Copper (I) oxide powder generation by spray pyrolysis

1996 ◽  
Vol 11 (11) ◽  
pp. 2861-2868 ◽  
Author(s):  
D. Majumdar ◽  
T. A. Shefelbine ◽  
T. T. Kodas ◽  
H. D. Glicksman
Keyword(s):  
Spray Pyrolysis ◽  
Solid Phase ◽  
Average Crystallite Size ◽  
Copper Nitrate ◽  
Nitrogen Atmosphere ◽  
X Ray Diffraction ◽  
Oxide Powders ◽  
Phase Pure ◽  
Pure Cu ◽  
Solid Spheres

Copper oxide powders were prepared by the spray pyrolysis of copper nitrate solutions over a range of temperatures (400–1300 °C) and residence times (3–7 s). Phase-pure [by x-ray diffraction (XRD)] copper (I) oxide was obtained at 800–1300 °C in an inert (nitrogen) atmosphere. The particles varied from smooth, solid spheres at 1300 °C to irregularly shaped and hollow particles at 800 °C with dense particles of Cu2O being made only at 1000 °C or higher. The particles were polycrystalline with an average crystallite size of 42 nm at 800 °C, while at 1000–1200 °C, the particles were single crystals. Spray pyrolysis in forming gas (7% H2–N2) atmosphere at 500–700 °C gave Cu while spray pyrolysis in air yielded CuO over 800–1000 °C and a mixture of Cu2O/CuO at 1200 °C. These results show that solid, phase-pure Cu2O particles can be produced by aerosol-phase densification at temperatures below its melting point (1235 °C).

High Curie temperature perovskite BiInO3–PbTiO3 ceramics

2004 ◽  
Vol 19 (7) ◽  
pp. 2185-2193 ◽  
Author(s):  
Runrun Duan ◽  
Robert F. Speyer ◽  
Edward Alberta ◽  
Thomas R. Shrout
Keyword(s):  
Curie Temperature ◽  
Sol Gel ◽  
High Curie Temperature ◽  
Dielectric Measurements ◽  
X Ray Diffraction ◽  
Compound Formation ◽  
X Ray ◽  
Oxide Powders ◽  
Phase Pure ◽  
Pbtio3 Ceramics

The extent of BiInO3 substitution in the perovskite system xBiInO3–(1 - x)PbTiO3 and the corresponding raise in the Curie temperature were investigated using thermal analysis, dielectric measurements, x-ray diffraction, and electron microscopy. Maximum tetragonal perovskite distortion (c/a = 1.082) was obtained for x = 0.20, with a corresponding Curie temperature of 582 °C. Phase-pure tetragonal perovskite was obtained for x ⩽ 0.25. Compound formation after calcining mixed oxide powders resulted in agglomerated cube-shaped tetragonal perovskite particles, which could be fired to 94.7% of theoretical density (TD). Sol-gel fabrication resulted in nano-sized tetragonal or pseudo-cubic perovskite particles, which after two-step firing, resulted in a tetragonal perovskite microstructure at as high as (x = 0.20) 98.1% of TD.

scholarly journals Synthesis of ZnO-CuO Nanocomposite Aerogels by the Sol-Gel Route

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Rula M. Allaf ◽  
Louisa J. Hope-Weeks
Keyword(s):  
Electron Microscopy ◽  
Sol Gel ◽  
Average Crystallite Size ◽  
Copper Nitrate ◽  
Zinc Hydroxide ◽  
X Ray Diffraction ◽  
Molar Ratios ◽  
Transmission Electron ◽  
Composite Aerogels ◽  
Copper Composite

The epoxide addition sol-gel method has been utilized to synthesize porous zinc-copper composite aerogels in the zinc-to-copper molar ratios of 50 : 50 to 90 : 10. A two-step mixing approach has been employed to produce aerogels composed of nano- to micrometer sized particles. The aerogels were characterized by ultrahigh resolution scanning electron microscopy, transmission electron microscopy, and powder X-ray diffraction. The as-synthesized aerogels had a thin flake- or petal-like microstructure comprised of clustered flakes on two size scales; they were identified as being crystalline with the crystalline species identified as copper nitrate hydroxide, zinc hydroxide chloride hydrate, and zinc hydroxide nitrate hydrate. Annealing of the aerogel materials at a relatively low temperature (400°C) resulted in a complete phase transition of the material to give highly crystalline ZnO-CuO aerogels; the aerogels consisted of networked nanoparticles in the ~25–550 nm size range with an average crystallite size of ~3 nm and average crystallinity of 98%. ZnO-CuO aerogels are of particular interest due to their particular catalytic and sensing properties. This work emphasizes the versatility of this sol-gel route in synthesizing aerogels; this method offers a possible route for the fabrication of aerogels of different metal oxides and their composites.

Synthesis of W- Cu- Ag Nanopowders Produced by a Co-Precipitation Process

2011 ◽  
Vol 312-315 ◽  
pp. 312-318 ◽  
Author(s):  
Golnaz Taghavi ◽  
Hamid Reza Rezaie ◽  
Hekmat Razavizadeh
Keyword(s):  
Silver Nitrate ◽  
Copper Nitrate ◽  
Hydrogen Atmosphere ◽  
Precipitation Process ◽  
X Ray Diffraction ◽  
Composite Powders ◽  
Oxide Powders ◽  
Co Precipitation ◽  
Nanocomposite Powders ◽  
Silver Nitrate Solutions

A homogeneous precipitation process was employed to prepare nanosized W-10%wtCu-10%wtAg powders using ammonium meta tungstate, copper nitrate and silver nitrate as precursors. The initial precipitates were obtained by reacting ammonium meta tungstate, copper nitrate and silver nitrate solutions under certain PH and temperature. In order to synthesis W-Cu-Ag composite powders, the initial precipitates washed, dried, and then calcined in air in order to prepare CuWO4-x, Ag2W4O13 and WO3 oxide powders for the next step reduction. The reduction was carried out in a hydrogen atmosphere to form the final W-Cu-Ag nanocomposite powders. The powders were characterized by X-ray diffraction (XRD) technique. The morphologies of the powders were observed by scanning electron microscopy (SEM).

scholarly journals Synthesis and characterization of Cu3SbS4 thin films grown by co-sputtering metal precursors and subsequent sulfurization

2020 ◽  
Vol 1 (9) ◽  
pp. 3333-3338
Author(s):  
A Azizur Rahman ◽  
Emroj Hossian ◽  
Hetal Vaishnav ◽  
Jayesh B. Parmar ◽  
Arnab Bhattacharya ◽  
...  
Keyword(s):  
Thin Films ◽  
Synthesis And Characterization ◽  
Optical Absorption Spectra ◽  
X Ray Diffraction ◽  
Diffraction Profile ◽  
X Ray ◽  
Metal Precursors ◽  
Phase Pure ◽  
Pure Cu

X-ray diffraction profile, Raman and optical absorption spectra, and surface morphology of phase-pure Cu3SbS4 films grown at 425 °C by co-sputtering metal precursors and subsequent sulfurization.

scholarly journals A combined molecular dynamics and experimental study of two-step process enabling low-temperature formation of phase-pure α-FAPbI3

2021 ◽  
Vol 7 (17) ◽  
pp. eabe3326
Author(s):  
Paramvir Ahlawat ◽  
Alexander Hinderhofer ◽  
Essa A. Alharbi ◽  
Haizhou Lu ◽  
Amita Ummadisingu ◽  
...  
Keyword(s):  
Low Temperature ◽  
Solid Phase ◽  
Perovskite Solar Cells ◽  
X Ray Diffraction ◽  
Lead Iodide ◽  
Sequential Deposition ◽  
Phase Pure ◽  
Low Temperature Crystallization ◽  
Methylammonium Lead Iodide ◽  
Temperature Crystallization

It is well established that the lack of understanding the crystallization process in a two-step sequential deposition has a direct impact on efficiency, stability, and reproducibility of perovskite solar cells. Here, we try to understand the solid-solid phase transition occurring during the two-step sequential deposition of methylammonium lead iodide and formamidinium lead iodide. Using metadynamics, x-ray diffraction, and Raman spectroscopy, we reveal the microscopic details of this process. We find that the formation of perovskite proceeds through intermediate structures and report polymorphs found for methylammonium lead iodide and formamidinium lead iodide. From simulations, we discover a possible crystallization pathway for the highly efficient metastable α phase of formamidinium lead iodide. Guided by these simulations, we perform experiments that result in the low-temperature crystallization of phase-pure α-formamidinium lead iodide.

Combustion synthesis of ultrafine tungsten carbide powder

2008 ◽  
Vol 23 (9) ◽  
pp. 2393-2397 ◽  
Author(s):  
H.I. Won ◽  
H.H. Nersisyan ◽  
C.W. Won
Keyword(s):  
Tungsten Carbide ◽  
Combustion Synthesis ◽  
Solid Phase ◽  
Synthesis Process ◽  
Carbide Powder ◽  
X Ray Diffraction ◽  
Phase Pure ◽  
Tungsten Carbide Powder ◽  
Conversion Efficiencies ◽  
Phase Transport

The synthesis of ultrafine tungsten carbide (WC) powder has been investigated from a WO3 + Mg + C mixture via combustion technique. The values of combustion parameters were estimated over the Mg concentration range 3 to 16 mol. Fast increasing tendency of the WC/W2C phase ratio from Mg concentration has been found in the final products. Phase pure WC was prepared with more than 10 mol Mg, and a small amount of ammonium carbonate (or urea) was blended with the WO3+ C mixture. The effects of the combustion conditions on product morphology and composition were evaluated using scanning electron microscopy and x-ray diffraction analysis. The results of the investigation indicate that carbon-containing compounds significantly enhance the combustion synthesis process; leading to higher conversion efficiencies and phase pure WC formation at 1500–1550 °C. The crystalline particles of WC showed a narrow distribution in particle size, with a mean diameter around 200 nm. The results are discussed in the context of gas-phase and solid-phase transport models.

Chemical synthesis and study of structural and optoelectronic properties of CdS thin films: Effect of SILAR growth cycles

2015 ◽  
Vol 9 (3) ◽  
pp. 2461-2469
Author(s):  
S. R. Gosavi ◽  
K. B. Chaudhari
Keyword(s):  
Thin Films ◽  
Average Crystallite Size ◽  
X Ray Diffraction ◽  
Silar Method ◽  
Growth Cycles ◽  
Glass Substrates ◽  
Layer Adsorption ◽  
Cds Thin Films ◽  
Structural And Optoelectronic Properties ◽  
Deposited Film

CdS thin films were deposited on glass substrates by using successive ionic layer adsorption and reaction (SILAR) method at room temperature. The effect of SILAR growth cycles on structural, morphological, optical and electrical properties of the films has been studied.  The thickness of the deposited film is measured by employing weight difference method. The X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM) studies showed that all the films exhibit polycrystalline nature and are covered well with glass substrates. The values of average crystallite size were found to be 53 nm, 58 nm, 63 nm and 71 nm corresponding to the thin films deposited with 30, 40, 50 and 60 SILAR growth cycles respectively. From the UV–VIS spectra of the deposited thin films, it was seen that both the absorption properties and energy bandgap of the films changes with increasing number of SILAR growth cycles. A decrease of electrical resistivity has been observed with increasing SILAR growth cycle. 

Structural, Morphological, Magnetic and Self-Heating Studies of One-Step Polyol Synthesized Manganese Ferrite (MnFe2O4) Nanoparticles

2019 ◽  
Vol 19 (01) ◽  
pp. 1950003
Author(s):  
P. R. Ghutepatil ◽  
S. H. Pawar
Keyword(s):  
Room Temperature ◽  
Synthesis Method ◽  
Average Crystallite Size ◽  
Superparamagnetic Nanoparticles ◽  
Polyol Synthesis ◽  
X Ray Diffraction ◽  
Self Heating ◽  
Transmission Electron ◽  
One Step ◽  
Mnfe2o4 Nanoparticles

In this paper, uniform and superparamagnetic nanoparticles have been prepared using one-step polyol synthesis method. Structural, morphological and magnetic properties of obtained MnFe2O4 nanoparticles have been investigated by using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscope (FE-SEM), transmission electron microscopy (TEM), vibrating sample magnetometry (VSM) and thermogravimetric analysis (TGA) techniques. Structural investigation showed that the average crystallite size of obtained nanoparticles was about 10[Formula: see text]nm. Magnetic study revealed that the nanoparticles were superparamagnetic at room temperature with magnetization 67[Formula: see text]emu/g at room temperature. The self-heating characteristics of synthesized MnFe2O4 nanoparticles were studied by applying external AC magnetic field of 167.6 to 335.2[Formula: see text]Oe at a fixed frequency of 265[Formula: see text]kHz. The SAR values of MnFe2O4 nanoparticles were calculated for 2, 5, 10[Formula: see text]mg[Formula: see text]mL[Formula: see text] concentrations and it is observed that the threshold hyperthermia temperature is achieved for all concentrations.

scholarly journals Variation of the Chemical Composition of Waste Cooking Oils upon Bentonite Filtration

Resources ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 108 ◽  
Author(s):  
Alberto Mannu ◽  
Gina Vlahopoulou ◽  
Paolo Urgeghe ◽  
Monica Ferro ◽  
Alessandra Del Caro ◽  
...  
Keyword(s):  
Particle Size ◽  
Chemical Composition ◽  
Solid Phase ◽  
Volatile Fraction ◽  
X Ray Diffraction ◽  
Specific Chemical ◽  
Waste Cooking Oils ◽  
Main Components ◽  
Cooking Oils ◽  
Chemical Groups

The chemical composition and the color of samples of waste cooking oils (WCOs) were determined prior to and after filtration on two different pads of bentonite differing in particle size. The volatile fraction was monitored by headspace solid-phase microextraction (HS-SPME) coupled with gas-chromatography, while the variation of the composition of the main components was analyzed by 1H NMR. Both techniques allowed the detection of some decomposition products, such as polymers, terpenes, and derivatives of the Maillard process. The analysis of the chemical composition prior to and after bentonite treatment revealed a tendency for the clays to retain specific chemical groups (such as carboxylic acids or double bonds), independent of their particle size. A pair comparison test was conducted in order to detect the sensory differences of the intensity of aroma between the WCO treated with the two different bentonites. In addition, characterization of the bentonite by means of powder X-ray diffraction (XRD) and thermogravimetric measurements (TG) was performed.

Nanostructured TiO2-Based Composites for Light Absorption

2014 ◽  
Vol 975 ◽  
pp. 207-212
Author(s):  
Dayse I. dos Santos ◽  
Olayr Modesto Jr. ◽  
Luis Vicente A. Scalvi ◽  
Americo S. Tabata
Keyword(s):  
Metal Oxide ◽  
Light Absorption ◽  
Structural Characteristics ◽  
Sol Gel ◽  
Second Phase ◽  
X Ray Diffraction ◽  
Two Phase ◽  
X Ray ◽  
Oxide Powders

Metal oxide nanocomposites were prepared by two different routes: polyol and sol-gel. Characterization by X ray diffraction showed that the first process produces directly a two-phase material, while the sol-gel powder never showed second phase below 600°C. Light spectroscopy of the treated powders indicated similarities for the processed materials. Although the overall material compositions are about the same, different structural characteristics are found for each processing. With the exception of Ti-Zn materials, all the double metal oxide powders showed higher absorbance than either TiO2 powder.

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