• Journal of Industrial and Engineering Chemistry
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• v.67
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• pp.486-496
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• 2018

Bimetallic Pd@Ni nanostructure exhibited enhanced co-catalytic activity for the selective hydrogenation of benzaldehyde compare to their monometallic counterparts. Impregnation of these mono/bimetallic nanostructures on mesoporous $TiO_2$ leads to several surface modifications. The bimetallic PNT-3 ($Pd_3@Ni_1/mTiO_2$) exhibited large surface area ($212m^2g^{-1}$), and low recombination rate of the charge carriers ($e^--h^+$). The hydrogenation reaction was analyzed under controlled experiments. It was observed that under UV-light irradiations and saturated hydrogen atmosphere the bimetallic PNT-3 photocatalyst display higher rate constant $k=5.31{\times}10^{-1}h^{-1}$ owing to reduction in the barrier height which leads to efficiently transfer of electron at bimetallic/$mTiO_2$ interface.

• Analytical Science and Technology
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• v.11 no.5
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• pp.360-365
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• 1998

We have studied structural characterization, electrical charge and discharge, and impedence properties for the $LiMn_2O_4$ synthesized by solid state reaction. From the X-ray diffraction results, diffraction patterns for compounds of the four kinds of $LiMn_2O_4$ compounds were observed to peaks of (111), (311), (004) and (400). Also, Small similar peaks (110), (222) and (313) were observed for sample C1 and C2. Concerning to new peaks of (113) and (331) for the sample C4, we can found that structural transitions were accompanied from C1 and C2 to C4 via C3 structure. A electrical charge and discharge data showed that efficiency of C1 was very poor state and efficiencies of C2 and C3 were about 60-70% of theoretical capacity. But, the C4 showed good charge and discharge properties of more than 70% of theoretical capacity. From the impedence properties for finding the effect of ions and electrons transfer of battery, C2 and C3 of high frequency of real number showed good electrical impedence properties.

• Journal of the Korean Chemical Society
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• v.17 no.1
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• pp.1-9
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• 1973

The purpose of this paper is to investigate the mechanism of Diels-Alder reaction by assuming pseudo molecular complex (PMC) which has characters both of ionic and radical bonds. We treated this complex quantum-chemically as an intermediate between the configuration without charge transfer (radical bond character) and the configuration corresponding to the charge transfer from Diene (R) to Dienophile (S) (ionic bond character). The wave function for the complex could be expressed as: ${\psi}_{complex} = {\psi}(R,S) +{ \rho}{\psi}(R^+,S^-)$ where ${\rho}$ is the extent of charge transfer which is a constant to measure the ionic character of PMC. It has been noticed that${\rho}$is related to the difference between Fr + Fr' and Fs + Fs' in free valence (F) when R is united to S through atom r in R to atom s in S and atom r' in R to atom s' in S, That is, ${\rho}{\alpha}$ ${\Delta}F = (Fr + Fr') - (Fs + Fs')$. We have calculated ${\Delta}F$values for more than forty Diels-Alder reactions. The calculated values of ${\Delta}F$ is reversely proportional to the values of Brown's paralocalization energy (Lp) as well as Dewar's differences of delocalization energy$({\Delta}Edeloc.)$ with good linearity. This approach also presents a way of predicting the possibility and the easiness of diene synthesis between any two conjugate compounds. According to the considerations, it could be concluded that Diels-Alder reaction takes place through the united ionic-radical mechanism rather than the separated ionic or radical mechanism.

• Bulletin of the Korean Chemical Society
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• v.33 no.4
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• pp.1259-1263
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• 2012

Two metal compounds, $[Co(phen)_2(H_2O)_2]{\cdot}2H_2SIP{\cdot}2H_2O$ 1 and $[Ni(phen)_3]{\cdot}2H_2SIP{\cdot}3H_2O$ 2, have been obtained by incorporating 1,10-phenanthroline (phen) and 5-sulfoisophthalic acid monosodium salt ($NaH_2SIP$) ligands under hydrothermal conditions. Meanwhile, the two compounds were characterized by element analysis, IR, XRD, TG-DTA and single-crystal X-ray diffraction. Both 1 and 2 present 3D supramolecular structures via O-H${\cdots}$O hydrogen bond interactions. Luminescent properties for 1 and 2 were also studied. The compound 1 has two fluorescence emission peaks centered at 398 nm attributed to the intraligand emission from the SIP ligand and at 438 nm assigned to the combined interaction of intraligand ${\pi}^*-{\pi}$ transitions of the phen ligand and ligand-to-metal-charge-transfer (LMCT) transitions (${\lambda}_{ex}$ = 233 nm). The compound 2 shows one emission band centered at 423 nm with a shoulder peak at 434 nm which may be originated from the intraligand ${\pi}^*-{\pi}$ transitions of the phen ligand (${\lambda}_{ex}$ = 266 nm).

• Korean Chemical Engineering Research
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• v.59 no.1
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• pp.35-41
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• 2021

Silicon is a promising next-generation anode material for lithium-ion battery, and it has been studied for commercialization due to the high theoretical capacity. However, it has problems of the volume change during charge-discharge and the poor electrical conductivity. To solve these problems, formation of SiO2 and carbon coating on the surface of silicon crystal were performed to protect the side reaction and enhance the electrical conductivity of silicon. CNT and CNF were also added to mitigate the volume change and increase the conductivity. Physical properties of asprepared samples were analyzed by XRD, SEM, and EDS. Electrochemical characteristics were investigated by electrical conductivity measurement, EIS, CV and cycle performance test. (Si/SiO2/C)+CNT&CNF showed high electrical conductivity and low charge-transfer resistance, and the capacity was 1528 mAh/g at 1st cycle and 1055 mAh/g at 50th cycle with 83% capacity retention.

• Applied Chemistry for Engineering
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• v.2 no.4
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• pp.311-329
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• 1991

Electrochemical behavior of surface active Osmium bipyridine complex adsorbed in a monomolecular layer on tin oxide electrodes by the Langmuir-Blodgett method was studied. Theoretical equation of cyclic voltammetry of electrode reactions for redox species adsorbed as monolayer form was discussed by reversible and quasi-reversible waves. The film was transferred onto the $SnO_2$ electrode surface and then amounts of charge on the electrode were measured in the technique of cyclic voltammetry. The electron transfer mediation of these monolayer with $Fe^{2+}$, TEMPOL and others were studied. And the cyclic voltammetry were simulated by taking into account the interaction parameters. From these values, we found it possible to fit almost all measured cyclic voltammograms with these parameters. The recent works and directions using LB method were introduced with various applicable field.

• KIEE International Transactions on Electrophysics and Applications
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• v.5C no.1
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• pp.28-32
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• 2005

In the Langmuir-Blodgett (LB) technique, a monolayer on the water surface is transferred onto a substrate, which is raised and dipped through the surface. From this, multilayers can be obtained in which constituent molecules are periodically arranged. The LB technique has attracted considerable interest in the fabrication of electrical and electronic devices. Many researchers have investigated the electrical properties of monolayer and multiplayer films. Dendrimers represent a new class of synthetic macromolecules characterized by a regularly branched treelike structure. Multiple branching yields a large number of chain ends that distinguish dendrimers from conventional star-like polymers and microgels. The azobenzene dendrimer is one of the dendritic macromolecules that include the azo-group exhibiting a photochromic character. Due to the presence of the charge transfer element of the azo-group and its rod-shaped structure, these compounds are expected to have potential interest in electronics and ptoelectronics, especially in nonlinear optics. In the present paper, we give pressure stimulation to organic thin films and detect the induced displacement current.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.05a
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• pp.52-54
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• 2006

In the Langmuir-Blodgett (LB) technique, a monolayer on the water surface is transferred onto a substrate, which is raised and dipped through the surface. From this, multi layers can be obtained in which constituent molecules are periodically arranged. The LB technique has attracted considerable interest in the fabrication of electrical and electronic devices. Many researchers have investigated the electrical properties of monolayer and multiplayer films. Dendrimers represent a new class of synthetic macromolecules characterized by a regularly branched treelike structure. Multiple branching yields a large number of chain ends that distinguish dendrimers from conventional star-like polymers and microgels. The azobenzene dendrimer is one of the dendritic macromolecules that include the azo-group exhibiting a photochromic character. Due to the presence of the charge transfer element of the azo-group and its rod-shaped structure, these compounds are expected to have potential interest in electronics and ptoelectronics, especially in nonlinear optics. In the present paper, we give pressure stimulation to organic thin films and detect the induced displacement current.

• Proceedings of the KIEE Conference
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• 2006.07c
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• pp.1330-1332
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• 2006

In the Langmuir-Blodgett (LB) technique, a monolayer on the water surface is transferred onto a substrate, which is raised and dipped through the surface. From this, multilayers can be obtained in which constituent molecules are periodically arranged. The LB technique has attracted considerable interest in the fabrication of electrical and electronic devices. Many researchers have investigated the electrical properties of monolayer and multiplayer films. Dendrimers represent a new class of synthetic macromolecules characterized by a regularly branched treelike structure. Multiple branching yields a large number of chain ends that distinguish dendrimers from conventional star-like polymers and microgels. The agobenzene dendrimer is one of the dendritic macromolecules that include the azo-group exhibiting a photochromic character. Due to the Presence of the charge transfer element of the azo-group and its rod-shaped structure, these compounds are expected to have potential interest in electronics and ptoelectronics, especially in nonlinear optics. In the present paper, we give pressure stimulation to organic thin films and detect the induced displacement current.

• Proceedings of the KIEE Conference
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• 2004.11a
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• pp.209-211
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• 2004

In the Langmuir-Boldgett(LB) technique, a monolayer on the water surface is transferred on to a substrate, which is raised and dipped through the surface, and one can obtain multilayers in which constituent molecules periodically are arranged in layer. The LB technique has attracted considerable interest in the fabrication of electrical and electronic device, e.g.. Many researchers have investigated the electrical properties of monolayer and multiplayer films. Dendrimers represent a new class of synthetic macromolecules sharacterized by a regularly branched treelike structure. Multiple branching yields a large number of chain ends, which distinguishes dendrimers from conventional starlike polymers and microgels. Azobenzene dendrimer is one of the dendritic macromolecules that includes the azo-group which exhibits a photochromic character. Due to the presence of the charge transfer part, the azo-group, and having a rod-shaped structure, these compounds are expected to have the potential interest in electronics and ptoelectronics, especially in nonlinear optics. In the present paper, we give a pressure stimulation into organic thin films and detect the induced displacement current.