• Journal of the Korean Chemical Society
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• v.57 no.4
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• pp.483-488
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• 2013

Copper oxide (CuO) was synthesized from $CuCl_2$ by solution method. Anatase $TiO_2$ particle was dispersed into the solution before preparing CuO, so that $TiO_2$/CuO heterojunction was created through the nucleation of CuO onto the $TiO_2$ surface. Some amount of CuO was reduced to $Cu_2O$ by treating glucose into the solution, thereby preparing $TiO_2/Cu_xO$ complex. The obtained $TiO_2/Cu_xO$ complex showed advanced phtocatalytic activity under the sun light compared with the P-25 sample. In addition, the the $TiO_2/Cu_xO$ complex showed excellent antipathogenic effect.

• Journal of the Korean Ceramic Society
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• v.32 no.1
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• pp.83-89
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• 1995

YBa2Cu3O7-$\delta$, Y2BaCuO5, and binary compounds in the Ba-Cu-O system with the nominal composition of Ba2CuO3, BaCuO2, Ba3Cu4O7, Ba3Cu5O8 were synthesized to investigate the heat evolutions and crystalline phases in the hydration reaction of orthorhombic YBa2Cu3O7-$\delta$ phase. The observed crystalline phases were YBa2Cu3O7-$\delta$, Y2BaCuO5, and BaCuO2, or Ba2Cu3O5＋x, and some amount of noncrystalline phase in the Ba-Cu system comounds. In contact with distilled water, YBa2Cu3O7-$\delta$ and Y2BaCuO5 did not have considerable heat liberation, but in the binary compounds of the Ba-Cu-O system, the amount of total heat liberation was increased with respect to the Cu content. It might be that the reaction of high temperature superconductor YBa2Cu3O7-$\delta$ with water and/or moisture originated from the unusual oxidation state of Cu ion and the presence of amorphous Ba-Cu oxide compound. The degradation of high Tc superconductor by moisture and water could be controlled by restricting the heterogeneous distribution of Tc comlposition and the formation of second phase, such as stable Y2BaCuO5, and the resulting unstable Ba-Cu oxide compound.

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

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.220-220
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• 2003

최근, Cu기판 위에 YBaCuO$_{7-x}$ 초전도체를 입혀 초전도 선재를 제작하려는 연구가 이루어지고 있으며 이 과정에서 CuO와 Cu$_2$O가 생성된다는 보고가 있다. CuO 및 Cu$_2$O의 생성은 초전도 선재의 전기전도적 특성 및 기계적 특성에 상당한 영향을 끼칠 수 있다. 따라서 CuO와 Cu$_2$O에 대한 연구가 필요하다고 할 수 있다. 본 연구에서는 DV-X$\alpha$ 분자궤도법을 통해 CuO와 Cu$_2$O에 대한 (Cu$_{29}$ O$_{58}$ )$^{58-}$ , (Cu$_{52}$ O$_{19}$ )$^{14+}$ 모델을 이용하여 전자상태계산을 하였다. CuO, Cu$_2$O의 valence orbital level 구조 및 DOS (Density of State)를 통해 Cu원자와 O원자간의 공유결합 세기를 측정하였으며 CuO, Cu$_2$O 서로간의 차이점을 분석하였다.

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

• Korean Journal of Materials Research
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• v.2 no.4
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• pp.241-247
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• 1992

The direct bonding of Cu to $Al_2O_3$, employing the $Cu-Cu_2$O eutectic skin melt, is investigated. The bonding force and interface structure of samples prepared by oxidation at $1015^{\circ}C$ in $1.5{\times}10^{-1}$torr followed by bonding at 107$5^{\circ}C$ under $10_{-3}$ torr vacuum have been studied using peeling test, SEM, EDS and XRD. It has been found that the optimal strength is obtained for 3 minutes of oxidation while the adhesion force is decreased with oxidation shorter or longer than 3 minutes. The rupture occured at alumina-eutectic interface. Fractured surface of $Al_2O_3$covered with $Cu_2$O nodules pulled out of the Cu indicates that bonding strength is governed by $Cu-Cu_2$O interface and not by $Cu_2$O-A$l_2O_3$interface. The bonding force is slightly increased with bonding time and the reaction phases of CuA$l_2O_4$and $CuAlO_2$are formed at interface during the bonding.

• Clean Technology
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• v.19 no.2
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• pp.128-133
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• 2013

Catalytic combustion of benzene over $CeO_2$-supported copper oxides has been investigated. The supported copper oxides catalysts were prepared using ball mill method and characterized by XRD, FT-IR, TEM and TPR. In the CuO/$CeO_2$ catalysts prepared using ball mill method, highly dispersed copper oxide species were shown at high loading ratio. The CuO/$CeO_2$ prepared using ball mill method showed the higher activity than those prepared using impregnation method. The catalytic activity increased with an increase in the CuO loading ratio, 10 wt% loaded CuO/$CeO_2$ catalyst giving the highest activity. In addition, the promoting of 10 wt% loaded CuO/$CeO_2$ catalyst with $Fe_2O_3$ and CoO enhanced the dispersion of CuO and then increased the catalytic activity.

• Bulletin of the Korean Chemical Society
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• v.12 no.6
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• pp.606-612
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• 1991

We have carried out an extended Huckel calculation to rationalize the role of $CuO_3$ chains and the size effect of the charged model clusters for the following charged model culsters : ${{Cu_6}{O_{21}}^{28-},\;{{Cu_6}{O_{22}}^{30-}\;,{{Cu_9}{O_{30}}^{39-}\;,{{Cu_9}{O_{32}}^{43-}\;,{{Cu_{12}{O_{38}}^{48-}\;,{{Cu_{15}{O_{50}}^{65-}\;,{{Cu_{18}{O_{54}}^{66-}\;,{{Cu_{18}{O_{55}}^{68-}\;,{{Cu_{24}{O_{70}}^{84-}\;and\;{{Cu_{27}{O_{78}}^{93-}$ for high-$T_c$ superconductor $YBa_2Cu_3O_7$: ${{Cu_6}{O_{18}}^{22-}\;,{{Cu_9}{O_{26}}^{31-}}\;,{{Cu_{12}{O_{32}}^{36-}\;,{{Cu_{15}{O_{42}}^{49-}\;,{{Cu_{18}{O_{46}}^{50-}\;,{{Cu_{24}{O_{60}}^{64-}\;and\;{{Cu_{27}{O_{66}}^{69-}$ for insulator $YBa_2Cu_3O_6$. The results show that the electronic structures and properties of the charged model clusters relating to high-$T_c$ superconductor are very sensitive to the size change of the clusters with various environmental effects, wherease those of the charged model clusters for insulator $YBa_2Cu_3O_6$ are monotonous to the size change. The $CuO_3$ chains along the b-direction may yield cooperative electronic coupling with the $CuO_2$ layers in determining both conducting and superconducting properties of $YBa_2Cu_3O_{7-x}$ system.

• Journal of the Korean Ceramic Society
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• v.32 no.9
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• pp.1040-1046
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• 1995

The formation free energy of Y2Cu2O5 was measured by the partial ion exchanged (Cu2+, Na+)-$\beta$/$\beta$"-Al2O3 as solid state electrolyte. The formation cell was built as follows: Pt(O2)/Y2Cu2O5＋Y2O3//(Cu2+, Na+)-$\beta$/$\beta$"-Al2O3//CuO/(O2)Pt The virtual formation formation formula, and the calculated formation free energy of Y2Cu2O5 as a function of temperature are as follows: 2CuO＋Y2O3=Y2Cu2O5 ΔfG0/kJ.mol-1=13.19-16.25*10-3T/K.5*10-3T/K.

• Bulletin of the Korean Chemical Society
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• v.10 no.6
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• pp.504-509
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• 1989

The effect of oxygen-deficiency on the charge distributions and orbital energies for small copper oxide clusters representing the superconducting materials $YBa_2Cu_3O_x (6{\leq}x{\leq}7)$ were investigated by the extended Huckel molecular orbital (EHMO) method with the tight-binding model. Our calculations show +3 oxidation state of Cu(1) in the $CuO_3$ chain and +2 or +1 of Cu(2) in the $CuO_2$ layers for $YBa_2Cu_3O_7$ with the nominal charge of $Cu_3$ = +7 (or +5), while for $YBa_2Cu_3O_6$ +1 oxidation state of Cu(1) and +3 (or +2) of Cu(2) in the $CuO_2$ layers with the nominal charge of $Cu_3$ = +7 (or +5). For $Cu_3O_{12}$ cluster representing $YBa_2Cu_3O_7$ with the nominal charge of $Cu_3$ = +7 the Cu(2) $d_{{x^2}-{y^2}}$ orbitals in the $CuO_2$ layers is a typical Jahn-Teller $d^9$ system with the partial hole and the Cu(1) $d_{{_z2}-{_y2}}$ orbital in the $CuO_3$ chain contains hole occupancy. For $Cu_3O_{10}$ cluster representing $YBa_2Cu_3O_6$ with the nominal charge of Cu = +5 the orbital character of the highest partially occupied MO (HPOMO) and the lowest completely unoccupied MO (LCUMO) of $Cu_3O_{12}$ representing $YBa_2Cu_3O_7$ with the nominal charge of $Cu_3$ = +7 is reversed, and the character of Cu(1) $d{{x^2}-{y^2}}$ orbital of LCUMO of the $Cu_3O_{12} $cluster is vanished. It is suggested that the local crystal field environment of Cu(1) by the oxygens in the Cu(1) chain may play a vital role in conductivity and superconductivity, either alone or through cooperative electronic coupling with the Cu(2) layers in $YBa_2Cu_3O_7.$.