TY - JOUR
T1 - Unraveling the Negative Role of Oxygen-Vacancy Cluster in Ionic Conductivity in CeO2
T2 - Hybrid Functional Study
AU - Han, Xiaoping
AU - Amrane, Noureddine
AU - Zhang, Zongsheng
AU - Benkraouda, Maamar
N1 - Funding Information:
This work was supported by United Arab Emirates University through the University Program for Advanced Research (grants no. 31S109-UPAR and 31R109-Research Center-ECEER-9-2016). Part of computing time was provided by the North University of China.
Publisher Copyright:
© 2018 American Chemical Society.
PY - 2018/3/22
Y1 - 2018/3/22
N2 - Oxygen-vacancy formation and migration play a critical role in the high performance of CeO2 as a highly promising material for solving the environmental and energy-related issues. However, most of the associated works were directed toward the single or isolated oxygen vacancies. In this contribution, the formation and migration of an oxygen-vacancy cluster in CeO2 have been presented in detail using the Heyd-Scuseria-Ernzerhof hybrid functional method. The results demonstrate that oxygen vacancies exhibit a strong tendency to cluster in the 111 direction of CeO2. The detailed analyses of formation energy reveal the favorability for forming such a vacancy cluster under O-poor conditions. By means of the climbing-image nudged elastic band method and molecular dynamics simulations, the vacancy cluster is found to have a high kinetic stability and low mobility, thus becoming a challenge in achieving high ionic conductivity in CeO2. Attempts have been made to unravel the negative effect of vacancy clustering on ionic conductivity at an atomistic level, and possible means for avoiding or eliminating the vacancy clustering are proposed. The current work has implications for tailoring or optimizing the ionic conductivity in CeO2-based materials or devices for environmentally friendly applications.
AB - Oxygen-vacancy formation and migration play a critical role in the high performance of CeO2 as a highly promising material for solving the environmental and energy-related issues. However, most of the associated works were directed toward the single or isolated oxygen vacancies. In this contribution, the formation and migration of an oxygen-vacancy cluster in CeO2 have been presented in detail using the Heyd-Scuseria-Ernzerhof hybrid functional method. The results demonstrate that oxygen vacancies exhibit a strong tendency to cluster in the 111 direction of CeO2. The detailed analyses of formation energy reveal the favorability for forming such a vacancy cluster under O-poor conditions. By means of the climbing-image nudged elastic band method and molecular dynamics simulations, the vacancy cluster is found to have a high kinetic stability and low mobility, thus becoming a challenge in achieving high ionic conductivity in CeO2. Attempts have been made to unravel the negative effect of vacancy clustering on ionic conductivity at an atomistic level, and possible means for avoiding or eliminating the vacancy clustering are proposed. The current work has implications for tailoring or optimizing the ionic conductivity in CeO2-based materials or devices for environmentally friendly applications.
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U2 - 10.1021/acs.jpcc.7b11300
DO - 10.1021/acs.jpcc.7b11300
M3 - Article
AN - SCOPUS:85044483209
SN - 1932-7447
VL - 122
SP - 5871
EP - 5880
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
IS - 11
ER -