• 공업화학
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• 제10권3호
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• pp.331-335
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• 1999

진이급속 산화물은 전기화학적 산소 발생/환원에 대한 bifunctional 촉매효과가 있어 금속-공기 이차전지와 같은 에너지 저장기술 개발에 연구대상이 되어왔다. Amorphous citrate precursor법을 이용하여 perovskite 구조를 갖는 La-Ca-Co 산화물과 pyrochlore 구조를 갖는 Pb-Ru 산화물을 제조하고, 이후 열처리법으로 표면적이 큰 전이금속 산화물 촉매분말을 제조하였다. PTFE 결합 기체확산형 전극의 충방전 실험을 통하여 전기화학적 산소발생/환원에 대한 좋은 촉매능을 가짐을 확인하였고, ${\pm}25mA/cm^2$의 전류밀도를 가하고 공기를 공급하면서 충방전 실험한 결과 100시간 이내에서 두촉매분말 모두 안정하였다. ACP법으로 제조한 perovskite 구조의 La0.6Ca0.4CoO3과 pyrochlore 구조의 Pb2Ru2O6가 이차전지용 공기전극 재료로 사용할 수 있음을 확인하였다.

• Bulletin of the Korean Chemical Society
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• 제35권6호
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• pp.1590-1600
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• 2014

Cinchona-based bifunctional catalysts have been extensively employed in the field of organocatalysis due to the incorporation of both hydrogen-bonding acceptors (quinuclidine) and hydrogen-bonding donors (e.g., alcohol, amide, (thio)urea and squaramide) in the molecule, which can simultaneously activate nucleophiles and electrophiles, respectively. Among them, cinchona-derived (thio)urea and squaramide catalysts have shown remarkable application potential by using their bifurcated hydrogen bonding donors in activating electrophilic carbonyls and imines. However, due to their bifunctional nature, they tend to aggregate via inter- and intramolecular acid-base interactions under certain conditions, which can lead to a decrease in the enantioselectivity of the reaction. To overcome this self-aggregation problem of bifunctional organocatalysts, we have successfully developed a series of sulfonamide-based organocatalysts, which do not aggregate under conventional reaction conditions. Herein, we summarize the recent applications of our cinchona-derived sulfonamide organocatalysts in highly enantioselective methanolytic desymmetrization and decarboxylative aldol reactions. Immobilization of sulfonamide-based catalysts onto solid supports allowed for unprecedented practical applications in the synthesis of valuable bioactive synthons with excellent enantioselectivities.

• Macromolecular Research
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• 제13권3호
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• pp.180-186
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• 2005

A novel bifunctional dye composed of spirobenzopyran and a cinnamoyl moiety was prepared and its photochromic behavior under the illumination of monochromatic UV light was investigated. This colorless bifunctional dye exhibits typical photochromism in both the film and in solution, through the structural and geometrical transformation from spirobenzopyran to merocyanine accompanied by a photocrosslinking reaction between the cinnamoyl moieties. Two kinds of photochemical reaction were selectively achieved by irradiation with monochromatic UV light at wavelengths of 275 and 365 nm, respectively. The effect of the selective photochemical reaction on the photochromism of the dye and its decaying behavior was investigated.

• 한국염색가공학회:학술대회논문집
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• 한국염색가공학회 2003년도 춘계학술대회 논문집
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• pp.37-42
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• 2003

Although fibre reactive dyes for wool were developed before those for cellulosic fibres, there are still limited ranges of fibre reactive dyes available for wool compared to those for cellulosic fbres. Since Fujioka and Abeta introduced the first mixed bifunctional reactive system in the early 1980s for cellulosic fibres, there has been some works on cotton and on silk. (omitted)

• Bulletin of the Korean Chemical Society
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• 제32권4호
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• pp.1195-1200
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• 2011

The catalytic enantioselective Mannich-type reaction promoted by chiral binaphthyl-modified bifunctional organocatalysts is described. The treatment of ${\alpha}$-fluoro-${\beta}$-ketoesters with N-Boc imines under mild reaction conditions afforded the corresponding ${\beta}$-aminated ${\alpha}$-fluoro-${\beta}$-ketoesters with excellent enantioselectivities (up to 98% ee).

• Bulletin of the Korean Chemical Society
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• 제32권1호
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• pp.291-295
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• 2011

The catalytic enantioselective conjugate addition reaction of $\alpha$-nitroacetate to $\alpha,\beta$-unsaturated enones promoted by chiral bifunctional organocatalysts is described. The treatment of $\alpha$-nitroacetate to $\alpha,\beta$-unsaturated enones afforded the corresponding Michael adducts with high enantioselectivity. The conjugate addition adducts are easily converted to chiral $\gamma$-nitro ketones and $\delta$-keto esters.

• Bulletin of the Korean Chemical Society
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• 제24권10호
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• pp.1538-1540
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• 2003

• Bulletin of the Korean Chemical Society
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• 제25권10호
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• pp.1567-1570
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• 2004

• 한국수소및신에너지학회논문집
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• 제15권1호
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• pp.23-31
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• 2004

For the fabrication of high efficient bifunctional electrocatalyst of oxygen electrode for PEM URFC (Polymer Electrolyte Membrane Unitized Regenerative Fuel Cell), which is a promising energy storage and conversion system using hydrogen as the energy medium, several bifunctional electrocatalysts were prepared and tested in a single cell URFC system. The catalysts for oxygen electrode revealed fuel cell performance in the order of Pt black > PtIr > PtRuOx > PtRu ~ PtRuIr > PtIrOx, whereas water electrolysis performance in the order of PtIr ~ PtIrOx > PtRu > PtRuIr > PtRuOx ~ Pt black. Considering both reaction modes PtIr was the most effective elctrocatalyst for oxygen electrode of present PEM URFC system. In addition, the water electrolysis performance was significantly improved when Ir or IrOx was added to Pt black just 1 wt.% without the decrease of fuel cell performance. Based on the catalyst screening and the optimization of catalyst composition and loading, the optimum catalyst electrodes for PEM URFC were $1.0mg/cm^2$ of Pt black as hydrogen electrode and $2.0mg/cm^2$ of PtIr (99:1) as oxygen electrode.

• 한국재료학회지
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• 제32권2호
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• pp.98-106
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• 2022

Metal-organic frameworks (MOFs) are widely used in various fields because they make it easy to control porous structures according to combinations of metal ions and organic linkers. In addition, ZIF (zeolitic imidazolate framework), a type of MOF, is made up of transition metal ions such as Co²⁺ or Zn²⁺ and linkers such as imidazole or imidazole derivatives. ZIF-67, composed of Co²⁺ and 2-methyl imidazole, exhibits both chemical stability and catalytic activity. Recently, due to increasing need for energy technology and carbon-neutral policies, catalysis applications have attracted tremendous research attention. Moreover, demand is increasing for material development in the electrocatalytic water splitting and metal-air battery fields; there is also a need for bifunctional catalysts capable of both oxidation/reduction reactions. This review summarizes recent progress of bifunctional catalysts for electrocatalytic water splitting and metal-air batteries using ZIF-67. In particular, the field is classified into areas of thermal decomposition, introduction of heterogeneous elements, and complex formation with carbon-based materials or polyacrylonitrile. This review also focuses on synthetic methods and performance evaluation.