Search results for "nickel oxide"
showing 10 items of 32 documents
Mixed oxide Ti Si O prepared by non-hydrolytic Xerogel method as a diluter of nickel oxide for the oxidative dehydrogenation of ethane
2018
Abstract Mixed Ti Si O materials prepared by non-hydrolytic xerogel method have been employed as diluters for nickel oxide and used in the catalytic oxidative dehydrogenation of ethane. These catalysts have been characterized by several physicochemical techniques such as N2 adsorption, XRD, TPR, TEM, HR-TEM, and XPS. Supported nickel oxide catalysts have been reported to be efficient but only if the nature and the amount of support are controlled. In the present article it is shown that highly loaded (80 wt% NiO) nickel catalysts are more efficient when diluted on mixed Ti Si O materials with appropriate Ti/Si ratios than on pure TiO2 and SiO2 diluters. The catalytic results have been expla…
Electrochromic Devices Incorporating Cr Oxide And Ni Oxide Films:
2000
Abstract Transparent films of Cr oxide and Ni oxide were made by reactive DC magnetron sputtering in Ar+O2+H2. They displayed anodic electrochromism with charge capacities similar to that of W oxide. Cr oxide was stable in acidic environments, while Ni oxide was stable in basic environments. Electrochromic devices were made with pristine Cr oxide or Ni oxide films operating in conjunction with W oxide and a proton conducting electrolyte. Of the two oxides, Cr oxide film allowed device operation at a lower voltage span, while the device with Ni oxide film yielded a higher transmittance in the bleached state, a larger absorptance modulation, and a more neutral color.
Behavior of one-magnon frequency in antiferromagneticNicMg1−cOsolid solutions
2005
The one-magnon scattering was studied in antiferromagnetic ${\mathrm{Ni}}_{c}{\mathrm{Mg}}_{1\ensuremath{-}c}\mathrm{O}$ solid solutions. We observed unpredicted behavior of both temperature and composition dependences of one-magnon excitation energies. First, the abrupt change of the one-magnon frequency by $7--8\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}1}$ occurs between $c=0.98$ and $c=0.9$ in the limit of $T\ensuremath{\rightarrow}0\phantom{\rule{0.3em}{0ex}}\mathrm{K}$. Second, upon increasing temperature, the one-magnon energy for highly diluted nickel oxide vanishes significantly below the N\'eel temperature.
Selective oxidative dehydrogenation of ethane over SnO2-promoted NiO catalysts
2012
[EN] Ni-Sn-O mixed oxides catalysts have been investigated for the oxidative dehydrogenation of ethane. The catalysts were prepared through the evaporation of aqueous solutions of nickel nitrate and tin oxalate and finally calcined in air at 500 degrees C for 2 h. These materials have been characterized by several techniques (N-2-adsorption, X-ray diffraction, High-Resolution Electron Microscopy, temperature programmed reduction, X-Ray Photoelectron Spectroscopy, Fourier Transformed Infrared Spectroscopy of adsorbed CO and O-18/O-16 isotope exchange). The addition of just a tiny amount of tin highly increases the selectivity to ethylene (from ca. 40% to 80-90%). Thus, high selectivity to et…
Research data supporting "Antiferromagnetism and p-type conductivity of non-stoichiometric nickel oxide thin films"
2019
Raw data for the manuscript. The dataset contains the files used for the figures and tables in the Article and its Supporting Information. See the Readme file for a detailed description of the dataset.
Structure and composition of sputter-deposited nickel-tungsten oxide films
2011
Films of mixed nickel-tungsten oxide, denoted NixW1-x oxide, were prepared by reactive DC magnetron co-sputtering from metallic targets and were characterized by Rutherford backscattering spectrometry. X-ray photoelectron spectroscopy, X-ray diffractometry and Raman spectroscopy. A consistent picture of the structure and composition emerged, and at x<0.50 the films comprised a mixture of amorphous WO3 and nanosized NiWO4, at x = 0.50 the nanosized NiWO4 phase was dominating, and at x>0.50 the films contained nanosized NiO and NiWO4.
Polarisation dependent Raman study of single-crystal nickel oxide
2011
Abstract The magnetic domain structure and Raman scattering have been studied in NiO single-crystals with three different (100), (110) and (111) orientations. Twin-domain structure was observed in NiO(100) and NiO(110) single-crystals using cross-polarized optical microscopy. We found that the ratio of the two-magnon (at 1500 cm−1) to the two-phonon (2LO, at 1100 cm−1) Raman bands intensity is sensitive in a particular way to the type of the twin-domain pattern.
Defects and Reactivity at Oxide Surfaces: Experimental Aspects of the Interaction of Hydrogen, Co And Co2 with the Nio{001} Surface
1989
This paper summarizes some previous or more recent experimental results on chemical interaction, at moderate temperatures, of H, H2, CO and CO2 with the surfaces of nickel oxide, mainly the NiO {001} surface. These results are in a general agreement with theoretical predictions. Nearly perfect surfaces of maximal valency oxides cannot react with molecules. Dissociation of molecules is often required for chemisorption. Conversely, chemical reaction is usually observed either when molecules are predissociated or the surface has defects with an energy level high enough to enable both dissociation and chemisorption. On a nearly perfect, “in situ” cleaved, NiO {001} surface, partially atomized h…
Decomposition of nitrous oxide upon nickel oxide-magnesium oxide solid solutions
1966
The decomposition of N 2 O has been studied over MgO catalysts, doped with NiO and NiO + Li 2 O from 1 to 10% (atomic). For pure MgO, activity is low, but is enhanced by addition of Ni 2+ ions. The apparent activation energy is reduced from 35 kcal/mole for pure MgO, to about 18 kcal/mole. Oxygen acts as a poison, and it is chemisorbed on the catalyst. The presence of lithium greatly increases the apparent activation energy. The results are interpreted in terms of oxygen chemisorption and of its influence on the course of the reaction.
Oxidative dehydrogenation of ethane: A study over the structure and robustness of Ni–W–O catalysts
2014
[EN] The robustness of one selected Ni-W-O catalyst has been studied in the oxidative dehydrogenation of ethane. This catalyst initially deactivates for the first 10 h online decreasing 15% of its catalytic activity compared to its initial stable catalytic activity. However from 10 to 60 h online the catalytic activity keeps almost stable. On the other hand, it has been shown that the Ni-W-O catalyst cannot tolerate an oxygen-free atmosphere (C-2 and He) as nickel oxide is transformed into metallic nickel. Methane and hydrogen as well as abundant coke were formed on the surface of the catalyst in these O-free conditions. However a re-calcination in air leads to the removal of coke, the cata…