• Title, Summary, Keyword: Copper Oxide (CuO)

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Synthesis of Graphene Oxide Based CuOx Nanocomposites and Application for C-N Cross Coupling Reaction

  • Choi, Jong Hoon;Park, Joon B.
    • Proceedings of the Korean Vacuum Society Conference
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    • pp.176.1-176.1
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    • 2014
  • Graphene has attracted an increasing attention due to its extraordinary electronic, mechanical, and thermal properties. Especially, the two dimensional (2D) sheet of graphene with an extremely high surface to volume ratio has a great potential in the preparation of multifunctional nanomaterials, as 2D supports to host metal nanoparticles (NPs). Copper oxide is widely used in various areas as antifouling paint, p-type semiconductor, dry cell batteries, and catalysts. Although the copper oxide(II) has been well known for efficient catalyst in C-N cross-coupling reaction, copper oxide(I) has not been highlighted. In this research, CuO and Cu2O nanoparticles (NPs) dispersed on the surface of grapehene oxide (GO) have been synthesized by impregnation method and their morphological and electronic structures have been systemically investigated using TEM, XRD, and XAFS. We demonstrate that both CuO and Cu2O on graphene presents efficient catalytic performance toward C-N cross coupling reaction. The detailed structural difference between CuO and Cu2O NPs and their effect on catalytic performance are discussed.

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Growth and analysis of Copper oxide nanowire

  • Park, Yeon-Woong;Seong, Nak-Jin;Jung, Hyun-June;Chanda, Anupama;Yoon, Soon-Gil
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.245-245
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    • 2009
  • l-D nanostructured materials have much more attention because of their outstanding properties and wide applicability in device fabrication. Copper oxide(CuO) has been realized as a p-type metal oxide semiconductor with narrow band gap of 1.2 -1.5eV. Copper oxide nanostructures can be synthesized by various growth method such as oxidation reaction, thermal evaporation thermal decomposition, sol-gel. and Mostly CuO nanowire prepared on the Cu substrate such as Copper foil, grid, plate. In this study, CuO NWs were grown by thermal oxidation (at various temperatures in air (1 atm)) of Cu metal deposited on CuO (20nm)/$SiO_2$(250nm)/Si. A 20nm-thick CuO layer was used as an adhesion layer between Cu metal and $SiO_2$

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Spectroscopic and Morphological Investigation of Copper Oxide Thin Films Prepared by Magnetron Sputtering at Various Oxygen Ratios

  • Park, Ju-Yun;Lim, Kyoung-A;Ramsier, Rex D.;Kang, Yong-Cheol
    • Bulletin of the Korean Chemical Society
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    • v.32 no.9
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    • pp.3395-3399
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    • 2011
  • Copper oxide thin films were synthesized by reactive radio frequency magnetron sputtering at different oxygen gas ratios. The chemical and physical properties of the thin films were investigated by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray diffraction (XRD). XPS results revealed that the dominant oxidation states of Cu were $Cu^0$ and $Cu^+$ at 0% oxygen ratio. When the oxygen ratios increased above 5%, Cu was oxidized as CuO as detected by X-ray induced Auger electron spectroscopy and the $Cu(OH)_2$ phase was confirmed independent of the oxygen ratio. The valence band maxima were $1.19{\pm}0.09$ eV and an increase in the density of states was confirmed after formation of CuO. The thickness and roughness of copper oxide thin films decreased with increasing oxygen ratio. The crystallinity of the copper oxide films changed from cubic Cu through cubic $Cu_2O$ to monoclinic CuO with mean crystallite sizes of 8.8 nm (Cu) and 16.9 nm (CuO) at the 10% oxygen ratio level.

Cu2O Thin Film Photoelectrode Embedded with CuO Nanorods for Photoelectrochemical Water Oxidation

  • Kim, Soyoung;Kim, Hyojin
    • Journal of the Korean institute of surface engineering
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    • v.52 no.5
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    • pp.258-264
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    • 2019
  • Assembling heterostructures by combining dissimilar oxide semiconductors is a promising approach to enhance charge separation and transfer in photoelectrochemical (PEC) water splitting. In this work, the CuO nanorods array/$Cu_2O$ thin film bilayered heterostructure was successfully fabricated by a facile method that involved a direct electrodeposition of the $Cu_2O$ thin film onto the vertically oriented CuO nanorods array to serve as the photoelectrode for the PEC water oxidation. The resulting copper-oxide-based heterostructure photoelectrode exhibited an enhanced PEC performance compared to common copper-oxide-based photoelectrodes, indicating good charge separation and transfer efficiency due to the band structure realignment at the interface. The photocurrent density and the optimal photocurrent conversion efficiency obtained on the CuO nanorods/$Cu_2O$ thin film heterostructure were $0.59mA/cm^2$ and 1.10% at 1.06 V vs. RHE, respectively. These results provide a promising route to fabricating earth-abundant copper-oxide-based photoelectrode for visible-light-driven hydrogen generation using a facile, low-cost, and scalable approach of combining electrodeposition and hydrothermal synthesis.

Color variation of copper glaze with the addition of tin oxide (산화주석 첨가에 따른 동화유약의 발색 변화)

  • No, Hyunggoo;Kim, Soomin;Kim, Ungsoo;Cho, Wooseok
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.27 no.5
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    • pp.243-248
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    • 2017
  • In this study copper glaze samples were prepared with varying amount of tin oxide, and the chromatic characteristics of glazes were explained on the results of spectrophotometric, crystalline phase, and microstructural analyses. The red color of copper glaze was dissipated with the addition of tin oxide and turned into achromatic color due to the decrease of CIEab values. Tin oxide homogeneously distributed in the glaze layer interfered with the red color generation coming from the growth of Cu nuclei, and formed an alloy with metal copper around bubbles. This resulted in the decrease of metal copper peak intensity with minor $Cu_2O$ peak. With the 3.79 % tin oxide addition the glaze was appeared as gray due to the black color CuO and Cassiterite $SnO_2$ phases.

Chromatic Characteristics of Copper Glaze as a Function of Copper Oxide Addition and Sintering Atmosphere

  • No, Hyunggoo;Kim, Soomin;Kim, Ungsoo;Cho, Wooseok
    • Journal of the Korean Ceramic Society
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    • v.54 no.1
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    • pp.61-65
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    • 2017
  • Examined in this study were the effects of copper oxide (II) addition and sintering conditions on the chromatic characteristics of copper glaze. Oxidatively sintered samples exhibited the negative increase of $CIEa^*$ and the positive increase of $CIEb^*$ with the increase of CuO concentration, leading to Green and Green-Yellow coloration. On the other hand, $CIEa^*$ and $CIEb^*$ of reductively sintered samples were positively increased in direct proportion. The green color of oxidatively sintered samples was originated from the $Cu^{2+}$ ions formed by the dissolution of CuO. The reductively sintered samples resulted in dull tone red color with low chroma. Such behavior seems to be influenced by the interplay of metal Cu aggregation, metal Cu globule, and $Cu_2O$ formed in the glaze layer through the redox interaction of CuO during the sintering process.

Graphene Based Cu Oxide Nanocomposites for C-N Cross Coupling Reaction

  • Choi, Jong Hoon;Park, Joon B.
    • Proceedings of the Korean Vacuum Society Conference
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    • pp.138.2-138.2
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    • 2013
  • Copper oxide is a multi-functional material being used in various research areas including catalysis, electrochemical materials, oxidizing agents etc. Among these areas, we have synthesized and utilized graphene based copper oxide nanocomposites (CuOx/Graphene) for the catalytic applications (C-N cross coupling reaction). Briefly, Cu precursors were anchored on the graphite oxide(GO) sheets being exfoliated and oxidized from graphite powder. Two different crystalline structures of Cu2O and CuO on graphene and GO were prepared by annealing them in Ar and O2 environments, respectively. The morphological and electronic structures were systemically investigated using FT-IR, XRD, XPS, XAFS, and TEM. Here, we demonstrate that the catalytic performance was found to depend on oxidative states and morphological structures of CuOx graphene nanocomposites. The relationship between the structure of copper oxides and catalytic efficiency toward C-N cross coupling reaction will be discussed.

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Effect of the Substrate Temperature on the Copper Oxide Thin Films

  • Park, Ju-Yeon;Gang, Yong-Cheol
    • Proceedings of the Korean Vacuum Society Conference
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    • pp.71-71
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    • 2010
  • Copper oxide thin films were deposited on the p-type Si(100) by r.f. magnetron sputtering as a function of different substrate temperature. The deposited copper oxide thin films were investigated by atomic force microscopy (AFM), scanning electron microscopy (SEM), spectroscopic ellipsometry (SE), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The SEM and SE data show that the thickness of the copper oxide films was about 170 nm. AFM images show that the surface roughness of copper oxide films was increased with increasing substrate temperature. As the substrate temperature increased, monoclinic CuO (111) peak appeared and the crystal size decreased while the monoclinic CuO (-111) peak was independent on the substrate temperature. The oxidation states of Cu 2p and O 1s resulted from XPS were not affected on the substrate temperature. The contact angle measurement was also studied and indicated that the surface of copper oxide thin films deposited high temperature has more hydrophobic surface than that of deposited at low temperature.

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Manufacturing of Copper(II) Oxide Powder for Electroplating from NaClO3 Type Etching Wastes

  • Hong, In Kwon;Lee, Seung Bum;Kim, Sunhoe
    • Journal of Electrochemical Science and Technology
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    • v.11 no.1
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    • pp.60-67
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    • 2020
  • In this study, copper (II) oxide powder for electroplating was prepared by recovering CuCl2 from NaClO3 type etching wastes via recovered non-sintering two step chemical reaction. In case of alkali copper carbonate [mCuCo3·nCu(OH)2], first reaction product, CuCo3 is produced more than Cu(OH)2 when the reaction molar ratio of sodium carbonate is low, since m is larger than n. As the reaction molar ratio of sodium carbonate increased, m is larger than n and Cu(OH)2 was produced more than CuCO3. In the case of m has same values as n, the optimum reaction mole ratio was 1.44 at the reaction temperature of 80℃ based on the theoretical copper content of 57.5 wt. %. The optimum amount of sodium hydroxide was 120 g at 80℃ for production of copper (II) oxide prepared by using basic copper carbonate product of first reaction. At this time, the yield of copper (II) oxide was 96.6 wt.%. Also, the chloride ion concentration was 9.7 mg/L. The properties of produced copper (II) oxide such as mean particle size, dissolution time for sulfuric acid, and repose angle were 19.5 mm, 64 second, and 34.8°, respectively. As a result of the hole filling test, it was found that the copper oxide (II) prepared with 120 g of sodium hydroxide, the optimum amount of basic hydroxide for copper carbonate, has a hole filling of 11.0 mm, which satisfies the general hole filling management range of 15 mm or less.

Bonding Mechanism of Direct Copper to Glass Seal in an Evacuated Tube Solar Collector (태양열 집열기에 사용되는 구리-유리관 접합기구)

  • 김철영;남명식;곽희열
    • Journal of the Korean Ceramic Society
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    • v.38 no.11
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    • pp.1000-1007
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    • 2001
  • In an evacuated tube solar collector, the stable sealing of the heat pipe to the glass tube is important for the collector to use for a long period of time. The sealing of copper tube to the glass is quite difficult because of the large differences in the physical and chemical properties of the two materials. In this study, therefore, a proper copper oxide layer was induced to improve the chemical bonding of the two materials, and the oxidation state of copper and the interface between copper and glass were examined by XRD, SEM and EDS. Its bonding strength was also measured. Cu$_2$O was formed when the bare copper was heat-treated under 600$^{\circ}C$, while CuO oxide layer was formed above that temperature. The bonding state of CuO to the copper was very poor. The borate treatment of the copper, however, extend the stable forming of Cu$_2$O layer to 800$^{\circ}C$. Borosilicate glass tube was sealed to a copper tube by Housekeeper method only when the sealing part was covered with Cu$_2$O layer. The bonding strength at the interface was measured 354.4N, its thermal shock resistance was acceptable.

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