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Title: First-Principles Thermodynamics Study of Spinel MgAl 2 O 4 Surface Stability

Abstract

The surface stability of all possible terminations for three low-index (111, 110, 100) structures of the spinel MgAl2O4 has been studied using first-principles based thermodynamic approach. The surface Gibbs free energy results indicate that the 100_AlO2 termination is the most stable surface structure under ultra-high vacuum at T=1100 K regardless of Al-poor or Al-rich environment. With increasing oxygen pressure, the 111_O2(Al) termination becomes the most stable surface in the Al-rich environment. The oxygen vacancy formation is thermodynamically favorable over the 100_AlO2, 111_O2(Al) and the (111) structure with Mg/O connected terminations. On the basis of surface Gibbs free energies for both perfect and defective surface terminations, the 100_AlO2 and 111_O2(Al) are the most dominant surfaces in Al-rich environment under atmospheric condition. This is also consistent with our previously reported experimental observation. This work was supported by a Laboratory Directed Research and Development (LDRD) project of the Pacific Northwest National Laboratory (PNNL). The computing time was granted by the National Energy Research Scientific Computing Center (NERSC). Part of computing time was also granted by a scientific theme user proposal in the William R. Wiley Environmental Molecular Sciences Laboratory (EMSL), which is a U.S. Department of Energy national scientific user facility located atmore » PNNL in Richland, Washington.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org.:
USDOE
OSTI Identifier:
1328829
Report Number(s):
PNNL-SA-116841
Journal ID: ISSN 1932-7447; 48810
DOE Contract Number:
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Physical Chemistry. C; Journal Volume: 120; Journal Issue: 34
Country of Publication:
United States
Language:
English
Subject:
ab initio calculation; spinel materials; surface stability; Wulff construction; nanoparticle; Environmental Molecular Sciences Laboratory

Citation Formats

Cai, Qiuxia, Wang, Jian-guo, Wang, Yong, and Mei, Donghai. First-Principles Thermodynamics Study of Spinel MgAl 2 O 4 Surface Stability. United States: N. p., 2016. Web. doi:10.1021/acs.jpcc.6b02998.
Cai, Qiuxia, Wang, Jian-guo, Wang, Yong, & Mei, Donghai. First-Principles Thermodynamics Study of Spinel MgAl 2 O 4 Surface Stability. United States. doi:10.1021/acs.jpcc.6b02998.
Cai, Qiuxia, Wang, Jian-guo, Wang, Yong, and Mei, Donghai. Thu . "First-Principles Thermodynamics Study of Spinel MgAl 2 O 4 Surface Stability". United States. doi:10.1021/acs.jpcc.6b02998.
@article{osti_1328829,
title = {First-Principles Thermodynamics Study of Spinel MgAl 2 O 4 Surface Stability},
author = {Cai, Qiuxia and Wang, Jian-guo and Wang, Yong and Mei, Donghai},
abstractNote = {The surface stability of all possible terminations for three low-index (111, 110, 100) structures of the spinel MgAl2O4 has been studied using first-principles based thermodynamic approach. The surface Gibbs free energy results indicate that the 100_AlO2 termination is the most stable surface structure under ultra-high vacuum at T=1100 K regardless of Al-poor or Al-rich environment. With increasing oxygen pressure, the 111_O2(Al) termination becomes the most stable surface in the Al-rich environment. The oxygen vacancy formation is thermodynamically favorable over the 100_AlO2, 111_O2(Al) and the (111) structure with Mg/O connected terminations. On the basis of surface Gibbs free energies for both perfect and defective surface terminations, the 100_AlO2 and 111_O2(Al) are the most dominant surfaces in Al-rich environment under atmospheric condition. This is also consistent with our previously reported experimental observation. This work was supported by a Laboratory Directed Research and Development (LDRD) project of the Pacific Northwest National Laboratory (PNNL). The computing time was granted by the National Energy Research Scientific Computing Center (NERSC). Part of computing time was also granted by a scientific theme user proposal in the William R. Wiley Environmental Molecular Sciences Laboratory (EMSL), which is a U.S. Department of Energy national scientific user facility located at PNNL in Richland, Washington.},
doi = {10.1021/acs.jpcc.6b02998},
journal = {Journal of Physical Chemistry. C},
number = 34,
volume = 120,
place = {United States},
year = {Thu Sep 01 00:00:00 EDT 2016},
month = {Thu Sep 01 00:00:00 EDT 2016}
}
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