Abstract
We present first-principles total-energy calculations of water adsorption on the ZnO(101̄0) surface. We find that on ideal ZnO(101̄0) surfaces, the fully molecular chemisorption is most energetically favorable at coverage ≤0.5ML, whereas at 1 ML, the mixed adsorption with a (2×1) superstructure is most energetically favorable. However, the mixed adsorption with a (2×2) superstructure is only 0.07 eV higher per H2O molecule than the mixed adsorption with a (2×1) superstructure. Therefore, we expect that domains with mixed (2×1) and (2×2) structures may also exist at elevated temperatures. Moreover, we find that oxygen vacancies in the surface significantly affect the adsorption behavior. For an oxygen vacancy density ≤25%, the dissociative adsorption is energetically preferred at water coverage ≤0.25ML and the mixed adsorption is energetically favorable at water coverage ≥0.5ML. The further increase of oxygen vacancy density promotes the dissociative adsorption.
Original language | American English |
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Article number | 235406 |
Number of pages | 6 |
Journal | Physical Review B - Condensed Matter and Materials Physics |
Volume | 72 |
Issue number | 23 |
DOIs | |
State | Published - 15 Dec 2005 |
NREL Publication Number
- NREL/JA-520-37897
Keywords
- dissociative adsorption
- oxygen vacancies
- total-energy calculations
- water adsorption