Imperial College London
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ProfessorAndrewHorsfield

Faculty of Engineering, Department of Materials

Professor of Theory and Simulation of Materials
 
 
 
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Contact

 

+44 (0)20 7594 6753a.horsfield

 
 
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Location

 

Bessemer B331Royal School of MinesSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Horsfield:2015:10.1039/C5TA03759J,
author = {Horsfield, AP and Wu, J and skinner, S and pramana, S and Kilner, JA},
doi = {10.1039/C5TA03759J},
journal = {Journal of Materials Chemistry A},
pages = {23760--23767},
title = {Why Ni is absent from the surface of La2NiO4+delta?},
url = {http://dx.doi.org/10.1039/C5TA03759J},
volume = {3},
year = {2015}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - La2NiO4+δ (LNO214) is a potential intermediate temperature solid oxide fuel cell (IT-SOFC) cathode material which belongs to the Ruddlesden–Popper (RP) structure series An+1BnO3n+1. There is interest in this material as it offers a way to avoid Sr segregation and associated degradation, as LNO214 can take in oxygen interstitials and become catalytically active without A-site doping. While the bulk ionic conduction mechanisms are well studied, its surface structure and chemistry are still a matter of debate. Recent experimental studies (both with and without dopants) reveal that it has a La-terminated surface and a highly Ni deficient surface layer. These results disagree with previous computer simulations, and undermine the conventional explanation for the oxygen reduction process at the surface. In this work we evaluate the thermodynamic stability of La2NiO4+δ at IT-SOFC operation temperatures. We find that the decomposition of La2NiO4+δ to produce La2O3 and higher order RP phases is indeed thermodynamically favourable. A hypothesis for the formation mechanism of the La-terminated and Ni deficient surface based on partial decomposition and surface passivation is proposed and evaluated.
AU  - Horsfield,AP
AU  - Wu,J
AU  - skinner,S
AU  - pramana,S
AU  - Kilner,JA
DO  - 10.1039/C5TA03759J
EP  - 23767
PY  - 2015///
SN  - 2050-7488
SP  - 23760
TI  - Why Ni is absent from the surface of La2NiO4+delta?
T2  - Journal of Materials Chemistry A
UR  - http://dx.doi.org/10.1039/C5TA03759J
UR  - https://pubs.rsc.org/en/content/articlelanding/2015/TA/C5TA03759J
UR  - http://hdl.handle.net/10044/1/28495
VL  - 3
ER  -
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