Molecular and Dissociative Adsorption of H2O on ZrO2/YSZ Surfaces
Dilshod Nematov
Dilshod Nematov, S.U. Umarov Physical-Technical Institute of NAST, 734042 Tajikistan.
Manuscript received on 23 November 2023 | Revised Manuscript received on 07 October 2023 | Manuscript Accepted on 15 October 2023 | Manuscript published on 30 October 2023 | PP: 1-7 | Volume-11 Issue-10, October 2023 | Retrieval Number: 100.1/ijisme.D79271112423 | DOI: 10.35940/ijisme.D7927.10111023
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Abstract: The work involves first-principles calculations to study the mechanism of adsorption of water molecules on the surface of ZrO2 and their yttrium-stabilized structures (YSZ). Calculations of the electronic properties of ZrO2 showed that during the m-t phase transformation of ZrO2, the Fermi level first shifts by 0.125 eV towards the conduction band, and then in the t-c region goes down by 0.08 eV. In this case, the band gaps for c-ZrO2, t-ZrO2 and m-ZrO2, respectively, are 5.140 eV, 5.898 eV and 5.288 eV. Calculations to determine the surface energy showed that t-ZrO2 (101) and m-ZrO2 (111) have the most stable structure, on the basis of which it was first discovered that the surface energy is somehow inversely related to the value of the band gap, since as the band gap increases, the surface energy tends to decrease. 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. The obtained results complement the database of research works carried out in the field of the application of biocompatible zirconium dioxide crystals and ceramics in green energy generation, and can be used in designing humidity-to-electricity converters and in creating solid oxide fuel cells based on ZrO2.
Keywords: Zirconium Dioxide, Stability, Yttrium-Stabilized Zirconium Dioxide, Phase Transition, Fermi Level Shift, Water Adsorption on The Surface
Scope of the Article: Computer Science and Its Applications