Raman scattering in nanosized nickel oxide NiO

Миронова-Улмане, Н.; Kuzmin, Alexei; Šteins, Ints; Grabis, Jānis; Силдос, И.; Pärs, Martti

doi:10.1088/1742-6596/93/1/012039

Cited by 390 publications

(267 citation statements)

References 18 publications

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“…Regarding the surface chemistry after the tribological experiments, all studied cases showed the presence of Ni oxide (NiO) [46,47]. This is straightforwardly detected with Raman spectroscopy by observing the resonance at 550 and 1100 cm −1 .…”

Section: Structural and Chemical Analysis Of The Wear Tracksmentioning

confidence: 65%

Tribo-Mechanisms of Carbon Nanotubes: Friction and Wear Behavior of CNT-Reinforced Nickel Matrix Composites and CNT-Coated Bulk Nickel

2016

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Abstract:In this study, nickel matrix composites reinforced by carbon nanotubes (CNTs) are compared to unreinforced CNT-coated (by drop-casting) bulk nickel samples in terms of their friction and wear behavior, thus gaining significant knowledge regarding the tribological influence of CNTs and the underlying tribo-mechanism. It has been shown that the frictional behavior is mainly influenced by the CNTs present in the contact zone, as just minor differences in the coefficient of friction between the examined samples can be observed during run-in. Consequently, the known effect of a refined microstructure, thus leading to an increased hardness of the CNT reinforced samples, seems to play a minor role in friction reduction compared to the solid lubrication effect induced by the CNTs. Additionally, a continuous supply of CNTs to the tribo-contact can be considered isolated for the reinforced composites, which provides a long-term friction reduction compared to the CNT-coated sample. Finally, it can be stated that CNTs can withstand the accumulated stress retaining to some extent their structural state for the given strain. A comprehensive study performed by complementary analytical methods is employed, including Raman spectroscopy and scanning electron microscopy to understand the involved friction and wear mechanisms.

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Section: Structural and Chemical Analysis Of The Wear Tracksmentioning

confidence: 65%

Tribo-Mechanisms of Carbon Nanotubes: Friction and Wear Behavior of CNT-Reinforced Nickel Matrix Composites and CNT-Coated Bulk Nickel

2016

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“…The disappearance of 2M intensity indicates that the decrease of AFM spin correlations. M. Ulmane et al 21 have also observed a dramatic reduction in 2M intensity with decreasing NiO crystals size. This evidently confirms the increase of hysteresis behavior with decreasing NiO nanocrystals size at room temperature.…”

Section: Resultsmentioning

confidence: 84%

Size-dependent magnetic properties of branchlike nickel oxide nanocrystals

Liú

Yang

2017

AIP Advances

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Enhanced room temperature ferromagnetism in antiferromagnetic NiO nanoparticles AIP Advances 5, 087116 (2015) Branchlike nickel oxide nanocrystals with narrow size distribution are obtained by a solution growth method. The size-dependent of magnetic properties of the nickel oxides were investigated. The results of magnetic characterization indicate that the NiO nanocrystals with size below 12.8 nm show very weak ferromagnetic state at room temperature due to the uncompensated spins. Both of the average blocking temperature (T b ) and the irreversible temperature (T irr ) increase with the increase of nanoparticle sizes, while both the remnant magnetization and the coercivity at 300 K increase with the decrease of the particle sizes. Moreover, the disappearance of two-magnon (2M) band and redshift of one-phonon longitudinal (1LO) and two-phonon LO in vibrational properties due to size reduction are observed. Compared to the one with the spherical morphological, it is also found that nano-structured nickel oxides with the branchlike morphology have larger remnant magnetization and the coercivity at 5 K due to their larger surface-to-volume ratio and greater degree of broken symmetry at the surface or the higher proportion of broken bonds. © 2017 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license

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“…For single-crystal or polycrystalline NiO, vibrational bands are predicted at about 420 and 560 cm −1 due to one-phonon (1P) (TO and LO modes), at about 730 cm −1 due to two-phonon (2P) (2TO modes), at about 906 cm −1 (TO + LO), and 1090 cm −1 (2LO modes) [47,48]. Furthermore, the intensities of the (1P) band (about 560 cm −1 ) and that of (2P) band (about 1100 cm −1 ) strongly depend on NiO particle sizes and on their defectivity; the smaller the size the higher the intensity and defectivity.…”

Section: Introductionmentioning

confidence: 99%

Total Oxidation of Naphthalene with Zirconia-Supported Cobalt, Copper and Nickel Catalysts

et al. 2017

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ZrO 2 ·nH 2 O (hydrogel) impregnated with transition metals (Cu, Co, and Ni) was studied in this work as a precursor for the synthesis of CuO/ZrO 2 (CuZ), CoO x /ZrO 2 (CoZ), and NiO/ZrO 2 (NiZ) catalysts, employed in the naphthalene oxidation reaction. Fresh and catalytically used materials were characterized by different physicochemical techniques, to compare the bulk and surface behavior, with particular attention to the effect of the supported metal species' properties on the catalytic activity. Techniques such as X-ray diffraction (XRD), temperature programmed reduction (TPR), differential scanning calorimetry (DSC), Brunauer-Emmett-Teller (BET) surface area analyzer, diffuse reflectance spectroscopy (DRS UV-vis), and Raman spectroscopy, allow for establishing structural and textural aspects of the support, as well as the surface coordination and the accessibility of supported species. Results were in agreement with the CuZ > CoZ > NiZ sequence for the activity in naphthalene oxidation reaction. Electronic properties, ionic sizes, oxide phase deposition on the support surface, reducibility, metal-support interaction, and local site symmetry of metals seem to be decisive factors for the catalytic interaction with the gaseous phase.

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Raman scattering in nanosized nickel oxide NiO

Cited by 390 publications

References 18 publications

Tribo-Mechanisms of Carbon Nanotubes: Friction and Wear Behavior of CNT-Reinforced Nickel Matrix Composites and CNT-Coated Bulk Nickel

Tribo-Mechanisms of Carbon Nanotubes: Friction and Wear Behavior of CNT-Reinforced Nickel Matrix Composites and CNT-Coated Bulk Nickel

Size-dependent magnetic properties of branchlike nickel oxide nanocrystals

Total Oxidation of Naphthalene with Zirconia-Supported Cobalt, Copper and Nickel Catalysts

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