High Temperature Fabrication of Nanostructured Yttria-Stabilized-Zirconia (YSZ) Scaffolds by In Situ Carbon Templating Xerogels.
High Temperature Fabrication of Nanostructured Yttria-Stabilized-Zirconia (YSZ) Scaffolds by In Situ Carbon Templating Xerogels.
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通过原位碳模板干凝胶高温制造纳米结构氧化钇稳定氧化锆 (YSZ) 支架。
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发表时间：
2017
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通讯作者：
M. Gross
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作者：
S. Muhoza;M. Cottam;M. Gross
我们展示了一种高温制备多孔、纳米结构的氧化钇稳定氧化锆（YSZ, 8mol % ytria - 92mol % zirconia）支架的方法，其比表面积可调至80 m2·g-1。锆盐、钇盐和葡萄糖的水溶液与环氧丙烷（PO）混合形成凝胶。凝胶在环境条件下干燥形成干凝胶。干凝胶被压成颗粒，然后在氩气中烧结。在烧结过程中，形成YSZ陶瓷相，有机成分分解，留下无定形碳。原位形成的碳作为硬模板，在烧结温度下保持高表面积的YSZ纳米形态。碳随后在低温下通过空气氧化去除，从而产生多孔的纳米结构YSZ支架。通过改变凝胶合成中的葡萄糖浓度，可以系统地调节碳模板的浓度和最终支架的表面积。采用热重分析（TGA）对碳模板浓度进行定量，采用物理吸附法测定其比表面积和孔径分布，采用扫描电镜（SEM）对其形貌进行表征。用x射线衍射（XRD）测定了相纯度和晶粒尺寸。这种制造方法为实现基于陶瓷的电化学能量转换应用（例如固体氧化物燃料电池（SOFC）电极）的前所未有的支架表面积和纳米形态提供了一种新颖、灵活的平台。
We demonstrate a method for the high temperature fabrication of porous, nanostructured yttria-stabilized-zirconia (YSZ, 8 mol% yttria - 92 mol% zirconia) scaffolds with tunable specific surface areas up to 80 m2·g-1. An aqueous solution of a zirconium salt, yttrium salt, and glucose is mixed with propylene oxide (PO) to form a gel. The gel is dried under ambient conditions to form a xerogel. The xerogel is pressed into pellets and then sintered in an argon atmosphere. During sintering, a YSZ ceramic phase forms and the organic components decompose, leaving behind amorphous carbon. The carbon formed in situ serves as a hard template, preserving a high surface area YSZ nanomorphology at sintering temperature. The carbon is subsequently removed by oxidation in air at low temperature, resulting in a porous, nanostructured YSZ scaffold. The concentration of the carbon template and the final scaffold surface area can be systematically tuned by varying the glucose concentration in the gel synthesis. The carbon template concentration was quantified using thermogravimetric analysis (TGA), the surface area and pore size distribution was determined by physical adsorption measurements, and the morphology was characterized using scanning electron microscopy (SEM). Phase purity and crystallite size was determined using X-ray diffraction (XRD). This fabrication approach provides a novel, flexible platform for realizing unprecedented scaffold surface areas and nanomorphologies for ceramic-based electrochemical energy conversion applications, e.g. solid oxide fuel cell (SOFC) electrodes.