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Title: The partial reduction of clean and doped a-Fe2O3(0001) from first principles

Abstract

Fe surfaces have a wide range of applications due to the ability of Fe to be present in a number of different oxidation states, which can be further influenced by the presence of dopants that change the energetic and electronic surface properties. Thus, having an understanding of the elementary reduction processes of clean Fe oxide surfaces, and how dopants affect the energetics and electronics of such processes, is crucial to the science-guided design and optimization of said surfaces. In this work, we use density functional theory (DFT) to investigate the partial reduction of a-Fe2O3(0001) in the absence and presence of Pd and Pt dopants. In order to account for the strong on-site Coulombic interactions present in transition metal oxides, we used both the DFT?+?U method and 2006 Heyd-Scuseria-Ernzerhof functional and compare the results obtained from the different methods. We find that oxygen vacancies created in the clean a-Fe2O3(0001) surface prefer to diffuse into a subsurface layer, with the charge left behind from the first surface oxygen vacancy distributing between all of the near surface Fe atoms. The addition of Pd or Pt to the a-Fe2O3(0001) surface significantly decreases the energy required to create the first surface oxygen vacancy, suggesting themore » dopants intrinsically promote the reduction of a-Fe2O3(0001). Additionally, the presence of the dopants caused the charge left behind by the creation of the first surface oxygen vacancy to be localized on the dopant itself as well as the highest Fe atom. Overall, this work provides insight into the elementary energetic and electronic properties of the fully oxidized and partially reduced a-Fe2O3(0001) surface in the absence and presence of Pd and Pt dopants, which has potential implications for the design and optimization of doped Fe oxide surfaces.« less

Authors:
 [1];  [2];  [2]
  1. Washington State University
  2. WASHINGTON STATE UNIV
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1566283
Report Number(s):
PNNL-SA-147349
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Applied Catalysis. A, General
Additional Journal Information:
Journal Volume: 582
Country of Publication:
United States
Language:
English

Citation Formats

Hensley, Alyssa, Wang, Yong, and Mcewen, Jean Sabin. The partial reduction of clean and doped a-Fe2O3(0001) from first principles. United States: N. p., 2019. Web. doi:10.1016/j.apcata.2019.02.019.
Hensley, Alyssa, Wang, Yong, & Mcewen, Jean Sabin. The partial reduction of clean and doped a-Fe2O3(0001) from first principles. United States. doi:10.1016/j.apcata.2019.02.019.
Hensley, Alyssa, Wang, Yong, and Mcewen, Jean Sabin. Thu . "The partial reduction of clean and doped a-Fe2O3(0001) from first principles". United States. doi:10.1016/j.apcata.2019.02.019.
@article{osti_1566283,
title = {The partial reduction of clean and doped a-Fe2O3(0001) from first principles},
author = {Hensley, Alyssa and Wang, Yong and Mcewen, Jean Sabin},
abstractNote = {Fe surfaces have a wide range of applications due to the ability of Fe to be present in a number of different oxidation states, which can be further influenced by the presence of dopants that change the energetic and electronic surface properties. Thus, having an understanding of the elementary reduction processes of clean Fe oxide surfaces, and how dopants affect the energetics and electronics of such processes, is crucial to the science-guided design and optimization of said surfaces. In this work, we use density functional theory (DFT) to investigate the partial reduction of a-Fe2O3(0001) in the absence and presence of Pd and Pt dopants. In order to account for the strong on-site Coulombic interactions present in transition metal oxides, we used both the DFT?+?U method and 2006 Heyd-Scuseria-Ernzerhof functional and compare the results obtained from the different methods. We find that oxygen vacancies created in the clean a-Fe2O3(0001) surface prefer to diffuse into a subsurface layer, with the charge left behind from the first surface oxygen vacancy distributing between all of the near surface Fe atoms. The addition of Pd or Pt to the a-Fe2O3(0001) surface significantly decreases the energy required to create the first surface oxygen vacancy, suggesting the dopants intrinsically promote the reduction of a-Fe2O3(0001). Additionally, the presence of the dopants caused the charge left behind by the creation of the first surface oxygen vacancy to be localized on the dopant itself as well as the highest Fe atom. Overall, this work provides insight into the elementary energetic and electronic properties of the fully oxidized and partially reduced a-Fe2O3(0001) surface in the absence and presence of Pd and Pt dopants, which has potential implications for the design and optimization of doped Fe oxide surfaces.},
doi = {10.1016/j.apcata.2019.02.019},
journal = {Applied Catalysis. A, General},
number = ,
volume = 582,
place = {United States},
year = {2019},
month = {7}
}