Reaction Kinetics of Gas–Solid Exchange Using Gas Phase Isotopic Oxygen Exchange
Reaction Kinetics of Gas–Solid Exchange Using Gas Phase Isotopic Oxygen Exchange
复制标题
利用气相同位素氧交换的气固交换反应动力学
DOI：
10.1021/acscatal.6b01462
复制
发表时间：
2016
期刊：
影响因子：
12.9
通讯作者：
E. Wachsman
中科院分区：
文献类型：
--
作者：
Yi;Christopher Pellegrinelli;E. Wachsman
基于两步反应机理，研究了混合离子电子导体（MIEC）La_（0.6）Sr_（0.4）Co_（0.2）Fe_（0.8）O_（3-x）（LSCF）和电子导体（La_（0.8）Sr_（0.2））Mn_（0.95）O_（3 ±x）（LSM）上的氧同位素交换过程. LSCF的催化活性高于LSM，这可能是由于LSCF具有较高的空位浓度所致。LSCF的表面交换的表观活化能低于从本体表征技术获得的值。LSM在不同温度下的扩散系数（D）与文献值有很大的偏差，并提出了一种替代的交换机制。快速传输途径归因于LSM在近表面区域的亚化学计量比。这些结果对提高氧还原反应的催化活性具有重要意义。
The oxygen transport kinetics of heterogeneous gas–solid exchange has been investigated on the basis of a two-step reaction mechanism, linking surface catalysis to solid-state self-diffusion, via gas phase isotopic oxygen exchange on the mixed ionic electronic conductor (MIEC) La0.6Sr0.4Co0.2Fe0.8O3–x (LSCF) and electronic conductor (La0.8Sr0.2)0.95MnO3±x (LSM). The catalytic activity of LSCF is higher than that of LSM toward the elementary step of oxygen dissociation, likely caused by a higher vacancy concentration. The apparent activation energy for surface exchange of LSCF is lower than values obtained from bulk characterization techniques. The diffusion coefficient (D) for LSM at different temperatures shows a huge deviation from literature values, and an alternate exchange mechanism has been proposed. The fast transport pathway is attributed to the substoichiometry of LSM in the near surface region. These results have significant implications for the improvement of the oxygen reduction reaction for t...