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Formation of Two-Dimensional Homologous Faults and Oxygen Electrocatalytic Activities in a Perovskite Nickelate.

Authors :
Bak J
Bae HB
Kim J
Oh J
Chung SY
Source :
Nano letters [Nano Lett] 2017 May 10; Vol. 17 (5), pp. 3126-3132. Date of Electronic Publication: 2017 Apr 11.
Publication Year :
2017

Abstract

Atomic-scale direct probing of active sites and subsequent elucidation of the structure-activity relationship are important issues involving oxide-based electrocatalysts to achieve better electrochemical conversion efficiency. By generating Ruddlesden-Popper (RP) two-dimensional homologous faults via simple control of the cation nonstoichiometry in LaNiO <subscript>3</subscript> thin films, we demonstrate that strong tetragonal distortion of [NiO <subscript>6</subscript> ] octahedra is induced by more than 20% elongation of Ni-O bonds in the faults. In addition to direct visualization of the elongation by scanning transmission electron microscopy, we identify that the distorted [NiO <subscript>6</subscript> ] octahedra in the faults show considerably higher electrocatalytic activities than other surface sites during the electrochemical oxygen evolution reaction. This unequivocal evidence of the octahedral distortion and its impact on electrocatalysis in LaNiO <subscript>3</subscript> suggests that the formation of RP-type faults can provide an efficient way to control the octahedral geometry and thereby remarkably enhance the oxygen catalytic performance of perovskite oxides.

Details

Language :
English
ISSN :
1530-6992
Volume :
17
Issue :
5
Database :
MEDLINE
Journal :
Nano letters
Publication Type :
Academic Journal
Accession number :
28394129
Full Text :
https://doi.org/10.1021/acs.nanolett.7b00561