• Bulletin of the Korean Chemical Society
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• 제21권7호
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• pp.715-719
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• 2000

A ceramic powder of destructive adsorbent was synthesized by impregnating copper and manganese on the surface of silica aerosil@. In-site FTIR measurements on pulses of malodorant tert-butylmercaptan injected over the powder showed that rert-butylmercaptan dimerized into di-tert-hutyldisulfide on the surface of the adsorbent in an ambient condition. GC/MS measurement on the gas over the adsorbent showed no tert-butylmercaptan remaining, and showed only the dimerization product of di-tert-butyldisulfide. Most of the dimerization product, di-tert-butyldisulfide,remained on the surface of the adsorbent as physisorbed condense, and apparently Iowered the destruction efficiency by blocking the surface from the access by tert-butylmercaptan. Upon being heated above $100^{\circ}C$ it was observed that the physisorbed di-tert-butyldisulfide dissociated back into tert-butylmercaptan. tert-butylmercaptan physisorbed on the activated carbon, thereby no dimerization was occurring on the surface of the activated carbon. In an argn environment, the dimerization reaction was practically not occurring even on the surface of the adsorbent, indicating the free oxygen in air was also participating in the dimerization reaction. Water was identified as a by-product of the dimerization reaction. Possible reactions on the surface of the adsorbent were proposed.

• Bulletin of the Korean Chemical Society
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• 제28권3호
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• pp.413-416
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• 2007

The adsorption and surface reactions of NO on a VO/V(110) surface have been investigated using X-ray photoelectron spectroscopy (XPS), near-edge X-ray absorption fine structure, and temperature programmed desorption (TPD) technique. NO is molecularly adsorbed on VO/V(110) at 80 K. As the surface coverage of NO increases, the NO dimer is formed on the surface at 80 K. Both NO and (NO)2 are adsorbed on the surface with the N-O bond perpendicular to the surface. (NO)2 decomposes at ~100 K and the reaction product is desorbed as N2O. Decomposition of NO takes place when the surface temperature is higher than 273 K.

• Bulletin of the Korean Chemical Society
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• 제34권5호
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• pp.1477-1480
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• 2013

The Suzuki cross-coupling reactions proceeded in excellent yields when it was catalyzed by magnetically recyclable nanocatalyst. This nanocatalyst provided very high catalytic activity with low loading level (1 mol %), because the palladium nanoparticles were so small in size (~2 nm) and located on the surface of the nanocomposite. It was also easily recovered from the reaction mixture using a magnet and reused for six consecutive cycles.

• Bulletin of the Korean Chemical Society
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• 제35권4호
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• pp.1110-1116
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• 2014

The cuprous oxide cubes with the special porous surface constructed by nano-prisms have been successfully fabricated by a solvothermal method. The template-free method is simple and facile without any surfactant. The X-ray powder diffraction (XRD) pattern suggests that the as-prepared product is the pure primitive cubic $Cu_2O$. The effects of the experimental parameters, such as the reaction temperature, reaction time and the concentration of sodium acetate anhydrous, on the morphologies of the products were investigated in detail by the scanning electron microscopy (SEM). Based on the time-dependent experiments, the possible formation mechanism was proposed. Using photocatalytic degrading reactive dyes as the model reaction and xenon lamp to simulate sunlight, the $Cu_2O$ cubes with the porous surface might possess higher photocatalytic activity than those of the commercial $Cu_2O$ powder in the visible-light region, indicating the excellent photocatalytic performance.

• 대한화학회지
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• 제57권6호
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• pp.769-777
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• 2013

The effect of operating conditions (temperature and the partial pressures of H2 and CO) on the reaction rate of Fischer-Tropsch synthesis (FTS) were investigated by carrying out experiments according to a Box-Behnken design (BBD), and were mathematically modeled by using response surface methodology (RSM). The catalyst used was a nano-structured cobalt/manganese oxide catalyst, which was prepared by thermal decomposition. The rate of synthesis was measured in a fixed-bed micro reactor with $H_2/CO$ molar feed ratio of 0.32-3.11 and reactor pressure in the range of 3-9.33 bar at space velocity of $3600h^{-1}$ and a temperature range of 463.15-503.15 K, under differential conditions (CO conversion below 2%). The results indicated that in the present experimental setup, the temperature and the partial pressure of CO were the most significant variables affecting reaction rate. Based on statistical analysis the quadratic model of reaction rate of FTS was highly significant as p-value 0.0002.

• 한국수소및신에너지학회논문집
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• 제24권2호
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• pp.179-185
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• 2013

The behavior of surface film formation was greatly dependent on the speed of potential cycling. In $LiClO_4$ / EC + DEC, cyclic voltammetry results showed that the peaks originated from surface film formation on graphite electrode at the high charge-discharge rate was shifted to the lower potentials as the charge-discharge rate decrease. This indicates that surface films with different morphology and thickness were formed by different charge-discharge rate. Transmission electron microscopy (TEM) results indicated that the properties such as thickness and morphology of the surface film were greatly affected by the charge-discharge rate. Electrochemical impedance spectroscopy (EIS) showed that the resistance of surface film was affected by the speed of potential cycling. In addition, the charge transfer resistance was also dependent on the charge-discharge rate indicating that the charge transfer reaction was affected by the nature of surface film. TEM and EIS results suggested that the chemical property as well as the physical property of the surface film was affected by the charge-discharge rate.

• Bulletin of the Korean Chemical Society
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• 제19권7호
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• pp.733-737
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• 1998

Using an atom superposition and electron delocalization molecular orbital (ASED-MO) method, we have compared adsorption properties of adsorbates on the Pt(Ill) surface with the Pt(lll)/γ-Al203 surface in the ethylene hydrogenation reaction. In two-layer thick model systems, the calculated activation energy of the hydrogenation by the surface platinum hydride is equal to the energy by the hydride over supported platinum/γ-alumina. The transition structure on platinum is very close to the structure on the supported platinum/γ-alumina surface. Hydrogenation by the surface hydride on platinum can take place easily because the activation energy is about 0.5 eV less than hydrogenation by ethylidene. On supported platinum/,y-alumina the activation energy of the hydride mechanism is about 0.61 eV less than that of ethylidene mechanism. In one-layer thick model systems, the activation energy of hydrogenation by ethylidene is about 0.13 eV less than the activation energy of hydride reaction. The calculated activation energy by the hydride over the supported platinum y-alumina is 0. 24 eV higher than the platinum surface. We have found from this result that the catalytic properties of one-layer thick model systems have been influenced by the support but the two-layer thick model systems have not been influenced by the support.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1994년도 춘계학술대회 논문집
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• pp.38-41
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• 1994

The method of passivation for protecting the $Hg_{1-x}Cd_{x}$Te surface is important device fabrication process. Because the surface components are highly reactive leading to its chemical and electrical instability. Especially. the material of detecting for infrared radiation, of which composition is x=0.2 or 0.3, is narrow bandgap semi- conductor. The narrow bandgap semi conductors are largely governed by the properties of the semiconductor surface. The narrow bandgap semi-conductors are largely governed by the properties of the semiconductor surface. The electro-chemical processing of $Hg_{1-x}Cd_{x}$Te allows rigorous control of the surface chemistry and provides an in-suit monitor of surface reaction. So electro-chemical reduction at specific potential can be selectively eliminated the undesirable species on the surface and mainpulated to reproducibly attain the desired stoichiometry. This method shows to assess the quality of chemically treated good $Hg_{1-x}Cd_{x}$Te surface.

• Bulletin of the Korean Chemical Society
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• 제30권3호
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• pp.657-660
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• 2009

The surface of $Li[Ni_{0.8}Co_{0.15}Al_{0.05}]O_2$ cathode particle was modified by lanthanum based oxide to improve electrochemical property and thermal stability. The XRD pattern of surface layer was indexed with that of $La_4NiLiO_8$. The discharge capacity of modified electrode was higher than that of pristine sample, specially at fast charge-discharge rate and high cut-off voltage. In the DSC profile of the charged sample, the generation of heat by exothermic reaction was decreased by surface modification. Such enhancement may by attributed to the presence of stable lanthanum based oxide, which effectively suppressd the reaction between electrode and electrolyte on the surface of $Li[Ni_{0.8}Co_{0.15}Al_{0.05}]O_2$ electrode.

• Bulletin of the Korean Chemical Society
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• 제31권5호
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• pp.1275-1279
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• 2010

We have carried out the surface modification of photocatalytic $TiO_2$ with triethoxysilane through dehydrogenation reaction and characterized the modified photocatalyst by spectroscopic methods, such as FT-IR, solid-state $^{29}Si$ MAS NMR, XPS, and XRF, etc. We also examined photocatalytic activity of the immobilized photocatalytic titanium dioxide with triethoxysilane by decolorization reaction of dyes such as cong red and methylene blue under visible light. Dispersion test showed that the photocatalytic titanium dioxide immobilized with triethoxysilane group has kept higher dispersibility than titanium dioxide itself. No appreciable precipitation takes place even after standing for 24 h in the 4:6 mixture ratio of ethanol and water.