Influence of Heterointerfaces on the Kinetics of Oxygen Surface Exchange on Epitaxial La1.85Sr0.15CuO4 Thin Films

Applied Sciences

JongK. Keum¹  Dongkyu Lee²  Gene Yang²  Changhee Sohn³  SoYeun Kim³ 

[1] Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Neutron Scattering Division, Oak Ridge, TN 37830, USA;Department of Mechanical Engineering, University of South Carolina, Columbia, SC 29208, USA;Department of Physics, Ulsan National Institute of Science and Technology, Ulsan 44919, Korea;

关键词: solid oxide fuel cells;    cathodes;    oxygen reductions reaction;    oxygen surface exchange kinetics;    electrical conductivity relaxation;    oxide thin films;   

DOI  :  10.3390/app11093778

来源: DOAJ

【 摘 要 】

Considerable attention has been directed to understanding the influence of heterointerfaces between Ruddlesden–Popper (RP) phases and ABO₃ perovskites on the kinetics of oxygen electrocatalysis at elevated temperatures. Here, we report the effect of heterointerfaces on the oxygen surface exchange kinetics by employing heteroepitaxial oxide thin films formed by decorating LaNiO₃ (LNO) on La_1.85Sr_0.15CuO₄ (LSCO) thin films. Regardless of LNO decoration, tensile in-plane strain on LSCO films does not change. The oxygen surface exchange coefficients (k_chem) of LSCO films extracted from electrical conductivity relaxation curves significantly increase with partial decorations of LNO, whereas full LNO coverage leads to the reduction in the k_chem of LSCO films. The activation energy for oxygen exchange in LSCO films significantly decreases with partial LNO decorations in contrast with the full coverage of LNO. Optical spectroscopy reveals the increased oxygen vacancies in the partially covered LSCO films relative to the undecorated LSCO film. We attribute the enhanced oxygen surface exchange kinetics of LSCO to the increased oxygen vacancies by creating the heterointerface between LSCO and LNO.

【 授权许可】

Unknown