Wyniki wyszukiwania dla: Sang Heup Moon

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Performance of shape-controlled Pd nanoparticles in the selective hydrogenation of acetylene

Seok Ki Kim, Cheonghee Kim, Ji Hoon Lee, Jaeyoung Kim, więcej

Journal of Catalysis > 2013 > 306 > Complete > 146-154

Monodispersed Pd nanoparticles with controlled shapes, either cubes or spheres, were prepared and used as catalysts for acetylene hydrogenation at atmospheric pressure to investigate the effect of the Pd surface structure on the catalytic performance. Catalyst containing cubic Pd nanoparticles, whose surface consisted of the Pd(100) structure, exhibited higher acetylene conversion and ethylene selectivity...

artykuł

Properties of Pd/SiO2 catalyst doubly promoted with La oxide and Si for acetylene hydrogenation

Woo-Jae Kim, In Young Ahn, Jong-Hwa Lee, Sang Heup Moon

Catalysis Communications > 2012 > 24 > Complete > 52-55

Pd/SiO ₂ for acetylene hydrogenation was doubly promoted with La oxide and Si, the latter being selectively deposited on Pd instead of on SiO ₂ . La oxide promoted the ethylene selectivity of the catalyst due to its strong interaction with Pd after the catalyst had been reduced at high temperature, e.g., 500°C, and Si prevented the migration of La oxide in the catalyst when the reduced...

artykuł

Modified Pd catalysts for the selective hydrogenation of acetylene

Woo-Jae Kim, Sang Heup Moon

Catalysis Today > 2012 > 185 > 1 > 2-16

This article reviews our previous studies to develop high performance catalysts for acetylene hydrogenation. Ethylene selectivity of Pd catalysts in acetylene hydrogenation was improved by adding Si, metal oxides showing SMSI behavior, and either Ag or Cu as promoters. The promoter effect was further enhanced by maximizing the interactions between Pd and added promoters. Chemical vapor deposition...

artykuł

Preparation of CoMoS catalysts for hydrodesulfurization using methylacetoacetate as a chelating agent

Sang Il Lee, Ara Cho, Jae Hyun Koh, Sang Heup Moon

Korean Journal of Chemical Engineering > 2012 > 29 > 3 > 310-316

CoMoS/Al₂O₃ catalyst, which was prepared using Co(MeAA)₂·2H₂O as a new Co precursor, showed activity for hydrodesulfurization (HDS) higher than that of conventional catalysts, which were prepared using Co(NO₃)·6H₂O as a Co precursor and/or by adding ethylene-di-amine-tetra-acetic acid (EDTA) as a chelating agent. Catalyst of a similar activity was also obtained simply by impregnating a conventional...

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Performance of Ni-added Pd-Ag/Al₂O₃ catalysts in the selective hydrogenation of acetylene

Ji Hoon Lee, Seok Ki Kim, In Young Ahn, Woo-Jae Kim, więcej

Korean Journal of Chemical Engineering > 2012 > 29 > 2 > 169-172

Effects of Ni addition on the performance of Pd-Ag/Al₂O₃ catalysts in the selective hydrogenation of acetylene were investigated. Ni-added Pd-Ag catalysts showed higher conversions than Ni-free Pd-Ag catalyst under hydrogen-deficient reaction conditions, hydrogen/acetylene <2.0, due to the spillover of hydrogen from reduced Ni to Pd and the suppression of hydrogen penetration into the Pd bulk phase,...

artykuł

Synthesis of branched carbon nanotubes by carbonization of solid polyvinylidene fluoride fibers

Han-Ik Joh, Heung Yong Ha, Joghee Prabhuram, Seong Mu Jo, więcej

Carbon > 2011 > 49 > 13 > 4601-4603

Branched carbon nanotubes (b-CNTs) were synthesized by carbonization of polyvinylidene fluoride (PVDF) fibers containing a Pt catalyst. The solid fibrous polymer converted into carbon nanotubes with simultaneous growth of branches on the surface of the tubes during carbonization. The Pt particles were expected to decompose PVDF polymer inside the tubes into volatile carbonaceous species leaving a...

artykuł

Performance of Pd–Ag/Al2O3 catalysts prepared by the selective deposition of Ag onto Pd in acetylene hydrogenation

Ji Hoon Lee, Seok Ki Kim, In Young Ahn, Woo-Jae Kim, więcej

Catalysis Communications > 2011 > 12 > 13 > 1251-1254

The performance of Ag-promoted Pd/Al ₂ O ₃ catalysts, which were prepared by the selective deposition of Ag onto Pd using a surface redox (SR) method, during acetylene hydrogenation was compared with that of catalysts prepared by impregnation. The Pd surface was more effectively modified with Ag added by SR, even when small amounts of Ag were added. The catalyst prepared by SR showed...

artykuł

Performance of Cu-promoted Pd catalysts prepared by adding Cu using a surface redox method in acetylene hydrogenation

Seok Ki Kim, Ji Hoon Lee, In Young Ahn, Woo-Jae Kim, więcej

Applied Catalysis A, General > 2011 > 401 > 1-2 > 12-19

Cu-promoted Pd/Al ₂ O ₃ catalysts were prepared by selectively depositing Cu onto the Pd surface using a surface redox (SR) method, and their performance in the selective hydrogenation of acetylene was compared with that of Ag-promoted catalysts prepared by both the SR and the conventional impregnation method. The Cu-promoted catalysts prepared by SR showed higher ethylene selectivity...

artykuł

Chemical vapor deposition of highly dispersed Pt nanoparticles on multi-walled carbon nanotubes for use as fuel-cell electrodes

Heeyeon Kim, Sang Heup Moon

Carbon > 2011 > 49 > 4 > 1491-1501

Fuel-cell electrode catalysts with improved electrochemical properties have been prepared by dispersing Pt nanoparticles onto carbon nanotubes (CNT) using a chemical vapor deposition (CVD) method. (Trimethyl)methylcyclopentadienyl platinum (MeCpPtMe ₃ ) has been used as a Pt precursor in the CVD process and the CVD conditions have been optimized to disperse small Pt particles onto the CNT...

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Preparation of a CO-tolerant PtRuxSny/C electrocatalyst with an optimal Ru/Sn ratio by selective Sn-deposition on the surfaces of Pt and Ru

Jong Suk Yoo, Hyun Tae Kim, Han-Ik Joh, Heeyeon Kim, więcej

International Journal of Hydrogen Energy > 2011 > 36 > 3 > 1930-1938

A CO-tolerant PtRu _x Sn _y /C electrocatalyst, with an optimal x/y ratio of 0.8/0.2, was prepared by selectively depositing Sn on the metallic surface of PtRu _0.8 /C for use as the anode in a polymer electrolyte membrane fuel cell. The CO tolerance of the catalyst was greater when Sn was added by chemical vapor deposition (CVD) than by a conventional precipitation method because...

artykuł

Co promotion of sonochemically prepared MoS2/Al2O3 by impregnation with Co(acac)2·2H2O

Sang Il Lee, Ara Cho, Jae Hyun Koh, Seung Hoon Oh, więcej

Applied Catalysis B: Environmental > 2011 > 101 > 3-4 > 220-225

A highly active CoMoS/Al ₂ O ₃ catalyst was prepared by sonochemically synthesizing MoS ₂ crystallites dispersed on Al ₂ O ₃ and subsequently impregnating the prepared MoS ₂ /Al ₂ O ₃ with Co(acac) ₂ ·2H ₂ O. The formation of the catalytically active CoMoS phase was promoted when Co(acac) ₂ ·2H ₂ O, instead...

artykuł

Improved performance of Mo-V-Te-Nb-O_x catalysts prepared from a solution containing drying control chemical additives in propane oxidation to acrylic acid

Sang Seop Kum, Yoon Sik Park, Sang Heup Moon

Korean Journal of Chemical Engineering > 2011 > 28 > 6 > 1364-1371

Mo_1.0V_0.4Te_0.25Nb_0.24O_x catalyst was prepared by hydrothermal synthesis in a solution containing a drying control chemical additive (DCCA) such as propionic acid (PA) or formamide (FA). The performance of the prepared catalysts in propane oxidation for producing acrylic acid (AA) was improved because the catalyst showed an increase in both the activity and AA selectivity. The activity was increased...

artykuł

Properties of Pt-based electrocatalysts containing selectively deposited Sn as the anode for polymer electrolyte membrane fuel cells

Hyun Tae Kim, Jong Suk Yoo, Han-Ik Joh, Heeyeon Kim, więcej

International Journal of Hydrogen Energy > 2011 > 36 > 2 > 1606-1612

Sn-promoted Pt-based catalysts were prepared by the chemical vapor deposition (CVD) of Sn on commercial Pt/C and PtRu/C catalysts using Sn(CH ₃ ) ₄ as an Sn precursor. The prepared catalysts showed higher CO tolerance than those prepared by adding Sn using an impregnation (IMP) method. This result was obtained because Sn added by CVD was selectively deposited on the Pt and Ru surfaces,...

artykuł

Performance of WOx-added Mo–V–Te–Nb–O catalysts in the partial oxidation of propane to acrylic acid

Bu Young Jo, Sang Seop Kum, Sang Heup Moon

Applied Catalysis A, General > 2010 > 378 > 1 > 76-82

The performance of Mo _1.0 V _0.3 Te _0.23 Nb _0.23 O _x catalyst in the partial oxidation of propane to acrylic acid was improved when the catalyst was modified with an optimal amount of tungsten oxide (WO _x ), which was present largely in an amorphous phase. The added WO _x increased the catalyst activity by promoting the dehydration of the oxygenate...

artykuł

Improved performance of PtRu/C prepared by selective deposition of Ru on Pt as an anode for a polymer electrolyte membrane fuel cell

Hyun Tae Kim, Han-Ik Joh, Sang Heup Moon

Journal of Power Sources > 2010 > 195 > 5 > 1352-1358

Ru-promoted Pt/C catalysts with different Ru/Pt ratios are prepared by selective chemical vapour deposition (CVD) of Ru onto a Pt surface. The optimum PtRu/C (Ru/Pt=0.44) catalyst prepared using a CVD method shows improved performance as an anode for a polymer electrolyte membrane fuel cell in the presence of CO, as compared with a commercial PtRu/C (Ru/Pt=1) catalyst and a PtRu/C (Ru/Pt=1) catalyst...

artykuł

Activity and thermal stability of sonochemically synthesized MoS2 and Ni-promoted MoS2 catalysts

Ara Cho, Jae Hyun Koh, Sang Il Lee, Sang Heup Moon

Catalysis Today > 2010 > 149 > 1-2 > 47-51

Sonochemically synthesized MoS ₂ /Al ₂ O ₃ , which had a hydrodesulfurization (HDS) activity that was significantly greater than that of a catalyst prepared by impregnation, exhibited low thermal stability due to sintering of MoS ₂ crystallites at high temperatures. The thermal stability was improved when the catalyst was promoted with Ni. In this study, we compared...

artykuł

Development of Highly Active Co(Ni)Mo Catalysts for the Hydrodesulfurization of Dibenzothiophene Compounds

Ara Cho, Sang Heup Moon

Catalysis Surveys from Asia > 2010 > 14 > 2 > 64-74

Co- or Ni-promoted Mo sulfide catalysts were prepared by combining three methods, sonochemical synthesis of Mo sulfides, promoter addition by chemical vapor deposition (CVD), and fluorination of alumina support, to improve their performance in the hydrodesulfurization (HDS) process. Sonochemically synthesized Mo sulfides exhibited higher HDS activity, particularly for the hydrogenation (HYD) of dibenzothiophene...

artykuł

Preparation of Pt/C electrocatalysts using an incipient precipitation method

Han-Ik Joh, Sang Joon Seo, Hyun Tae Kim, Sang Heup Moon

Korean Journal of Chemical Engineering > 2010 > 27 > 1 > 45-48

Highly loaded and dispersed Pt/C catalysts, used as cathodic electrocatalysts in low temperature fuel cells, were prepared using a new method involving the slow addition of a Pt precursor to a solution containing dispersed carbon powder and a reducing agent. During this process, the added Pt precursor was reduced instantaneously into fine particles and adsorbed onto the carbon surface in the solution...

artykuł

A direct methanol fuel cell system to power a humanoid robot

Han-Ik Joh, Tae Jung Ha, Sang Youp Hwang, Jong-Ho Kim, więcej

Journal of Power Sources > 2010 > 195 > 1 > 293-298

In this study, a direct methanol fuel cell (DMFC) system, which is the first of its kind, has been developed to power a humanoid robot. The DMFC system consists of a stack, a balance of plant (BOP), a power management unit (PMU), and a back-up battery. The stack has 42 unit cells and is able to produce about 400W at 19.3V. The robot is 125cm tall, weighs 56kg, and consumes 210W during normal operation...

artykuł

Performance of Pd-promoted Mo–V–Te–Nb–O catalysts in the partial oxidation of propane to acrylic acid

Sang Seop Kum, Bu Young Jo, Sang Heup Moon

Applied Catalysis A, General > 2009 > 365 > 1 > 79-87

The performance of a Mo _1.0 V _0.3 Te _0.23 Nb _0.23 O _x catalyst in the partial oxidation of propane to obtain acrylic acid (AA) was improved when the catalyst was modified with an optimal amount of Pd oxide. The activity was increased due to an increase in the number of sites for the adsorption of propane and for the conversion of the adsorbed propane to propylene...

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