Improved conductivity of NdFeO3 through partial substitution of Nd by Ca: a theoretical study

You Wang; Yun Wang; Wei Ren; Porun Liu; Huijun Zhao; Jun Chen; Jinxia Deng; Xianran Xing

doi:10.1039/C5CP03941J

Improved conductivity of NdFeO₃ through partial substitution of Nd by Ca: a theoretical study†

You Wang,^a Yun Wang,^b Wei Ren,^c Porun Liu,^b Huijun Zhao,*^b Jun Chen,^a Jinxia Deng^d and Xianran Xing*^a

* Corresponding authors

^a Department of Physical Chemistry, University of Science and Technology Beijing, Beijing 100083, China
E-mail: xing@ustb.edu.cn
Fax: +86 1062332525
Tel: +86 10 62332525

^b Centre for Clean Environment and Energy and Griffith School of Environment, Griffith University, Gold Coast Campus, QLD 4222, Australia
E-mail: h.zhao@griffith.edu.au
Fax: +61 7 55528067
Tel: +61 7 55528261

^c Department of Physics, International Center of Quantum and Molecular Structures, and Materials Genome Institute, Shanghai University, Shanghai 200444, China

^d Department of Chemistry, University of Science and Technology Beijing, Beijing 100083, China

Abstract

NdFeO₃ is an important candidate material for gas sensors and intermediate-temperature solid oxide fuel cells (IT-SOFC). However, its low conductivity prohibits its applications. In this study, we report that the doping of Ca by partially replacing Nd can effectively increase its conductivity. Through the electronic structure analysis of Nd_1−xCa_xFeO₃ (x = 0.00, 0.25, 0.50, 0.75 or 1.00) based on the first-principles density functional theory calculations, it is found that the hole states introduced by Ca substitution appear just above the Fermi level, which implies a high mobility of electrons/holes along the Fe–O–Fe bonding network. Specifically, it becomes easier to form O vacancies after Ca doping. Since the diffusion of O anions occurs through a vacancy hopping mechanism, the ion conductivity is also improved. These findings help us to gain an in-depth understanding of the colossally increased conductivity of Ca doped NdFeO₃ and turn the electronic conduction for its practical application in gas sensors and IT-SOFC.

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Article information

DOI: https://doi.org/10.1039/C5CP03941J
Article type: Paper
Submitted: 07 Jul 2015
Accepted: 28 Sep 2015
First published: 28 Sep 2015

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Phys. Chem. Chem. Phys., 2015,17, 29097-29102

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Improved conductivity of NdFeO₃ through partial substitution of Nd by Ca: a theoretical study

Y. Wang, Y. Wang, W. Ren, P. Liu, H. Zhao, J. Chen, J. Deng and X. Xing, Phys. Chem. Chem. Phys., 2015, 17, 29097 DOI: 10.1039/C5CP03941J

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