrs. Characterization techniques used included x-ray diffraction, electron diffraction, Auger spectroscopy and atomic force Microscopy.X-ray diffraction data of plasma-deposited films on glass substrates maintained at 400°C showed the presence of only Fe3C. However, the x-ray diffraction data of films on carbon coated glass, and transmission electron microscopy selected area diffraction patterns of films on carbon coated copper grids indicated the presence of a second phase, the closely related Metastable Fe7C3, as well as small amounts of Fe3O4. Atomic force microscopy of crystallites on the surface of films deposited at 400°C and annealed at 400°C for four hours revealed a periodic structure of oblate spheroids. The Measured spacings and angle, when compared to projected models of high reticular density planes, suggested the surface to have a structure corresponding to that of bulk FesC or Fe3C or Fe7C3. However the data were not of sufficient quality to unambiguously determine such.

Cathodoluminescence, X-ray excited optical luminescence, and X-ray absorption near-edge structure studies of ZnO nanostructures

2012 ◽  
Vol 90 (3) ◽  
pp. 298-305 ◽  
Author(s):  
Olga Lobacheva ◽  
Patricia L. Corcoran ◽  
Michael W. Murphy ◽  
Jun Young Peter Ko ◽  
Tsun-Kong Sham
Keyword(s):  
Gas Flow ◽  
Branching Ratio ◽  
Optical Emission ◽  
Zno Nanostructures ◽  
Edge Structure ◽  
X Ray ◽  
Synthesis Parameters ◽  
Optical Luminescence ◽  
Carrier Gas Flow ◽  
X Ray Absorption

ZnO nanostructures of various morphologies and crystallinities were fabricated by thermal evaporation from Zn powder in a tube furnace in the presence of oxygen. It was found that the morphology of ZnO nanostructures was affected by synthesis parameters, such as growth temperature, carrier gas flow, and the presence of catalyst on the surface of the substrate. Representative ZnO nanostructures were studied by X-ray excited optical luminescence (XEOL) and cathodoluminescence (CL) methods. The luminescence from these samples exhibits a morphology dependence of the branching ratio of the near band gap (NBG) emission in the UV and defect emission in the green (GE). The appearance of the optical emission also depends on the excitation method. X-ray absorption near-edge structures (XANES) at the O K-edge and Zn L-edge are also presented and their implications discussed.

PEMBUATAN NANOPARTIKEL SENG OKSIDA (ZNO)MENGGUNAKAN PROSES FLAME ASSISTED SPRAY PYROLYSIS (FASP)

EKUILIBIUM ◽  
2014 ◽  
Vol 13 (1) ◽  
Author(s):  
Agus Purwanto
Keyword(s):  
Spray Pyrolysis ◽  
Flow Rate ◽  
Zno Nanoparticles ◽  
Gas Flow ◽  
Point Of View ◽  
Carrier Gas ◽  
Flame Reactor ◽  
Mean Size ◽  
The Mean ◽  
Carrier Gas Flow

<p>Abstract: ZnO nanoparticles have been succesfully produced using Flame Assisted Spray<br />Pyrolysis (FASP) method. Burner type was a premixed flame reactor that used LPG as a fuel<br />and air as oxidizer because of an economical point of view. Zn(NO<br />3<br />)2<br />was used as a precursor<br />source for ZnO nanoparticles production. The flow rates of carrier gas during ZnO nanoparticles<br />fabrication were 5 L/menit, 7 L/menit, and 9 L/menit. To get the information about size and<br />shape of ZnO nanoparticles was characterized using Scanning Electron Microscope (SEM) and<br />X-Ray Diffractometry (XRD). The results showed that the higher carrier gas flow rate, the bigger<br />size of ZnO nanoparticles. By using the flow rate of carrier gas at 5 L/min, the mean size of ZnO<br />nanoparticles was about 80 nm. ZnO nanoparticles at carrier gas of 5 L/min were hexagonal<br />zincite crystalline structure and XRD were about 30,62 nm<br />Keywords: Flame Assisted Spray Pyrolysis, nanoparticles, ZnO, LPG, SEM, XRD</p>

Morphology-dependent luminescence from ZnO nanostructures — An X-ray excited optical luminescence study at the Zn K-edge

2009 ◽  
Vol 87 (9) ◽  
pp. 1255-1260 ◽  
Author(s):  
Olga Lobacheva ◽  
Michael W. Murphy ◽  
Jun Young Peter Ko ◽  
Tsun-Kong Sham
Keyword(s):  
Gas Flow ◽  
Thermal Evaporation ◽  
Growth Conditions ◽  
Zno Nanostructures ◽  
Edge Structure ◽  
X Ray ◽  
Si Substrates ◽  
Optical Luminescence ◽  
Carrier Gas Flow ◽  
X Ray Absorption

ZnO nanostructures have been synthesized by thermal evaporation on Si substrates. It is found that the morphologies of the nanostructures are governed by growth conditions such as temperature, carrier-gas flow rate, and the nature of the substrate (with and without a catalyst). We report X-ray excited optical luminescence from ZnO nanostructures of distinctly different morphologies in the energy and time domain using excitation photon energies across the Zn K-edge. X-ray excited optical luminescence (XEOL) and X-ray absorption near edge structure (XANES) study has clearly shown the morphology dependence of the ZnO optical properties. A correlation of luminescence with morphology, size, and crystallinity emerges.

Low temperature x-ray microanalysis of frozen-hydrated tobacco leaves

1984 ◽  
Vol 42 ◽  
pp. 284-285
Author(s):  
S. Edith Taylor ◽  
Patrick Echlin ◽  
May McKoon ◽  
Thomas L. Hayes
Keyword(s):  
Low Temperature ◽  
Lemna Minor ◽  
Root Tips ◽  
Tobacco Leaves ◽  
X Ray ◽  
Whole Cells ◽  
Carbon Coated ◽  
The Right ◽  
Beam Currents ◽  
The University

Low temperature x-ray microanalysis (LTXM) of solid biological materials has been documented for Lemna minor L. root tips. This discussion will be limited to a demonstration of LTXM for measuring relative elemental distributions of P,S,Cl and K species within whole cells of tobacco leaves.Mature Wisconsin-38 tobacco was grown in the greenhouse at the University of California, Berkeley and picked daily from the mid-stalk position (leaf #9). The tissue was excised from the right of the mid rib and rapidly frozen in liquid nitrogen slush. It was then placed into an Amray biochamber and maintained at 103K. Fracture faces of the tissue were prepared and carbon-coated in the biochamber. The prepared sample was transferred from the biochamber to the Amray 1000A SEM equipped with a cold stage to maintain low temperatures at 103K. Analyses were performed using a tungsten source with accelerating voltages of 17.5 to 20 KV and beam currents from 1-2nA.

Examination of Rabbit Fc Crystals

1968 ◽  
Vol 26 ◽  
pp. 140-141
Author(s):  
J. P. Robinson ◽  
P. G. Lenhert
Keyword(s):  
Molecular Weight ◽  
Flat Plate ◽  
Phosphate Buffer ◽  
Asymmetric Unit ◽  
X Ray Diffraction ◽  
X Ray ◽  
Neutral Ph ◽  
Small Crystals ◽  
Carbon Coated ◽  
Diffraction Patterns

Crystallographic studies of rabbit Fc using X-ray diffraction patterns were recently reported. The unit cell constants were reported to be a = 69. 2 A°, b = 73. 1 A°, c = 60. 6 A°, B = 104° 30', space group P21, monoclinic, volume of asymmetric unit V = 148, 000 A°3. The molecular weight of the fragment was determined to be 55, 000 ± 2000 which is in agreement with earlier determinations by other methods.Fc crystals were formed in water or dilute phosphate buffer at neutral pH. The resulting crystal was a flat plate as previously described. Preparations of small crystals were negatively stained by mixing the suspension with equal volumes of 2% silicotungstate at neutral pH. A drop of the mixture was placed on a carbon coated grid and allowed to stand for a few minutes. The excess liquid was removed and the grid was immediately put in the microscope.

Observation of pseudo 10-fold symmetry in the ordered iron-zinc delta phase

1992 ◽  
Vol 50 (1) ◽  
pp. 36-37
Author(s):  
L. A. Giannuzzi ◽  
A. S. Ramani ◽  
P. R. Howell ◽  
H. W. Pickering ◽  
W. R. Bitler
Keyword(s):  
Single Phase ◽  
X Ray Diffraction ◽  
Rich Region ◽  
Average Cell ◽  
X Ray ◽  
Delta Phase ◽  
Cell Dimensions ◽  
Δ Phase ◽  
Morphological Differences ◽  
Concentration Discontinuity

The δ phase is a Zn-rich intermetallic, having a composition range of ∼ 86.5 - 92.0 atomic percent Zn, and is stable up to 665°C. The stoichiometry of the δ phase has been reported as FeZn7 and FeZn10 The deviation in stoichiometry can be attributed to variations in alloy composition used by each investigator. The structure of the δ phase, as determined by powder x-ray diffraction, is hexagonal (P63mc or P63/mmc) with cell dimensions a = 1.28 nm, c = 5.76 nm, and 555±8 atoms per unit cell. Later work suggested that the layer produced by hot-dip galvanizing should be considered as two distinct phases which are characterized by their morphological differences, namely: the iron-rich region with a compact appearance (δk) and the zinc-rich region with a columnar or palisade microstructure (δp). The sub-division of the δ phase was also based on differences in diffusion behavior, and a concentration discontinuity across the δp/δk boundary. However, work utilizing Weisenberg photographs on δ single crystals reported that the variation in lattice parameters with composition was small and hence, structurally, the δk phase and the δp phase were the same and should be thought of as a single phase, δ. Bastin et al. determined the average cell dimensions to be a = 1.28 nm and c = 5.71 nm, and suggested that perhaps some kind of ordering process, which would not be observed by x-ray diffraction, may be responsible for the morphological differences within the δ phase.

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