Wyniki wyszukiwania - BazTech

1

In situ thermal decomposition route: Preparation and characterization of nano nickel, cobalt, and copper oxides using an aromatic amine complexes as a low-cost simple precursor

Refat Moamen S., Mohamed Soha F., Altalhi Tariq A., Bakare Safyah B., Al-Hazmi Ghaferah H.

Polish Journal of Chemical Technology

|

2021

|

Vol. 23, nr 2

47--53

EN

The main interest now is the development of metallic or inorganic-organic compounds to prepare nanoparticle materials. The use of new compounds could be beneficial and open a new method for preparing nanomaterials to control the size, shape, and size of the nanocrystals. In this article, the thermal decomposition of [M2(o-tol)2(H2O)8]Cl4 (where o-tol is ortho-tolidine compound, M = Ni2+, Co2+, Cu2+) new precursor complex was discussed in solid-state conditions. The thermal decomposition route showed that the synthesized three complexes were easily decomposed into NiO, Co3O4 and CuO nanoparticles. This decomposition was performed at low temperatures (~600°C) in atmospheric air without using any expensive and toxic solvent or complicated equipment. The obtained product was identified by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDX). FT-IR, XRD and EDX analyses revealed that the NiO nanoparticles exhibit a face-centered-cubic lattice structure with a crystallite size of 9–12 nm. The formation of a highly pure spinel-type Co3O4 phase with cubic structure showed that the Co3O4 nanoparticles have a sphere-like morphology with an average size of 8–10 nm. The XRD patterns of the CuO confirmed that the monoclinic phase with the average diameter of the spherical nanoparticles was approximately 9–15 nm.

2

Synthesis of NiO nanoparticles by sol-gel technique

Kayani Z. N., Butt M. Z., Riaz S., Naseem S.

Materials Science Poland

|

2018

|

Vol. 36, No. 4

547--552

EN

NiO nanoparticles were fabricated by sol-gel route using ammonium hydroxide and nickel nitrate as precursors. The NiO nanoparticles were calcinated at 400 °C and 1000 °C. The nanoparticles were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), vibrating sample magnetometer (VSM), thermogravimetry analysis/differential thermal analysis (TGA/DTA). The structural properties were evaluated by X-ray diffraction (XRD). XRD confirmed the formation of well-crystallized and high purity NiO phase. The XRD showed that the peaks were sharpened and the crystallite size increased as the calcination temperature increased. The average crystallite size ranged from 12 nm to 20 nm, when calcined at temperatures 400 °C and 1000 °C, respectively. Fourier transform infrared spectroscopy (FT-IR) revealed the chemical composition and confirmed the formation of NiO nanoparticles. The nanoparticles showed paramagnetic behavior.

3

Electrospinning synthesis of 3D porous NiO nanorods as anode material for lithium-ion batteries

Kong X. W., Zhang R. L., Zhong S. K., Wu L.

Materials Science Poland

|

2016

|

Vol. 34, No. 2

227--232

EN

Three-dimensional NiO nanorods were synthesized as anode material by electrospinning method. X-ray diffraction results revealed that the product sintered at 400 °C had impure metallic nickel phase which, however, became pure NiO phase as the sintering temperature rose. Nevertheless, the nanorods sintered at 400, 500 and 600 °C had similar diameters (∼200 nm).The NiO nanorod material sintered at 500 °C was chip-shaped with a diameter of 200 nm and it exhibited a porous 3D structure. The nanorod sintered at 500 °C had the optimal electrochemical performance. Its discharge specific capacity was 1127 mAh·g−1 initially and remained as high as 400 mAh·g−1 at a current density of 55 mA·g−1 after 50 cycles.

4

Effects of thermal treatment and fluoride ion doping on surface and catalytic properties of NiO–ZrO2 catalysts

Reham M. A. F., Kiwan H. A., Ahmed A. I., Mostafa M. R.

Materials Science Poland

|

2016

|

Vol. 34, No. 1

53--62

EN

ZrO2 and a series of NiO/ZrO2 hydrogels (5 to 25 wt.% NiO) were co-precipitated with the aid of NaOH–Na2 C2 O4 solution. Two fluorinated hydrogels were also prepared by wet impregnation method. The samples were calcined in the temperature range of 550 to 850 °C. The surface properties of the samples were determined using DTA, XRD and nitrogen adsorption at −196 °C. The conversion of isopropanol was tested using microcatalytic pulse technique. DTA measurements showed that the addition of nickel oxide to zirconia influences the phase transition of ZrO2. XRD revealed that the tetragonal phase was formed at T ≤ 650 °C, while a biphasic mixture was obtained at T ≥750 °C. No spinel structure was detected by both DTA and XRD techniques and only traces of cubic NiO were detected for the samples containing ≥ 15 wt.% nickel oxide and calcined at T ≤ 750 °C. Significant changes in texture, surface acidity and catalytic activity were found as a result of the effects of thermal treatment and chemical composition. Incorporation of fluoride ions greatly increased the surface acidity and consequently enhanced the dehydration activity. It has been found that dehydration activity is related to the amount of surface acidity while the dehydrogenation of this alcohol is sensitive to NiO content.

5

Spray Pyrolysis Deposition and Effect of Annealing Temperature on Optical Properties of Cu:NiO Film

Abass K. H.

International Letters of Chemistry, Physics and Astronomy

|

2015

|

Vol. 47

178--184

EN

Spray pyrolysis method that used to prepare Cu:NiO thin films onto glass substrate with various annealing temperature. Spectral transmittance of prepared thin films determined by UV-Visible spectrophotometer in the range of (380-900) nm. The transmittance decreased with increasing annealing temperature. While the absorption coefficient and extinction coefficient increased with increasing annealing temperature. Energy gap decreased from 2.9 eV before annealing to 2.78 eV after 500 ºC annealing temperature.

6

Electrical and optical properties of NiO films deposited by magnetron sputtering

Guziewicz M., Grochowski J., Borysiewicz M., Kaminska E., Domagala J. Z., Rzodkiewicz W., Witkowski B. S., Golaszewska K., Kruszka R., Ekielski M., Piotrowska A.

Optica Applicata

|

2011

|

Vol. 41, nr 2

431--440

EN

Films of transparent semiconductors are widely studied and developed because of high potential applications in electronics in last decade. Our work concerns the properties of NiO films fabricated by RF magnetron sputtering. Electrical and optical parameters of the films were characterized using Hall and transmittance measurements, respectively. P-type conductivity of as-deposited films and after annealing in oxygen or argon at the temperature range from 300 °C to 900 °C was verified. Transmittance of NiO films strongly depends on deposition temperature and oxygen amount during sputtering. Films deposited at room temperature without oxygen have transmittance near 50% in the visible range and resistivity about 65 ?cm. An increase in oxygen amount in deposition gas mixture results in higher conductivity, but transmittance decreases below 6%. Resistivity of 0.125 ?cm was attained at sputtering in oxygen. Films deposited at temperature elevated up to 500 °C are characterized by transmittance above 60% and lower conductivity. Annealing of NiO films in Ar causes resistivity to rise dramatically.

7

Analiza transmisji optycznej półprzewodnikowych warstw NiO osadzanych metodą magnetronowego rozpylania katodowego

Grochowski J., Guziewicz M., Borysiewicz M.

Elektronika : konstrukcje, technologie, zastosowania

|

2011

|

Vol. 52, nr 7

199-203

PL

Optyczne właściwości cienkich półprzewodnikowych warstw NiO wytwarzanych za pomocą reaktywnego magnetronowego rozpylania katodowego zbadano pod kątem transmisji optycznej. Określono szerokość przerwy energetycznej w zależności od warunków wzrostu warstwy. Elektryczne parametry warstw zmierzono metodą Hall'a bezpośrednio po osadzaniu oraz po procesach wygrzewania w tlenie i argonie w zakresie temperatur 200...700° C. Warstwy osadzane w temperaturze pokojowej przy zawartości tlenu w plazmie od 9% do 100% charakteryzują się transmisją poniżej 10%, przewodnictwem typu p oraz rezystywnością poniżej 0,5 Ω cm. Warstwy osadzane w podwyższonej temperaturze z zakresu 300...700° C charakteryzują się transmisją optyczną powyżej 60% oraz rezystywnością wyższą od 1 Ω cm. Wygrzewanie warstw w tlenie wywołuje zmiany transmisji i szerokości przerwy energetycznej w zależności od zastosowanej temperatury i czasu, przy czym obserwowano wzrost rezystywności po wygrzewaniu w wyższych temperaturach, zaś wygrzewanie w atmosferze argonu powoduje drastyczny spadek przewodnictwa. Warstwy NiO domieszkowano także węglem, co kilkukrotnie zmniejszało ich rezystywność. Warstwy te po dodatkowym wygrzewaniu w tlenie charakteryzują się wyższym poziomem transmisji oraz szerszą przerwą energetyczną.

EN

Optical properties of thin semiconducting NiO films deposited by reactive magnetron sputtering were examined using optical transmittance measurements. Bandgap widths of these films were calculated in dependence of deposition process' parameters. Electrical properties of films were measured after deposition and annealing processes in 0₂ and Ar at temperatures from 200...700° C by Hali method. NiO films deposited at room temperature and having oxygen amount in process plasma varying from 9% to 100% are characterized by optical transmittance below 10%, p-type conduction and resistivity lower than 0.5 Ω cm. Films deposited at temperatures elevated from 300...700° C are characterized by transmittance above 60% and resistivity higher than 1 Ω cm. Annealing in oxygen results in change of optical transmittance level and bandgap width depending on used time and temperature. Resistivity is higher after annealing at higher temperatures in oxygen while annealing in argon ambient causes conductivity to drop dramatically. Doping thin NiO films with carbon was also performed which resulted in Iower resistivity few times. After additional annealing NiO:C films in O₂ their optical transmittance level raised and bandgap width widened.