• 한국수소및신에너지학회논문집
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• 제26권6호
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• pp.516-523
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• 2015

Nickel based oxygen transfer materials supported on two different YSZs were tested to evaluate their performance in methane chemical-looping reforming. The oxygen transfer materials of YSZs were selected with different amount of the doped yittrium in the $ZrO_2$ structure. The yittrium of 8 mol% stabilized the zirconia oxide to a cubic structure compare to the 3 mol% doping, which is known to be a good for oxygen transfer. Various nickel amounts (16wt.%, 32wt.%, 48wt.%) were loaded on the selected supports. The nickel amount of 32% shows the optimized catalyst structure with good physical properties and reducibility from the XRD, BET and H2-TPR analysis, especially when the support of 8YSZ was used. From the methane chemical-looping reforming, hydrogen was produced by methane decomposition catalyzed by Ni on both YSZs. Comparing two YSZ supports of 3YSZ and 8YSZ during the cycling tests, the catalyst with 8YSZ (Ni 32%) exhibits not only the higher methane conversion and hydrogen production but also a faster reaction rate reaching to the stable point.

• 한국결정성장학회지
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• 제8권1호
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• pp.145-150
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• 1998

8mol%의 이트리아 안정화 지르코니아에 알루미나를 첨가하여 복합체를 제조하고 이때 알루미나 함량에 따른 전기 및 기계적 성질을 조사하였다. 3-점 곡강도와 파괴강도 값은 알루미나 함량이 20wt%까지 증가하였고, 복합체의 평균입자크기는 알루미나 첨가량이 증가할수록 감소하였다. 5wt%의 알루미나를 첨가하여 $1600^{\circ}C$, 2시간 유지하여 제조한 복합체의 3점 곡강도는 310MPa, 이때 파괴강도는 $7.8MPa\cdot\textrm m^{1/2}$이였다. 복합체의 전기 전도도 값은 알루미나 첨가량이 10wt%까지는 약간 증가하다가 그 이후로는 감소하였다. 알루미나 5wt% 첨가하여 $1600^{\circ}C$, 2시간 소결한 복합체의 전기 전도도는 0.4S/cm이였다.

• 한국세라믹학회지
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• 제50권6호
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• pp.423-428
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• 2013

Porous YSZ ceramics are fabricated using 3 mol% yittria-stabilized zirconia (3YSZ) and NiO with different particlesizes (0.6 and 7 ${\mu}m$). Nickel oxide (NiO) is added to the YSZ powder as a pore former with different amounts(40, 50, and 60 vol%) and at different sintering temperatures (1350 and $1400^{\circ}C$) are applied in order to evaluate the temperature effects on the pore and mechanical properties. Heat treatment is conducted after sintering at $700^{\circ}C$ in $H_2$ for the NiO reduction process; then, Ni is removed using a $HNO_3$ etchant solution. According to the NiO contentand sintering temperatures, 41-67% porous YSZ ceramic is obtained and the flexural strength increases, while the porosity decreases with an increasing sintering temperature. The optimum flexural strength ($136.5{\pm}13.4MPa$) and porosity (47%) for oxygen transport porous YSZ membrane can be obtained with 40 vol% of 7 ${\mu}m$ NiO particle at a sintering temperature of $1350^{\circ}C$.