### Abstract

This contribution investigates the effect of the addition of the Hubbard U parameter on the electronic structural and mechanical properties of cubic (C-type) lanthanide sesquioxides (Ln
_{2}
O
_{3}
). Calculated Bader's charges confirm the ionic character of Ln–O bonds in the C-type Ln
_{2}
O
_{3}
. Estimated structural parameters (i.e., lattice constants) coincide with analogous experimental values. The calculated band gaps energies at the U
_{eff}
of 5 eV for these compounds exhibit a non-metallic character and U
_{eff}
of 6.5 eV reproduces the analogous experimental band gap of cerium sesquioxide Ce
_{2}
O
_{3}
. We have thoroughly investigated the effect of the O/Ce ratios and the effect of hafnium (Hf) and zirconium (Zr) dopants on the reduction energies of CeO
_{x}
configurations. Our analysis for the reduction energy of CeO
_{2}
, over a wide range of temperatures displays that, shuffling between the two +4 and +3 oxidation states of Ce exhibit a temperature-independent behaviour. Higher O/Ce ratios necessitate lower reduction energies. Our results on Ce–Hf–Zr–O alloys are in reasonable agreements with analogous fitted values pertinent to lowering reduction energies and shrinkage in lattice parameters when contrasted with pure CeO
_{2}
. Structural analysis reveals that Hf and Zr atoms in the solid solution are shifted towards the nearest vacancies upon reduction. It is hoped that values provided herein to shed an atomic-base insight into the reduction/oxidation thermodynamics of increasingly deployed catalysts for environmental applications.

Original language | English |
---|---|

Pages (from-to) | 37-48 |

Number of pages | 12 |

Journal | Thin Solid Films |

Volume | 653 |

DOIs | |

Publication status | Published - 1 May 2018 |

Externally published | Yes |

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### Cite this

*Thin Solid Films*,

*653*, 37-48. https://doi.org/10.1016/j.tsf.2018.01.063

}

*Thin Solid Films*, vol. 653, pp. 37-48. https://doi.org/10.1016/j.tsf.2018.01.063

**Thermo-mechanical properties of cubic lanthanide oxides.** / Miran, Hussein A.; Altarawneh, Mohammednoor; Widjaja, Hantarto; Jaf, Zainab N.; Mahbubur Rahman, M.; Veder, Jean Pierre; Dlugogorski, Bogdan Z.; Jiang, Zhong Tao.

Research output: Contribution to journal › Article › Research › peer-review

TY - JOUR

T1 - Thermo-mechanical properties of cubic lanthanide oxides

AU - Miran, Hussein A.

AU - Altarawneh, Mohammednoor

AU - Widjaja, Hantarto

AU - Jaf, Zainab N.

AU - Mahbubur Rahman, M.

AU - Veder, Jean Pierre

AU - Dlugogorski, Bogdan Z.

AU - Jiang, Zhong Tao

PY - 2018/5/1

Y1 - 2018/5/1

N2 - This contribution investigates the effect of the addition of the Hubbard U parameter on the electronic structural and mechanical properties of cubic (C-type) lanthanide sesquioxides (Ln 2 O 3 ). Calculated Bader's charges confirm the ionic character of Ln–O bonds in the C-type Ln 2 O 3 . Estimated structural parameters (i.e., lattice constants) coincide with analogous experimental values. The calculated band gaps energies at the U eff of 5 eV for these compounds exhibit a non-metallic character and U eff of 6.5 eV reproduces the analogous experimental band gap of cerium sesquioxide Ce 2 O 3 . We have thoroughly investigated the effect of the O/Ce ratios and the effect of hafnium (Hf) and zirconium (Zr) dopants on the reduction energies of CeO x configurations. Our analysis for the reduction energy of CeO 2 , over a wide range of temperatures displays that, shuffling between the two +4 and +3 oxidation states of Ce exhibit a temperature-independent behaviour. Higher O/Ce ratios necessitate lower reduction energies. Our results on Ce–Hf–Zr–O alloys are in reasonable agreements with analogous fitted values pertinent to lowering reduction energies and shrinkage in lattice parameters when contrasted with pure CeO 2 . Structural analysis reveals that Hf and Zr atoms in the solid solution are shifted towards the nearest vacancies upon reduction. It is hoped that values provided herein to shed an atomic-base insight into the reduction/oxidation thermodynamics of increasingly deployed catalysts for environmental applications.

AB - This contribution investigates the effect of the addition of the Hubbard U parameter on the electronic structural and mechanical properties of cubic (C-type) lanthanide sesquioxides (Ln 2 O 3 ). Calculated Bader's charges confirm the ionic character of Ln–O bonds in the C-type Ln 2 O 3 . Estimated structural parameters (i.e., lattice constants) coincide with analogous experimental values. The calculated band gaps energies at the U eff of 5 eV for these compounds exhibit a non-metallic character and U eff of 6.5 eV reproduces the analogous experimental band gap of cerium sesquioxide Ce 2 O 3 . We have thoroughly investigated the effect of the O/Ce ratios and the effect of hafnium (Hf) and zirconium (Zr) dopants on the reduction energies of CeO x configurations. Our analysis for the reduction energy of CeO 2 , over a wide range of temperatures displays that, shuffling between the two +4 and +3 oxidation states of Ce exhibit a temperature-independent behaviour. Higher O/Ce ratios necessitate lower reduction energies. Our results on Ce–Hf–Zr–O alloys are in reasonable agreements with analogous fitted values pertinent to lowering reduction energies and shrinkage in lattice parameters when contrasted with pure CeO 2 . Structural analysis reveals that Hf and Zr atoms in the solid solution are shifted towards the nearest vacancies upon reduction. It is hoped that values provided herein to shed an atomic-base insight into the reduction/oxidation thermodynamics of increasingly deployed catalysts for environmental applications.

KW - Density functional theory

KW - Lanthanum oxide

KW - Mechanical stability

KW - Reduction energy

UR - http://www.scopus.com/inward/record.url?scp=85043337311&partnerID=8YFLogxK

U2 - 10.1016/j.tsf.2018.01.063

DO - 10.1016/j.tsf.2018.01.063

M3 - Article

VL - 653

SP - 37

EP - 48

JO - Thin Solid Films

JF - Thin Solid Films

SN - 0040-6090

ER -