ZnO(101̅0) Surface Hydroxylation under Ambient Water Vapor
| Autor: | Sana Rani, J. Anibal Boscoboinik, Chris Arble, Christopher M. Goodwin, Yehia Khalifa, John T. Newberg |
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| Rok vydání: | 2017 |
| Předmět: |
Chemistry
Vapour pressure of water Analytical chemistry 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Dissociation (chemistry) 0104 chemical sciences Surfaces Coatings and Films X-ray photoelectron spectroscopy Monolayer Materials Chemistry Bound water Relative humidity Physical and Theoretical Chemistry 0210 nano-technology Single crystal Water vapor |
| Zdroj: | The Journal of Physical Chemistry B. 122:472-478 |
| ISSN: | 1520-5207 1520-6106 |
| Popis: | The interaction of water vapor with a single crystal ZnO(1010) surface was investigated using synchrotron-based ambient pressure X-ray photoelectron spectroscopy (APXPS). Two isobaric experiments were performed at 0.3 and 0.07 Torr water vapor pressure at sample temperatures ranging from 750 to 295 K up to a maximum of 2% relative humidity (RH). Below 10–4 % RH the ZnO(1010) interface is covered with ∼0.25 monolayers of OH groups attributed to dissociation at nonstoichiometric defect sites. At ∼10–4 % RH there is a sharp onset in increased surface hydroxylation attributed to reaction at stoichiometric terrace sites. The surface saturates with an OH monolayer ∼0.26 nm thick and occurs in the absence of any observable molecularly bound water, suggesting the formation of a 1 × 1 dissociated monolayer structure. This is in stark contrast to ultrahigh vacuum experiments and molecular simulations that show the optimum structure is a 2 × 1 partially dissociated H2O/OH monolayer. The sharp onset to terrace site... |
| Databáze: | OpenAIRE |
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