• Journal of the Korean Chemical Society
• /
• v.50 no.1
• /
• pp.60-64
• /
• 2006

has been synthesized using the layered organic-inorganic hybrids, Cu2(OH)3(CH3COO)·H2O as a precursor. Cubic Cu2O is synthesized by reducing Cu2(OH)3(CH3COO)·H2O with glucose in water at 75oC. The effects of precursor and glucose are investigated. The structure of Cu2(OH)3(CH3COO)·H2O plays an important role in preparing the uniform size of Cu2O.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.16 no.4
• /
• pp.166-171
• /
• 2006

[ $Cu_2O$ ] and Cu have been synthesized from the layered organic-inorganic hybrid, $Cu_2(OH)_3(CH_3COO){\cdot}H_2O$, assisted by microwave irradiation. $Cu_2O$ is formed in aqueous glucose solution, while metallic Cu is formed in ethylene glycol by reduction of $Cu_2(OH)_3(CH_3COO){\cdot}H_2O$. The influence of microwave irradiation time and concentration of glucose on $Cu_2O$ particles formation and growth has been examined. The morphologies of $Cu_2O$ particles change from spheres with a few fm size to nanowires with diameter of 40 nm as increasing the microwave irradiation times.

• Journal of the Korean Electrochemical Society
• /
• v.10 no.1
• /
• pp.14-19
• /
• 2007

The corrosion and passivation of copper was investigated with the copper rotating disk electrode(Cu-RDE) in borate buffer solution. It has been observed with the mixed potential theory that the corrosion potential for the rotation rate increase under the convective diffusion condition was increased. It was suggested that the chemical intermediates and product 13. the copper oxidation were $Cu(OH)_{ads},\;{Cu(OH)_2}^-,\;Cu_2O,\;Cu(OH)_2,\;and\;CuO$.

• Korean Journal of Materials Research
• /
• v.22 no.9
• /
• pp.459-464
• /
• 2012

We investigated cleaning effects using $NH_4OH$ solution on the surface of Cu film. A 20 nm Cu film was deposited on Ti / p-Si (100) by sputter deposition and was exposed to air for growth of the native Cu oxide. In order to remove the Cu native oxide, an $NH_4OH$ cleaning process with and without TS-40A pre-treatment was carried out. After the $NH_4OH$ cleaning without TS-40A pretreatment, the sheet resistance Rs of the Cu film and the surface morphology changed slightly(${\Delta}Rs:{\sim}10m{\Omega}/sq.$). On the other hand, after $NH_4OH$ cleaning with TS-40A pretreatment, the Rs of the Cu film changed abruptly (${\Delta}Rs:till{\sim}700m{\Omega}/sq.$); in addition, cracks showed on the surface of the Cu film. According to XPS results, Si ingredient was detected on the surface of all Cu films pretreated with TS-40A. This Si ingredient(a kind of silicate) may result from the TS-40A solution, because sodium metasilicate is included in TS-40A as an alkaline degreasing agent. Finally, we found that the $NH_4OH$ cleaning process without pretreatment using an alkaline cleanser containing a silicate ingredient is more useful at removing Cu oxides on Cu film. In addition, we found that in the $NH_4OH$ cleaning process, an alkaline cleanser like Metex TS-40A, containing sodium metasilicate, can cause cracks on the surface of Cu film.

• Journal of Surface Science and Engineering
• /
• v.51 no.6
• /
• pp.360-364
• /
• 2018

A facile method to fabricate freestanding CuO nanoleaves and CuO nanowires-based films was demonstrated. $Cu(OH)_2$ nanoleaves and nanowires were prepared by a hydrolysis reaction in aqueous solution including pyridine and NaOH with the tailored concentrations at room temperature. The films of freestanding CuO nanoleaves and CuO nanowires can be successfully obtained via the simple vacuum infiltration following a thermal dehydration reaction. The morphologies and crystallinity of the $Cu(OH)_2$ nanoleaves/nanowires and CuO nanoleaves/nanowires were characterized by XRD, SEM, TEM and FT-IR. The films fabricated with freestanding CuO nanoleaves and nanowires in this study may be applicable for building high-efficiency organic binder-free devices, such as gas sensors, batteries, photoelectrodes for water splitting and so on.

• Bulletin of the Korean Chemical Society
• /
• v.31 no.8
• /
• pp.2283-2288
• /
• 2010

Nanostructured copper compounds were grown by electrochemical anodization of copper foil in aqueous NaOH under varying conditions including electrolyte concentration, reaction temperature, current density, and reaction time. Their morphology and atomic composition were investigated by using SEM, TEM, XRD, EDS and XPS. At the conditions ([NaOH] = 1 M, $20^{\circ}C$, $2\;mA\;cm^{-2}$), wire-like orthorhombic $Cu(OH)_2$ nanobundles with an average width of 100 - 300 nm and length of $10\;{\mu}m$ were synthesized with the preferential [100] growth direction. Furthermore, when the concentration decreased to 0.5 M NaOH, the 1D nanobundle structure became narrower and longer without any change in compositions or crystalline structure. Side reaction pathways appeared to compete with the 1D nanostructure formation channels: the formation of CuO nanoleaves at $50^{\circ}C$ via the sequential dehydration of $Cu(OH)_2$, CuO/$Cu_2O$ aggregates in 4 M NaOH, and $Cu_2O$ nanoparticles and CuO nanosheets at lower current density.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.15 no.5
• /
• pp.193-197
• /
• 2005

CuO has been synthesized using the layered organic-inorganic hybrids, $Cu_2(OH)_3(CH_3COO){\cdot}H_2O$ as precursor. The simple thermal decomposition of $Cu_2(OH)_3(CH_3COO){\cdot}H_2O$ is used without any external organic templates. This method provides large-scale production at a low cost of the single-crystalline CuO particles. The morphology of CuO aggregated particles is strongly dependent on structure of the precursor.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2018.06a
• /
• pp.141-141
• /
• 2018

Copper is one of the most abundant metals on earth. Its oxide (CuO) is an intrinsically p-type metal-oxide semiconductor with a bandgap ($E_g$) of 1.2-2.0 eV 1. Copper oxide nanomaterials are considered as promising materials for a wide range of applications e.g., lithium ion batteries, dye-sensitized solar cells, photocatalytic hydrogen production, photodetectors, and biogas sensors 2-7. Recently, high-density and uniform CuO nanostructures have been grown on Cu foils in alkaline solutions 3. In 2011, T. Soejima et al. proposed a facile process for the oxidation synthesis of CuO nanobelt arrays using $NH_3-H_2O_2$ aqueous solution 8. In 2017, G. Kaur et al. synthesized CuO nanostructures by treating Cu foils in $NH_4OH$ at room temperature for different treatment times 9. The surface treatment of Cu in alkaline aqueous solutions is a potential method for the mass fabrication of CuO nanostructures with high uniformity and density. It is interesting to compare the gas sensing properties among CuO nanomaterials synthesized by this approach and by others. Nevertheless, none of above studies investigated the gas sensing properties of as-synthesized CuO nanomaterials. In this study, CuO nanowalls versus nanoparticles were synthesized via the oxidation process of Cu foil in NH4OH solution at $50-70^{\circ}C$. The gas sensing properties of the as-prepared CuO nanoplates were examined with $C_2H_5OH$, $CH_3COCH_3$, and $NH_3$ at $200-360^{\circ}C$.

• Korean Journal of Soil Science and Fertilizer
• /
• v.31 no.2
• /
• pp.107-113
• /
• 1998

We investigated the effects of a long term application of soil amendments such as lime, silicate, compost, or combinations of these materials on the contents of Cu and Zn in paddy soil and brown rice. The results obtained from a sequential extraction of Cu and Zn in paddy soils and brown rice, using $H_2O$, $KNO_3$, $Na_2$-EDTA and $HNO_3$ and showed that the most of Cu and Zn were NaOH-extractable (organically bound form) and $HNO_3$-extractable (sulfide and residual form). Cu contents of NaOH and EDTA extractable increased with the long term application of compost while the contents of Zn extracted by $KNO_3$ was decreased even though $HNO_3$ extractable-Zn was prominent chemical form in paddy soils. The percentage and contents of Zn, extracted by $KNO_3$ for each combination treatment of soil amendments, was decreased but the contents of Cu was not affected. The content of NaOH extractable-Cu was proportionally increased with increase in organic matter content irrespective of the extractants used in this experiment. The contents of Zn and exchangeable K were also increased with increase in organic matter content. However, we could not find any relationship between the extractable forms of Cu and Zn, and CEC, OM. while increase in CEC, contents of cations, and organic matter decreased the content of Cu in brown rice.

• Korean Journal of Materials Research
• /
• v.32 no.5
• /
• pp.237-242
• /
• 2022

Designing and producing a low-cost, high-current-density electrode with good electrocatalytic activity for the oxygen evolution reaction (OER) is still a major challenge for the industrial hydrogen energy economy. In this study, nanostructured Fe-doped CuCo(OH)₂ was discovered to be a precedent electrocatalyst for OER with low overpotential, low Tafel slope, good durability, and high electrochemically active surface sites at reduced mass loadings. Fe-doped CuCo(OH)₂ nanosheets are made using a hydrothermal synthesis process. These nanosheets are clumped together to form a highly open hierarchical structure. When used as an electrocatalyst, the Fe-doped CuCo(OH)₂ nanosheets required an overpotential of 260 mV to reach a current density of 50 mA cm^-2. Also, it showed a small Tafel slope of 72.9 mV dec^-1, and superior stability while catalyzing the generation of O₂ continuously for 20 hours. The Fe-doped CuCo(OH)₂ was found to have a large number of active sites which provide hierarchical and stable transfer routes for both electrolyte ions and electrons, resulting in exceptional OER performance.