Preprint Article Version 2 Preserved in Portico This version is not peer-reviewed

Study on Structural Stability of ZrO2 and YSZ: Doping-Induced Phase Transitions and Fermi Level Shift

Version 1 : Received: 7 August 2023 / Approved: 7 August 2023 / Online: 8 August 2023 (14:14:11 CEST)
Version 2 : Received: 7 September 2023 / Approved: 7 September 2023 / Online: 8 September 2023 (13:31:49 CEST)
Version 3 : Received: 10 September 2023 / Approved: 11 September 2023 / Online: 12 September 2023 (16:58:32 CEST)

A peer-reviewed article of this Preprint also exists.

D. D. Nematov, A. S. Burkhonzoda, Kh T. Kholmurodov, A. I. Lyubchyk, S. I. Lyubchyk, S. B. Lyubchyk. Study on Structural Stability of ZrO2 and YSZ: Doping-Induced Phase Transitions and Fermi Level Shift. Advanced Energy Conversion Materials [Internet]. 2023 Nov. 20 [cited 2023 Nov. 24];5(1):1-20. Available from: https://ojs.wiserpub.com/index.php/AECM/article/view/3686 D. D. Nematov, A. S. Burkhonzoda, Kh T. Kholmurodov, A. I. Lyubchyk, S. I. Lyubchyk, S. B. Lyubchyk. Study on Structural Stability of ZrO2 and YSZ: Doping-Induced Phase Transitions and Fermi Level Shift. Advanced Energy Conversion Materials [Internet]. 2023 Nov. 20 [cited 2023 Nov. 24];5(1):1-20. Available from: https://ojs.wiserpub.com/index.php/AECM/article/view/3686

Abstract

The paper considers the issues of structural stability, electronic properties, and phonon dispersion of the cubic, tetragonal, and monoclinic phases of ZrO2. It was found that the monoclinic phase of zirconium dioxide is the most stable among the other two phases in terms of total energy, lowest enthalpy, highest entropy, and other thermodynamic values. The smallest negative modes were found for m-ZrO2. An analysis of the electronic properties showed that during the m–t phase transformation of ZrO2, the Fermi level first shifts by 0.125 eV towards higher energies, and then decreases by 0.08 eV in the t–c cross section. The band gap for c-ZrO2, t-ZrO2, and m-ZrO2 is 5.140 eV, 5.898 eV, and 5.288 eV, respectively. Calculations based on the analysis of the influence of doping 3.23, 6.67, 10.35 and 16.15 mol. %Y2O3 on the m-ZrO2 structure showed that the enthalpy of m-YSZ decreases linearly, which accompanies further stabilization of monoclinic ZrO2 and an increase in their defectiveness. In this case, the position of the Fermi level changes abruptly, and the energy gap decreases. It has been established that not only for pure systems, including those doped with Y2O3, the main contribution to the formation of the conduction band is made by the p-states of electrons. An analysis of the mechanism of water adsorption on the surface of t-ZrO2 (101) and t-YSZ (101) showed that H2O on unstabilized t-ZrO2 (101) is adsorbed dissociatively with an energy of -1.22 eV, as well as by the method of molecular chemisorption with an energy of -0.69 eV and the formation of a hydrogen bond with a bond length of 1.01 Å. In the case of t-YSZ (101), water is molecularly adsorbed onto the surface with an energy of -1.84 eV. Dissociative adsorption of water occurs at an energy of -1.23 eV, near the yttrium atom.

Keywords

zirconia; stability; yttrium-stabilized zirconia; energy convertion; phase transition; Fermi level shift; water adsorption on the surface

Subject

Chemistry and Materials Science, Nanotechnology

Comments (1)

Comment 1
Received: 8 September 2023
Commenter: Dilshod Nematov
Commenter's Conflict of Interests: Author
Comment: Graphic abstract corrected, figure 13 changed, conclusion corrected
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