• Proceedings of the Materials Research Society of Korea Conference
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• 2012.05a
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• pp.71.1-71.1
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• 2012

Proton Exchange Membrane Fuel Cells (PEMFCs) have been of great interest particularly in the automobile industries because of their high energy density and low pollutant emission. However, some of the issues such as, the necessarily high contents of Pt catalysts and their slow kinetics of cathode oxygen reduction reaction remain as obstacles in the commercialization of the PEMFC. In this presentation, after brief explanation on basic principles of PEMFC and its application to FC vehicles, recent researches to improve the activity and durability of Pt-based nano catalysts toward oxygen reduction will be introduced. It covers size and shape control of Pt nano particle, binary and ternary Pt-M alloys, novel core-shell nano structures of Pt, and a little bit about non-Pt catalysts. Strategies and methodologies for design and synthesis of novel catalysts will also be included.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.3 no.2
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• pp.116-121
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• 2017

To overcome the low reactivity and solubility of alkali metal fluorides (MFs), various types of phase transfer catalysts (PTCs) have been developed over the last decades. However, since the fluoride activated by such PTC sometimes has a strong basicity, it may cause various side reactions such as elimination reaction or hydroxylation reaction in the nucleophilic fluorination reaction. Also, they may cause separation problems in the compound purification process. In recent advanced study, various PTCs have been developed to solve these problem of conventional catalyst. In this review, we would like to introduce three kinds of novel multifunctional organic catalysts such as bis-tert-alcohol-functionalized crown-6-calix[4]arene (BACCA), easy separable pyrene-tagged ionic liquid (PIL) by reduced graphene oxide (rGO), and tri-tert-butanolamine organic catalyst.

• Journal of the Korean Electrochemical Society
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• v.8 no.1
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• pp.6-11
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• 2005

Direct borohydrides fuel cell (DBFC) was emerged to complement the problem of DMFC's low performance and methanol crossover to the cathode and to apply the fuel cell to portable and mobile devices. In this study, the characteristics of novel catalysts was tested to establish the electrode preparation process of DBFC. Pt black and carbon supported-Pt by paste method were used as the cathode catalysts. Pt black, carbon supported-Au and $AB_5$ alloy were used as the anode catalysts. The characteristics of the electrodes were analyzed by XRD, SEM, EDS. The performance test of single cell using the electrodes were carried out in order to evaluate the electrode performance. In the result, the maximum power output was obtained as 366 mW/mg when using Pt/C as anode and cathode catalysts.

• 한국전기화학회:학술대회논문집
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• 2003.07a
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• pp.89-95
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• 2003

Fuel processing is an enabling technology for faster commercialization under lack of hydrogen infrastructures. It has been reported that the development of novel catalysts that are active and selective for hydrocarbon reforming reactions. It has been realized, however, that with pellet or conventional honeycomb catalysts, the reforming process is mass transport limited. This paper reports the development of catalyst structures with microchannels that are able to reduce the diffusion resistance and thereby achieve the same production rate within a smaller reactor bed. These microchannel reforming catalysts were prepared and tested with natural gas and gasoline-type fuels in a microreactor (1-cm dia.) at space velocities of up to 250,000 per hour. These catalysts have also been used in engineering-scale reactors (10 kWe, 7-cm dia.) with similar product qualities. Compared to pellet catalysts. the microchannel catalysts enable a nearly 5-fold reduction in catalyst weight and volume.

• Bulletin of the Korean Chemical Society
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• v.27 no.7
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• pp.1031-1037
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• 2006

New nickel complexes containing novel tetradentate ligands, 4,5-substituted-1,2-bis(pyridine-2-carboxamide)-benzene ligands but lacking alkyl or halide ligands in the coordination sphere have been prepared. They were activated with MMAO (modified methylaluminoxane) to be proven as efficient catalysts for the polymerization of norbornene. Both electron-donating and -withdrawing substituents on the benzene ring and polar solvents enhance the catalytic activity for olefin polymerization. Improvement in thermal stability of the complexes was observed. Some of these complexes were crystallographically determined to have square planar geometry. A plausible mechanism involving dissociation of ligands is proposed.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.873-875
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• 2009

Middle distillate was produced by the hydrocracking of F-T wax on the zeolite catalysts. Novel metal loaded zeolite catalysts had good performance for hydrocracking of F-T wax. 2 wt.% Platinum loaded H-Y zeolite catalyst showed the highest selectivity of middle distillate and conversion of F-T wax. H-Y zeolite had more strong acidity site and large pore than that of another zeolite catalyst. So, H-Y zeolilte catalyst showed the best activity for hydrocracking of F-T wax.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.10a
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• pp.340-340
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• 1998

• Clean Technology
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• v.22 no.4
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• pp.250-257
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• 2016

As an attempt to replacing petroleum-based chemicals with bio-based ones, synthesis of furfural from biomass-derived xylose attracts much attention in recent days. Conventionally, furfural from xylose has been produced via the utilization of highly corrosive, toxic, and environmentally unfriendly mineral acids such as sulfuric acid or hydrochloric acid. In this study, microwave-assisted biphasic reaction process in the presence of novel bio-based heterogeneous acid catalysts was developed for the eco-benign and effective synthesis of furfural from xylose. The microwave was irradiated for reaction acceleration and a biphasic system consisting of $H_2O$ : MIBK (1 : 2) was designed for continuous extraction of furfural into the organic phase in order to reduce the undesired side products formed by decomposition/condensation/oligomerization in the acidic aqueous phase. Moreover, sulfonated amorphous carbonaceous materials were prepared from wood powder, the most abundant lignocellulosic biomass. The prepared catalysts were characterized by FT-IR, XPS, BET, elemental analysis and they were used as bio-based heterogeneous acid catalysts for the dehydration of xylose into furfural more effectively. For further optimization, the effect of temperature, reaction time, water/organic solvent ratio, and substrate/catalyst ratio on the xylose conversion and furfural yield were investigated and 100% conversion of xylose and 74% yield of furfural was achieved within 5 h at $180^{\circ}C$. The bio-based heterogeneous acid catalysts could be used three times without any significant loss of activity. This greener protocol provides highly selective conversion of xylose to furfural as well as facile isolation of product and bio-based heterogeneous acid catalysts can alternate the environmentally-burdened mineral acids.

• Journal of Microbiology and Biotechnology
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• v.28 no.5
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• pp.732-738
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• 2018

Novel carbon-based solid acid catalysts were synthesized through a sustainable route from lipid-extracted microalgal residue of Dunaliella tertiolecta, for biodiesel production. Two carbon-based solid acid catalysts were prepared by surface modification of bio-char with sulfuric acid ($H_2SO_4$) and sulfuryl chloride ($SO_2Cl_2$), respectively. The treated catalysts were characterized and their catalytic activities were evaluated by esterification of oleic acid. The esterification catalytic activity of the $SO_2Cl_2$-treated bio-char was higher ($11.5mmol\;Prod.{\cdot}h^{-1}{\cdot}gCat.\;^{-1}$) than that of commercial catalyst silica-supported Nafion SAC-13 ($2.3mmol\;Prod.{\cdot}h^{-1}{\cdot}gCat.^{-1}$) and $H_2SO_4$-treated bio-char ($5.7mmol\;Prod.{\cdot}h^{-1}{\cdot}gCat.^{-1}$). Reusability of the catalysts was examined. The catalytic activity of the $SO_2Cl_2$-modified catalyst was sustained from the second run after the initial activity dropped after the first run and kept the same activity until the fifth run. It was higher than that of first-used Nafion. These experimental results demonstrate that catalysts from lipid-extracted algae have great potential for the economic and environment-friendly production of biodiesel.

• Proceedings of the PSK Conference
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• 2002.04a
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• pp.186.2-186.2
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• 2002