Cerium–terbium mixed oxides as potential materials for anodes in solid oxide fuel cells
Cerium–terbium mixed oxides as potential materials for anodes in solid oxide fuel cells
复制标题
DOI：
10.1016/j.jpowsour.2005.02.079
复制
发表时间：
2005-10
影响因子：
9.2
通讯作者：
A. Martínez-Arias;A. Hungría;M. Fernández-García;A. Iglesias-Juez;J. Conesa;G. C. Mather;G. Munuera
中科院分区：
文献类型：
--
作者：
A. Martínez-Arias;A. Hungría;M. Fernández-García;A. Iglesias-Juez;J. Conesa;G. C. Mather;G. Munuera
采用微乳液技术制备了高度均匀的（Ce，Tb）氧化物，并利用X射线衍射、高分辨透射电子显微镜、X射线光电子能谱和吸收谱（XANES）以及交流阻抗谱研究了它们高温煅烧后的结构和电子状态。添加Tb在高温煅烧（高达1100°C）期间显著稳定（与纯二氧化铈相比）比表面积和小粒度;在这些高温下不发生相分解，类似于当用Zr进行二氧化铈的稳定化时发生的相分解，并且混合氧化物始终保持均匀。因此，当用作SOFC阳极的组分时，向二氧化铈中添加Tb可能是有益的。TEM数据表明氧化物颗粒的重塑，并提供高温处理后的晶体超结构的证据，而XPS和XANES揭示了增加的Tb 4 +/Tb 3+的比例（对于一个给定的预处理）与Tb/Ce的比例; Ce似乎是较少还原为Ce 3+在Tb的存在下。CT样品的总电导率下H2介导的电子传输（可能只涉及铈），是低于钆掺杂的氧化铈（GCO）;在空气中的电导率高于GCO，特别是在低温下，它是可能的，在这种情况下，P型运输机制占主导地位。
Highly homogeneous (Ce,Tb) oxides are prepared by a microemulsion technique, and their structural and electronic state after high temperature calcination is examined with X-ray diffraction, high resolution transmission electron microscopy, X-ray photoelectron and absorption (XANES) spectroscopies and impedance spectroscopy measurements. Addition of Tb stabilizes significantly (in comparison to pure ceria) specific surface area and small particles sizes during high temperature calcination (up to 1100°C); phase decomposition at these high temperatures, similar to that occurring when stabilization of ceria is carried out with Zr, does not occur, and the mixed oxide remains homogeneous throughout. Tb addition to ceria may thus be beneficial when used as a component of SOFC anodes. TEM data indicate reshaping of oxide particles and provide evidence of crystal superstructures after high temperature treatments, while XPS and XANES reveal an increase in the Tb4+/Tb3+ratio (for a given pretreatment) with the Tb/Ce ratio; Ce seems to be less reducible to Ce3+in the presence of Tb. Total electrical conductivity of CT samples under H2is mediated by electron transport (involving probably only Ce) and is lower than in gadolinia-doped ceria (GCO); in air conductivity is higher than for GCO, particularly at low temperatures, and it is probable that a p-type transport mechanism predominates in this case.