• Journal of Ceramic Processing Research
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• 제21권3호
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• pp.296-301
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• 2020

Ni as a catalyst for steam methane reforming (SMR) was deposited on a porous Al₂O₃ support using a hydrothermal-infiltration method. The SMR performance of Ni/Al₂O₃ composites was strongly affected by the microstructural change of the support according to the firing temperature. While there was no significant change up to 800 ℃, significant grain growth and large interfacial necking occurred after firing at 1,200 ℃, resulting in a significant increase in both porosity and pore size. The Al₂O₃ support with a large pore size and broad pore size distribution could load a relatively larger amount of Ni catalyst during the hydrothermal-infiltration process and facilitate the diffusion of reaction gases. Therefore, the Ni/Al₂O₃ composite with the support fired at 1,200 ℃ exhibited the best SMR performance. Meanwhile, Ni catalysts were distributed evenly throughout the porous support in the Ni/Al₂O₃ composite prepared by the hydrothermal-infiltration method compared to that prepared by the conventional infiltration method. Therefore, the Ni/Al₂O₃ composite prepared by the hydrothermal-infiltration method exhibited much better SMR performance. Moreover, no significant performance degradation was observed at 600 ℃ for 100 h.

• 한국재료학회지
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• 제22권7호
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• pp.362-367
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• 2012

Magnetite nanoparticles(NPs) have been the subject of much interest by researchers owing to their potential use as magnetic carriers in drug targeting and as a tumor treatment in cases of hyperthermia. However, magnetite nanoparticles with 10 nm in diameter easily aggregate and thus create large secondary particles. To disperse magnetite nanoparticles, this study proposes the infiltration of magnetite nanoparticles into hybrid silica aerogels. The feasible dispersion of magnetite is necessary to target tumor cells and to treat hyperthermia. Magnetite NPs have been synthesized by coprecipitation, hydrothermal and thermal decomposition methods. In particular, monodisperse magnetite NPs are known to be produced by the thermal decomposition of iron oleate. In this study, we thermally decomposed iron acetylacetonate in the presence of oleic acid, oleylamine and 1,2 hexadecanediol. We also attempted to disperse magnetite NPs within a mesoporous aerogels. Methyltriethoxysilicate(MTEOS)-based hybrid silica aerogels were synthesized by a supercritical drying method. To incorporate the magnetite nanoparticles into the hybrid aerogels, we devised two methods: adding the synthesized aerogel into a magnetite precursor solution followed by nucleation and crystal growth within the pores of the aerogels, and the infiltration of magnetite nanoparticles synthesized beforehand into aerogel matrices by immersing the aerogels in a magnetite nanoparticle colloid solution. An analysis using a vibrating sample magnetometer showed that approximately 20% of the magnetite nanoparticles were well dispersed in the aerogels. The composite samples showed that heating under an inductive magnetic field to a temperature of $45^{\circ}C$ is possible.