ONIOM study of dissociated hydrogen and water on ZnO surface

Martins, João B. L.; Taft, Carlton A.; Longo, Elson; Castro, Elton Anderson Santos de; Cunha, Wiliam Ferreira da; Politi, José R. S.; Gargano, Ricardo

doi:10.1002/qua.24147

Cited by 10 publications

(13 citation statements)

References 46 publications

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“…An HF study using a (ZnO) 6 cluster indicated that H 2 dissociation took place on both the Zn and O sites, with a preference on the two-coordinated O sites . A recent reactive molecular dynamics (RMD) simulation of water dissociation on stepped ZnO surfaces shows that the surface H 2 O molecules can dissociate into surface hydroxyls, in agreement with previous reports. ,− …”

Section: Introductionsupporting

confidence: 88%

ReaxFF Molecular Dynamic Simulations of ZnO Nanocluster and Films in H₂ Atmosphere

Zhang

Cheng

et al. 2017

J. Phys. Chem. C

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Reactive molecular dynamics simulations were performed to explore the structural evolution of a ZnO nanocluster and (0001) and (101̅0) surfaces under a H2 atmosphere at different temperatures. The mechanisms of H2 dissociation and water formation were analyzed. Our simulations reveal that there are two pathways for H2 dissociation and three routes for water formation on the surfaces. The nanocluster is more active for H2 dissociation and water formation than the two surfaces. The gas–solid interactions lead to outward displacement of the substrate O atoms. While the O-terminated surface of the (0001) facet is active for H2 dissociation and water formation, the Zn-terminated one is inactive for the dissociation. Unlike the (0001) surface which is more easily reduced, the (101̅0) surface is readily hydroxylated. Water formation and desorption results in surface oxygen depletion and Zn aggregation which lead to surface metallization, in accordance with the experimental observations. Our simulations show that Zn sites are not active for H2 dissociation. By fitting the obtained rate constants at different temperatures, we estimated the activation energy of the H2 dissociation over ZnO cluster to be 4.06 kcal/mol, in very good agreement with the experimental result of 5.0 kcal/mol.

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Section: Introductionsupporting

confidence: 88%

ReaxFF Molecular Dynamic Simulations of ZnO Nanocluster and Films in H₂ Atmosphere

Zhang

Cheng

et al. 2017

J. Phys. Chem. C

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“…61,106 The rest of adsorption conformations lay 20 kJ mol -1 or higher in energy. As happened when dissociating H 2 , the surface atoms recover a near-tetrahedral geometry, 100 in which ZnO surface units elongate their bonds by 18.7 pm, and surface rumpling essentially vanishes.…”

Section: Full Analysis Of H/oh/h 2 O Species On Polar and Nonpolar Surfacesmentioning

confidence: 99%

“…99 When having both species, the overall adsorption strength is enhanced, due to the bulk near-tetrahedral coordination geometry recovery. 100 The simulated IR spectra shown in Figure 3 displays two peaks at 1797 and 3601 cm -1 belonging to surface Zn-H or O s -H stretching vibrations, respectively. These would correspond to the observed peaks by Wang et al at 1613 and 3670 cm -1 , respectively.…”

Section: Indeed Previous Experiments Combining Leed and He-atom Scattering (Has) Experimentsmentioning

confidence: 99%

Hydroxyl Identification on ZnO by Infrared Spectroscopies: Theory and Experiments

2014

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Here we present a thorough density functional study combining experiments on ZnO nanostructures aimed at the identification, by means of Infrared (IR) spectroscopies, of hydroxyl and hydride species formed on most stable low-index Miller surfaces of würtzite ZnO; namely, Zn-and O-terminated (0001) and (0001) polar surfaces, and nonpolar (1010) and (1120) surfaces. The Perdew-Burke-Ernzerhof functional was employed on the periodic slab calculations, and all possible H and OH adsorption modes were studied at medium and full coverage, while IR spectra were simulated for most favourable situations. This information was used to model the most likely surface arrangements when exposed to either H 2 or H 2 O. IR experiments on ZnO surfaces and nanoparticles are discussed based on the calculated adsorption energy values and simulated IR spectra. The study emphasizes the detailed assignment of OH moieties with the help of IR and their interpretation as fingerprints of surface morphology, allowing for a consistent interpretation of water adlayers stability and their corresponding vibrational fingerprints as a function of coverage, low-index Miller surface, and hydrogen source.

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“…Wander and Harisson used B3LYP hybrid functional calculations to study the geometry and electronic structure of (only) the heterolytically terminated 2 ML-both configuration. Martins et al used high-level CCSD calculations to compare the energetics of the 2 ML-both and molecular H 2 adsorption configurations on small ZnO cluster models.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamics of Hydrogen Adsorption and Incorporation at the ZnO(101̅0) Surface

Wilson

Barnard

2015

J. Phys. Chem. C

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Hydrogen, as a surface adsorbate and a bulk impurity, plays an important role in determining the electronic and catalytic properties of zinc oxide, but the nature of the interaction between these two species remains poorly understood. In this work we study the thermodynamics of hydrogen adsorption on zinc oxide’s (100)) surface. We find that the adsorption of hydrogen on the oxygen sites only, as observed in several previous experiments, is metastable and consider the thermodynamics of exchange of hydrogen between surface and bulk as an explanatory mechanism. We propose that the hydrogen termination of zinc oxide at room temperature is strongly dependent on the hydrogen concentration of the interior and thus that surface reactions involving hydrogen may proceed in an unreliable way depending on the history of the sample, particularly for ZnO in nanostructures.

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ONIOM study of dissociated hydrogen and water on ZnO surface

Cited by 10 publications

References 46 publications

ReaxFF Molecular Dynamic Simulations of ZnO Nanocluster and Films in H₂ Atmosphere

ReaxFF Molecular Dynamic Simulations of ZnO Nanocluster and Films in H₂ Atmosphere

Hydroxyl Identification on ZnO by Infrared Spectroscopies: Theory and Experiments

Thermodynamics of Hydrogen Adsorption and Incorporation at the ZnO(101̅0) Surface

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ONIOM study of dissociated hydrogen and water on ZnO surface

Cited by 10 publications

References 46 publications

ReaxFF Molecular Dynamic Simulations of ZnO Nanocluster and Films in H2 Atmosphere

ReaxFF Molecular Dynamic Simulations of ZnO Nanocluster and Films in H2 Atmosphere

Hydroxyl Identification on ZnO by Infrared Spectroscopies: Theory and Experiments

Thermodynamics of Hydrogen Adsorption and Incorporation at the ZnO(101̅0) Surface

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Product

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ReaxFF Molecular Dynamic Simulations of ZnO Nanocluster and Films in H₂ Atmosphere

ReaxFF Molecular Dynamic Simulations of ZnO Nanocluster and Films in H₂ Atmosphere