Molecular Adsorption of H2O on TiO2 and TiO2:Y Surfaces

Nematov, Dilshod; Kholmurodov, Kholmirzo; Husenzoda, M. A.; Lyubchyk, A.; Burhonzoda, Amondulloi

doi:10.28991/hef-2022-03-02-07

Cited by 39 publications

(8 citation statements)

References 33 publications

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“…It is evident from previous studies that negative frequencies, which are less than 10 cm À1 , can be ignored. [59][60][61][62][63] Furthermore, the highest phonon mode of the 3D COT network is found to be around 2161 cm À1 at the centre (G) of the tetragonal Brillouin zone, which greatly exceeds the highest phonon mode frequency of graphite (E1600 cm À1 ). These results clearly affirm the dynamical stability of the 3D COT network.…”

Section: Structural Detailsmentioning

confidence: 91%

A nodal flexible-surface three-dimensional carbon network with potential applications as a lithium-ion battery anode material

Nulakani,

Bandyopadhyay,

Ali

2024

J. Mater. Chem. C

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Section: Structural Detailsmentioning

confidence: 91%

A nodal flexible-surface three-dimensional carbon network with potential applications as a lithium-ion battery anode material

Nulakani,

Bandyopadhyay,

Ali

2024

J. Mater. Chem. C

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“…However, little is known about the interaction of water with ZrO 2 surfaces at a fundamental level, which is mainly due to the lack of suitable samples. This is quite different for other oxide substrates [23][24][25]. Water is weakly adsorbed by many defect-free oxide surfaces in an ultra-high vacuum, then stripped at a temperature below room temperature.…”

Section: Introductionmentioning

confidence: 91%

A Detailed Comparative Analysis of the Structural Stability and Electron-Phonon Properties of ZrO2: Mechanisms of Water Adsorption on t-ZrO2 (101) and t-YSZ (101) Surfaces

Nematov,

Burhonzoda,

Kholmurodov

et al. 2023

Nanomaterials

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In this study, we considered the structural stability, electronic properties, and phonon dispersion of the cubic (c-ZrO2), tetragonal (t-ZrO2), and monoclinic (m-ZrO2) phases of ZrO2. We found that the monoclinic phase of zirconium dioxide is the most stable among the three phases in terms of total energy, lowest enthalpy, highest entropy, and other thermodynamic properties. The smallest negative modes were found for m-ZrO2. Our analysis of the electronic properties showed that during the m–t phase transformation of ZrO2, the Fermi level first shifts by 0.125 eV toward higher energies, and then decreases by 0.08 eV in the t–c cross-section. The band gaps for c-ZrO2, t-ZrO2, and m-ZrO2 are 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 onto the m-ZrO2 structure showed that the enthalpy of m-YSZ decreases linearly, which accompanies the further stabilization of monoclinic ZrO2 and an increase in its defectiveness. A doping-induced and concentration-dependent phase transition in ZrO2 under the influence of Y2O3 was discovered, due to which the position of the Fermi level changes and the energy gap decreases. It has been established that the main contribution to the formation of the conduction band is made by the p-states of electrons, not only for pure systems, but also those doped with Y2O3. The t-ZrO2 (101) and t-YSZ (101) surface models were selected as optimal surfaces for water adsorption based on a comparison of their surface energies. 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 results show that ab initio approaches are able to describe the mechanism of doping-induced phase transitions in (ZrO2+Y2O3)-like systems, based on which it can be assumed that DFT calculations can also flawlessly evaluate other physical and chemical properties of YSZ, which have not yet been studied quantum chemical research. 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.

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“…Understanding these features make it possible to tune the Fermi energies in the band structure for specific tasks in modern materials science and instrumentation. The results obtained will help to interpret some of the features of the electronic properties of ZrO2 and solid materials [32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48], and also complement the base of scientific work carried out in the field of using biocompatible zirconium dioxide crystals and ceramics for generating green energy. The data can be used in the design of moisture-to-electricity converters and the creation of solid oxide fuels.…”

Section: Stabilization Of M-zro2 and Electronic Properties Of Yszmentioning

confidence: 99%

Study on Structural Stability of ZrO<sub>2</sub> and YSZ: Doping-Induced Phase Transitions and Fermi Level Shift

Nematov,

Burkhonzoda,

Kholmurodov

et al. 2023

Preprint

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In this study, we considered the structural stability, electronic properties, and phonon dispersion of the cubic (c-ZrO2), tetragonal (t-ZrO2), and monoclinic (m-ZrO2) phases of ZrO2. We found that the monoclinic phase of zirconium dioxide is the most stable among the three phases in terms of total energy, lowest enthalpy, highest entropy, and other thermodynamic properties. The smallest negative modes were found for m-ZrO2. Our analysis of the electronic properties showed that during the m–t phase transformation of ZrO2, the Fermi level first shifts by 0.125 eV toward higher energies and then decreases by 0.08 eV in the t–c cross-section. The band gaps for c-ZrO2, t-ZrO2, and m-ZrO2 are 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 onto the m-ZrO2 structure showed that the enthalpy of m-YSZ decreases linearly, which accompanies further stabilization of monoclinic ZrO2 and an increase in its 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 but including those doped with Y2O3, the main contribution to the formation of the conduction band is made by the p-states of electrons. The t-ZrO2 (101) and t-YSZ (101) surface models were selected as optimal surfaces for water adsorption based on a comparison of their surface energies. 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 creating solid oxide fuel cells based on ZrO2.

show abstract

Molecular Adsorption of H2O on TiO2 and TiO2:Y Surfaces

Cited by 39 publications

References 33 publications

A nodal flexible-surface three-dimensional carbon network with potential applications as a lithium-ion battery anode material

A nodal flexible-surface three-dimensional carbon network with potential applications as a lithium-ion battery anode material

A Detailed Comparative Analysis of the Structural Stability and Electron-Phonon Properties of ZrO2: Mechanisms of Water Adsorption on t-ZrO2 (101) and t-YSZ (101) Surfaces

Study on Structural Stability of ZrO<sub>2</sub> and YSZ: Doping-Induced Phase Transitions and Fermi Level Shift

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