- Synthesis and Catalytic Characteristics of Thermally Stable TiO2/Pt/SiO2 Hybrid Nanocatalysts
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A. Satyanarayana Reddy, Chan-Ho Jung, Sun-Mi Kim, Jung-Yeul Yun, Jeong-Young Park
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J Korean Powder Metall Inst. 2011;18(6):532-537.
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DOI: https://doi.org/10.4150/KPMI.2011.18.6.532
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- Thermally stable TiO_2/Pt/SiO_2 core-shell nanocatalyst has been synthesized by chemical processes. Citrated capped Pt nanoparticles were deposited on amine functionalized silica produced by Stober process. Ultrathin layer of titania was coated on Pt/SiO_2 for preventing sintering of the metal nanoparticles at high temperatures. Thermal stability of the metal-oxide hybrid catalyst was demonstrated heating the sample up to 600°C in air and by investigating the morphology and integrity of the structure by transmission electron spectroscopy. The surface analysis of the constituent elements was performed by X-ray photoemission spectroscopy. The catalytic activity of the hybrid catalysts was investigated by CO oxidation reaction with oxygen as a model reaction.
- Investigation of Catalytic Activity Through Controlling Its Size and Composition of RhPt Bimetallic Nanoparticles
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Jeong-Young Park, Sun-Mi Kim
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J Korean Powder Metall Inst. 2011;18(6):538-545.
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DOI: https://doi.org/10.4150/KPMI.2011.18.6.538
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- This study shows that catalytic activity of bimetallic RhPt nanoparticle arrays under CO oxidation can be tuned by varying the size and composition of nanoparticles. The tuning of size of RhPt nanoparticles was achieved by changing concentration of rhodium and platinum precursors in one-step polyol synthesis. Two-dimensional RhPt bimetallic nanoparticle arrays in different size and composition were prepared through Langmuir-Blodgett thin film technique. CO oxidation was carried out on these two-dimensional nanoparticle arrays, revealing higher activity on the smaller nanoparticles compared to the bigger nanoparticles. X-ray photoelectron spectroscopy (XPS) results indicate the preferential surface segregation of Rh compared to Pt on the smaller nanoparticles, which is consistent with the thermodynamic analysis. Because the catalytic activity is associated with differences in the rates of O_2 dissociative adsorption between Pt and Rh, this paper suppose that the surface segregation of Rh on the smaller bimetallic nanoparticles is responsible for the higher catalytic activity in CO oxidation. This result suggests a control mechanism of catalytic activity via synthetic approaches of colloid nanoparticles, with possible application in rational design of nanocatalysts.
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Citations to this article as recorded by  - Characteristics of Pt/C Nano-catalyst Synthesized by Arc Plasma Deposition
Hye-Sook Joo, Han-Shin Choi, Heon-Phil Ha, Do-Hyang Kim
Journal of Korean Powder Metallurgy Institute.2012; 19(1): 6. CrossRef
- Effect of Spark Plasma Sintering on the Materials Properties of Water Atomized Al-Zn-Mg Alloy
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Sun-Mi Kim, Taek-Soo Kim, Young-Do Kim, Jeong-Gon Kim
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J Korean Powder Metall Inst. 2009;16(1):63-67.
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DOI: https://doi.org/10.4150/KPMI.2009.16.1.063
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- In order to investigate the effect of rapid solidification on the microstructure and the mechanical properties of Al-Zn-Mg system alloys, water atomization was carried out, since the water atomization beared the highest solidification rate among the atomization processes. The as atomized alloy powders consisted of fine grains less than 4 µm in diameter, and the second particles were not detected on XRD. The microstructure as solidified was maintained even after the spark plasma sintering at the heating rate of 50 K/min. On the other hand, lower rate of 20 K/min induced a formation of MgZn_2 particles, resulting in strengthening of the matrix. The density was almost constant at the temperature above 698K. The sintering temperature above 698K had no effect on the strength of the sintered materials.
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Citations
Citations to this article as recorded by - Fabrication of Ultra Fine Grained Molybdenum and Mechanical Properties
Se-Hoon Kim, Young-Ik Seo, Dae-Gun Kim, Myung-Jin Suk, Young-Do Kim
Journal of Korean Powder Metallurgy Institute.2010; 17(3): 235. CrossRef
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