Strain Influence on the Oxygen Electrocatalysis of the (100)-Oriented Epitaxial La 2 NiO 4+δ Thin Films at Elevated Temperatures

Abstract
Ruddlesden-Popper materials such as La2NiO4+δ (LNO) have high activities for surface oxygen exchange kinetics promising for solid oxide fuel cells and oxygen permeation membranes. Here we report the synthesis of the (100)tetragonal-oriented epitaxial LNO thin films prepared by pulsed laser deposition. The surface oxygen exchange kinetics determined from electrochemical impedance spectroscopy (EIS) were found to increase with decreasing film thickness from 390 to 14 nm. No significant change of the surface chemistry with different film thicknesses was observed using ex situ auger electron spectroscopy (AES). Increasing volumetric strains in the LNO films at elevated temperatures determined from in situ high-resolution X-ray diffraction (HRXRD) were correlated with increasing surface exchange kinetics and decreasing film thickness. Volumetric strains may alter the formation energy of interstitial oxygen and influence on the surface oxygen exchange kinetics of the LNO films. © 2013 American Chemical Society.

Citation
Lee D, Grimaud A, Crumlin EJ, Mezghani K, Habib MA, et al. (2013) Strain Influence on the Oxygen Electrocatalysis of the (100)-Oriented Epitaxial La 2 NiO 4+δ Thin Films at Elevated Temperatures . The Journal of Physical Chemistry C 117: 18789–18795. Available: http://dx.doi.org/10.1021/jp404121p.

Acknowledgements
This work was supported in part by DOE (SISGR DESC0002633) and King Abdullah University of Science and Technology. The authors like to thank the King Fahd University of Petroleum and Minerals in Dharam, Saudi Arabia, for funding the research reported in this paper through the Center for Clean Water and Clean Energy at MIT and KFUPM. The PLD was conducted at the Center for Nanophase Materials Sciences, which is sponsored at Oak Ridge National Laboratory by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy.

Publisher
American Chemical Society (ACS)

Journal
The Journal of Physical Chemistry C

DOI
10.1021/jp404121p

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