• Korean Chemical Engineering Research
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• v.40 no.6
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• pp.664-668
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• 2002

In this work, the catalytic reduction mechanisms of NO over ACFs/copper prepared by electrolytic copper plating has been studied. It was found that copper content on carbon surfaces increased with increasing the plating time. However, a slightly gradual decrease of adsorption properties, such as, BET specific surface area, was observed in increasing the plating times within the range of well-developed micropore structures. As experimental results, nitric oxide was converted into the nitrogen and oxygen on ACFs and ACFs/copper catalyst surfaces at $500^{\circ}C$. Especially, the surfaces of ACFs/copper catalyst were found to scavenge the oxygen released by catalytic reduction of NO, which could be explained by the presence of another nitric oxide reduction mechanism between ACFs and ACFs/copper catalysts.

• Clean Technology
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• v.20 no.1
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• pp.28-34
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• 2014

In this study, we synthesized $TiO_2$ supports with nanosized crystalline structure by solvothermal method and prepared $TiO_2$ supported Pd-Cu catalysts. It was shown that the crystalline size of $TiO_2$ support in the catalyst influenced on the catalytic activity of nitrate reduction in water. The catalyst with the smaller crystalline size of $TiO_2$ support presented faster nitrate reduction rate, but had low nitrogen selectivity due to high pH environment of reaction medium during the reaction. Through injection of carbon dioxide as a pH buffer, the nitrogen selectivity increased by about 60%. Furthermore, we investigated that the relationships between the catalytic performance and the physicochemical properties of the prepared catalysts characterized by $N_2$ adsoprtion-desorption, X-ray diffraction (XRD), $H_2$-temperature programmed reduction (TPR), X-ray photoelectron spectroscopy (XPS).

• Applied Chemistry for Engineering
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• v.21 no.1
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• pp.1-5
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• 2010

Cu(II)-organic complexes were synthesized with Lewis base organic ligands including diamine, aminothiol, and dithiol to determine the reactivity for DFP hydrolysis. Results show that the aminothiol catalyst enhances the hydrolysis of DFP in three folds compared to diamine type because aminothiol has higher basicity than diamine. Due to low solubility of Cu(II)(1,2-ethane dithiol)$(NO_3)_2$, it is impossible to compare directly the rates in homogeneous condition. However, the rate of dithol complex is even 1.6 times faster than that of the diamine type. The reactivity of zeolite for DFP hydrolysis is also evaluated. NaY type does not promote the hydrolysis, but RuNaY shows relatively lower reactivity than those of Cu(II)-organic ligands complexes.

• Transactions of the Korean hydrogen and new energy society
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• v.18 no.2
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• pp.116-123
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• 2007

[ $La_{0.5}Ce_{0.5}Co_{1-x}Cu_xO_{3-{\alpha}}$ ](X=0, 0.1, 0.3, 0.5) perovskites were prepared by coprecipitation method at pH 7 or pH 11 and its catalytic activity of selective CO oxidation was investigated. The characteristics of these catalysts were analyzed by $N_2$ adsorption, X-ray diffraction(XRD), SEM, $O_2$-temperature programmed desorption(TPD). The pH value at a preparation step made effect on particle morphology. The smaller particle was obtained with a condition of pH 7. The better catalytic activity was observed using catalysts prepared at pH 7 than pH 11. The maximum CO conversion of 98% was observed over $La_{0.5}Ce_{0.5}Co_{0.7}Cu_{0.3}O_{3-{\alpha}}$ at $320^{\circ}C$. Below $200^{\circ}C$, the most active catalyst was $La_{0.5}Ce_{0.5}Co_{0.9}Cu_{0.1}O_{3-{\alpha}}$, of which conversion was 92% at $200^{\circ}C$. By the substitution of Cu, the evolution of ${\alpha}$-oxygen was remarkably enhanced regardless of pH value at preparation step according to $O_2$-TPD. Among the different ${\alpha}$-oxygen species, the oxygen species evolved between $400^{\circ}C$ and $500^{\circ}C$, gave the better catalytic performance for selective CO oxidation including $La_{0.5}Ce_{0.5}CoO_3$ in which Cu was absent.

• Clean Technology
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• v.20 no.1
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• pp.7-12
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• 2014

Hydrogenolysis of glycerol to propylene glycol was performed over binary and ternary metal oxide catalysts. The conversion of glycerol and selectivity to propylene glycol were increased on Cu/Zn and Cu/Cr mixed oxides compared to pure CuO and ZnO oxides. The addition of alumina into Cu/Zn mixed oxide very highly increased the conversion of glycerol and selectivity to propylene glycol. The conversion of glycerol was increased with increasing the reaction temperature but the selectivity to propylene glycol was shown to have maximum value at $200^{\circ}C$ and then decreased at $250^{\circ}C$. The conversion of glycerol and selectivity to propylene glycol were decreased with increasing the glycerol concentration.

• Journal of the Korean Electrochemical Society
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• v.27 no.1
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• pp.15-31
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• 2024

The antimalarial drug hydroxychloroquine sulphate (HCQ) has taken much attention during the first COVID-19 pandemic phase for the treatment of severe acute respiratory infection (SARI) patients. Hence it is interest to study the electrochemical properties and photocatalytic degradation of the HCQ drug. Copper oxide (CuO) nanoparticles, graphene oxide (GO) and CuO/GO NC (nanocomposite) modified carbon paste electrodes (MCPE) are used for the detection of HCQ in an aqueous medium. Electrochemical behaviour of HCQ (20 μM) was observed using CuO/MCPE, GO/MCPE and CuO/GO NC/MCPE in 0.1 M phosphate buffer at pH 7 with a scan rate of 20 to 120 mV s^-1 by cyclic voltammetry (CV). Differential pulse voltammetry (DPV) of HCQ was performed for 0.6 to 16 μM HCQ. The CuO/GO NC/MCPE showed a reasonably good sensitivity of 0.33 to 0.44 μA μM cm^-2 with LOD of 69 to 92 nM for HCQ. Furthermore, the CuO/GO NC was used as a catalyst for the photodegradation of HCQ by monitoring its UV-Vis absorption spectra. About 98% was degraded in about 34 min under visible light and after 4 cycles it was 87%. The improved photocatalytic activity may be attributed to decrease in bandgap energy and enhanced ability for the electrons to migrate. Thus, CuO/GO NC showed good results for both sensing and degradation applications as well as reproducibility.

• Applied Chemistry for Engineering
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• v.25 no.5
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• pp.531-537
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• 2014

A catalytic plasma reactor was employed for the oxidation of isopropyl alcohol (IPA) classified as a volatile organic compound (VOC). Copper oxide (Cu : 0.5% (w/w)) supported on a multichannel porous ceramic consisting of ${\alpha}-Al_2O_3$ was used as a catalyst, which was directly exposed to the plasma created in it. The effects of discharge voltage and reaction temperature on the concentrations of IPA and its byproducts were examined to understand the behavior of the catalytic plasma reactor. Without thermal insulation, the reactor temperature increased up to $120^{\circ}C$ at an applied voltage of 17 kV (discharge power : 28 W), and the IPA at a flow rate of $1L\;min^{-1}$ ($O_2$ : 10% (v/v); IPA : 1000 ppm) was completely removed. At temperatures below $120^{\circ}C$, however, besides the desirable product $CO_2$, several unwanted byproducts such as acetone, formaldehyde and CO were also formed from IPA. On the other hand, when the reactor was thermally insulated, the plasma discharge increased the temperature up to $265^{\circ}C$ under the same condition and most of IPA was oxidized to $CO_2$. Without loading CuO on the ceramic support, the plasma discharge in the thermally insulated reactor produced nearly equal amounts of $CO_2$ and CO. On comparison, with the catalyst alone (temperature : $265^{\circ}C$), more than 70% of the removed IPA was simply converted into another type of VOC (acetone), indicating that the catalyst assisted by the plasma is more effective in the oxidation of IPA than that of the catalyst-alone process.

• Clean Technology
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• v.23 no.2
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• pp.172-180
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• 2017

Thermodynamic evaluation indicates that nearly 100% conversion of elemental mercury to oxidized mercury can be attained by HCl of several tens of ppm level at the temperature window of SCR reaction. Cu-, Fe-, Mn-chloride loaded $V_2O_5-WO_3/TiO_2$ catalysts revealed good NO removal activity at the operating temperature window of SCR process. The catalysts with high desorption temperature indicating adsorption strength of $NH_3$ revealed higher NO removal activity. The HCl fed to the reaction gases promoted the oxidation of mercury. However, the activity for the oxidation of elemental mercury to oxidized mercury by HCl was suppressed by $NH_3$ inhibiting the adsorption of HCl to catalyst surface under SCR reaction condition containing $NH_3$ for NO removal. Metal chloride loaded $V_2O_5-WO_3/TiO_2$ catalysts showed much higher activity for mercury oxidation than $V_2O_5-WO_3/TiO_2$ catalyst without metal chloride under SCR reaction condition. This is primarily attributed to the participation of chloride in metal chloride on the catalyst surface promoting the oxidation of elemental mercury.

• Korean Chemical Engineering Research
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• v.52 no.2
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• pp.247-255
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• 2014

$La_{0.8}Sr_{0.2}CuO_3$ powder with the perovskite structure was prepared as electrode catalyst using citrate method. Porous electrode was made with as-prepared catalyst, carbon as supporter and polytetrafluoroethylene (PTFE) as hydrophobic binder. As results of potentiostatic electrolysis with potential of -1.5~-2.5 V vs. Ag/AgCl in 0.1, 0.5 and 1.0 M KOH at 5 and $10^{\circ}C$ on the porous electrode, liquid products were methanol, ethanol, 2-propanol and 1, 2-butanol regardless reaction temperature, while gas products were methane, ethane and ethylene at $5^{\circ}C$, and methane, ethane and propane at $10^{\circ}C$ respectively. Optimal potentials for $CO_2$ reduction in the view of over all faradic efficiency were high values (-2.0 and -2.2 V) for gas products whereas low potential (-1.5 V) for liquid products regardless of concentration and temperature.

• Resources Recycling
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• v.11 no.2
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• pp.3-13
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• 2002

The characteristics of cyanide decomposition in aqueous phase by hydrogen peroxide have been explored in an effort to develop a process to recycle waste water. The self-decomposition of $H_2O$$_2$at pH 10 or below was minimal even in 90 min., with keeping about 90% of $H_2O$$_2$undissociated. On the contrary, at pH 12 only 9% of it remained during the same time. In the presence of copper catalyst at 5 g Cu/L, complete decomposition of $H_2$O$_2$was accomplished at pH 12 even in a shorter time of 40 min. The volatility of free cyanide was decisively dependent on the solution pH: the majority of free cyanide was volatilized at pH 8 or below, however, only 10% of it was volatilized at pH 10 or above. In non-catalytic cyanide decomposition, the free cyanide removal was incomplete in 300 min. even in an excessive addition of $H_2$$O_2$at a $H_2$$O_2$/CN molar ratio of 4, with leaving behind about 8% of free cyanide. On the other hand, in the presence of copper catalyst at a Cu/CN molar ratio of 0.2, the free cyanide was mostly decomposed in only 16 min. at a reducedH202/CN molar ratio of 2. Ihe efnciency of HBO2 in cyanide decomposition decreased with increasing addition of H2O2 since the seu-decomposition rate of $H_2$$O_2$increased. At the optimum $H_2$$O_2$/mo1ar ratio 0.2 of and Cu/CN molar ratio of 0.05, the free cyanide could be completely decomposed in 70 min., having a self-decomposition rate of 22 mM/min and a H$_2$$O_2$ efficiency of 57%.