Raman study of CuO single crystals

Goldstein, H. F.; Kim, Dai‐Sik; Yu, Peter Y.; Bourne, L. C.; Chaminade, Jean‐Pierre; Nganga, L.

doi:10.1103/physrevb.41.7192

Cited by 146 publications

(100 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…There are three acoustic modes (Au + 2Bu), six infrared active modes (3Au + 3Bg), and three Raman active modes (Ag + 2Bg). Three Raman active optical phonons identified were comparable to that reported previously by other methods [31]. The Raman analysis of the CuO sample confirmed the three known bands having intensities of 297, 346 and 631 cm À1 , respectively, which is consistent with the previous findings [32].…”

Section: Resultssupporting

confidence: 91%

Structural and magnetic properties of CuO nanoneedles synthesized by hydrothermal method

Dar

Kim

et al. 2008

Applied Surface Science

199

View full text Add to dashboard Cite

Section: Resultssupporting

confidence: 91%

Structural and magnetic properties of CuO nanoneedles synthesized by hydrothermal method

Dar

Kim

et al. 2008

Applied Surface Science

199

View full text Add to dashboard Cite

“…The major peaks observed in the spectrum at 297 and 628 cm −1 , with a shoulder at 343 cm −1 are characteristic for crystalline tenorite CuO. [42][43][44][45] Cu 2 O is expected to show signals at 151, 280 and 650 cm −1 , 45,46 which are not observed here. The broad peak present at 1110 cm −1 is assigned as the second harmonic of the B g mode of CuO at 628 cm −1 .…”

Section: Resultsmentioning

confidence: 54%

Role of Intermetallics and Copper in the Deposition of ZrO₂Conversion Coatings on AA6014

Sarfraz

Posner

Lange

et al. 2014

J. Electrochem. Soc.

View full text Add to dashboard Cite

Zirconium oxide based conversion coatings are nickel-free alternatives to trication phosphate coatings. Here, the role of intermetallic inclusions in aluminum alloy AA6014 on the formation of Cu-rich particles inside ZrO 2 -based conversion layers with a film thickness of 25-30 nm was investigated. The role of the intermetallic inclusions on the deposition mechanism was characterized by varying the immersion time of the substrate and analyzing the coatings by electron microscopy and atomic force microscopy. Statistical analysis on the growth of the copper rich particles showed instantaneous nucleation of these particles, with a subsequent homogeneous inplane growth at constant height. A strong preferential nucleation of the Cu-rich particles on the intermetallic particles was observed, and was attributed to the cathodic nature of the intermetallics. Raman spectroscopy indicated the presence of crystalline CuO and amorphous ZrO 2 in the film. Enhanced layer formation in the vicinity of intermetallic particles was observed. Conversion coatings are widely used to protect metal surfaces from corrosion and to promote the adhesion of subsequently applied organic paints.1 While phosphate-based conversion coatings still have a large range of applications and some aspects of their formation are subject to more recent work, 2,3 current efforts focus on the replacement of conventional, μm thick phosphate and chromate containing systems by thin coatings that results in layers with an average thickness of just few tens of nm, without toxic ingredients. [4][5][6][7] One class of candidates are rare-earth based coatings. 4,6,[8][9][10] Other candidates are nanoceramic conversion coatings, typically containing zirconium or titanium oxides. Such coatings are either deposited on the surface by sol-gel chemistry, or by immersion into a fluoric acidic of Zr/Ti. Nanoceramic coatings have been shown to provide good multi-metal corrosion protection for various substrates including steel, zinc, and Al alloys, [11][12][13][14][15][16][17] and combine good corrosion performance with excellent adhesion properties. 5,[18][19][20][21][22] A lot of work has been specifically focused on investigation of zirconium or titanium based pretreatment on Al alloys. Their basic film formation mechanism is (i) fluoride etching of the oxide layer (which can be replaced by alkaline treatment), 23 (ii) onset of hydrogen evolution reaction, i.e. water reduction with a consequent increase in pH near the interface, and (iii) subsequent precipitation of oxyhydroxides as oxide precursors.24-27 Inclusion of Cu II salts (or alternatively, Fe salts) in the bath has been shown to lead to higher overall growth rate of the film on cold rolled steel compared to the solutions without Cu II . 25,28 Coatings prepared by including copper in the solution were also shown to be thicker and showed enrichment of copper within the conversion film. 25,28 Painted cold-rolled steel pretreated with a Cu-containing ZrO 2 -based coating shows low frequency impedance moduli comparabl...

show abstract

“…However, only three (Ag + 2Bg) modes are Raman active [26]. Xu et al [27] observed three Raman bands at 282, 330 and 616 cm −1 for CuO nanomaterial.…”

Section: Resultsmentioning

confidence: 99%

Physico-Chemical and Catalytic Properties of Mesoporous CuO-ZrO2 Catalysts

et al. 2016

View full text Add to dashboard Cite

Mesoporous CuO-ZrO 2 catalysts were prepared and calcined at 500˝C. The performance of the synthesized catalysts for benzylation of benzene using benzyl chloride was studied. The bare support (macroporous ZrO 2 ) offered 45% benzyl chloride conversion after reaction time of 10 h at 75˝C. Significant increase in benzyl chloride conversion (98%) was observed after CuO loading (10 wt. %) on porous ZrO 2 support. The conversion was decreased to 80% with increase of CuO loading to 20 wt. %. Different characterization techniques (XRD, Raman, diffuse reflectance UV-vis, N 2 -physisorption, H 2 -TPR, XPS and acidity measurements) were used to evaluate physico-chemical properties of CuO-ZrO 2 catalysts; the results showed that the surface and structural characteristics of the ZrO 2 phase as well as the interaction between CuO-ZrO 2 species depend strongly on the CuO content. The results also indicated that ZrO 2 support was comprised of monoclinic and tetragonal phases with macropores. An increase of the volume of monoclinic ZrO 2 phase was observed after impregnation of 10 wt. % of CuO; however, stabilization of tetragonal ZrO 2 phase was noticed after loading of 20 wt. % CuO. The presence of low-angle XRD peaks indicates that mesoscopic order is preserved in the calcined CuO-ZrO 2 catalysts. XRD reflections due to CuO phase were not observed in case of 10 wt. % CuO supported ZrO 2 sample; in contrast, the presence of crystalline CuO phase was observed in 20 wt. % CuO supported ZrO 2 sample. The mesoporous 10 wt. % CuO supported ZrO 2 catalyst showed stable catalytic activity for several reaction cycles. The observed high catalytic activity of this catalyst could be attributed to the presence of a higher number of dispersed interactive CuO (Cu 2+ -O-Zr 4+ ) species, easy reducibility, and greater degree of accessible surface Lewis acid sites.

show abstract

Raman study of CuO single crystals

Cited by 146 publications

References 6 publications

Structural and magnetic properties of CuO nanoneedles synthesized by hydrothermal method

Structural and magnetic properties of CuO nanoneedles synthesized by hydrothermal method

Role of Intermetallics and Copper in the Deposition of ZrO₂Conversion Coatings on AA6014

Physico-Chemical and Catalytic Properties of Mesoporous CuO-ZrO2 Catalysts

Contact Info

Product

Resources

About

Raman study of CuO single crystals

Cited by 146 publications

References 6 publications

Structural and magnetic properties of CuO nanoneedles synthesized by hydrothermal method

Structural and magnetic properties of CuO nanoneedles synthesized by hydrothermal method

Role of Intermetallics and Copper in the Deposition of ZrO2Conversion Coatings on AA6014

Physico-Chemical and Catalytic Properties of Mesoporous CuO-ZrO2 Catalysts

Contact Info

Product

Resources

About

Role of Intermetallics and Copper in the Deposition of ZrO₂Conversion Coatings on AA6014