Praseodymium-cerium oxide thin film cathodes: Study of oxygen reduction reaction kinetics
Praseodymium-cerium oxide thin film cathodes: Study of oxygen reduction reaction kinetics
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DOI：
10.1007/s10832-011-9678-z
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发表时间：
2012-02-01
影响因子：
1.7
通讯作者：
Tuller, Harry L.
中科院分区：
文献类型：
--
作者：
Chen, Di;Bishop, Sean R.;Tuller, Harry L.
氧化镨-铈（PrxCe 1-xO 2-delta; PCO）是一种潜在的三效催化剂储氧材料和固体氧化物燃料电池（SOFC）阴极，即使在氧化（例如空气）条件下也表现出令人惊讶的高水平的氧非化学计量比，导致混合离子电子电导率（MIEC）。在这项研究中，我们研究了致密的PCO薄膜的氧化还原动力学使用阻抗谱，x = 0.01，0.10和0.20，在550至670 A摄氏度的温度范围内，和氧分压范围为10（-4）至1大气压O-2。观察到的电极阻抗是独立的电极厚度和电极面积成反比，指向表面交换，而不是体扩散限制动力学。对于x = 0.1和x = 0.2 PCO，发现大的电极电容（10（-2）F）与预期的化学计量的大的电化学诱导变化一致。PCO膜显示出令人惊讶的快速氧交换动力学，与其他高性能SOFC阴极材料相当，由此计算出表面交换系数k（q）的值。该研究证实了PCO作为与基于氧化锆和二氧化铈的固体氧化物电解质相容的模型MIEC阴极材料的适合性。
Praseodymium-Cerium Oxide (PrxCe1-xO2-delta; PCO), a potential three way catalyst oxygen storage material and solid oxide fuel cell (SOFC) cathode, exhibits surprisingly high levels of oxygen nonstoichiometry, even under oxidizing (e.g. air) conditions, resulting in mixed ionic electronic conductivity (MIEC). In this study we examine the redox kinetics of dense PCO thin films using impedance spectroscopy, for x = 0.01, 0.10 and 0.20, over the temperature range of 550 to 670A degrees C, and the oxygen partial pressure range of 10(-4) to 1 atm O-2. The electrode impedance was observed to be independent of electrode thickness and inversely proportional to electrode area, pointing to surface exchange rather than bulk diffusion limited kinetics. The large electrode capacitance (10(-2)F) was found to be consistent with an expected large electrochemically induced change in stoichiometry for x = 0.1 and x = 0.2 PCO. The PCO films showed surprisingly rapid oxygen exchange kinetics, comparable to other high performance SOFC cathode materials, from which values for the surface exchange coefficient, k (q) , were calculated. This study confirms the suitability of PCO as a model MIEC cathode material compatible with both zirconia and ceria based solid oxide electrolytes.