Density Functional Theory Simulations of Water Adsorption and Activation on the (-201) ß-Ga2 O3 Surface.
Chemistry
; 24(29): 7445-7455, 2018 May 23.
Article
em En
| MEDLINE
| ID: mdl-29520863
ABSTRACT
Density functional theory calculations are used to study the molecular and dissociative adsorption of water on the (-201) ß-Ga2 O3 surface. The effect of adsorption of different water-like species on the geometry, binding energies, vibrational spectra and the electronic structure of the surface are discussed. The study shows that although the hydrogen evolution reaction requires a small amount of energy to become energetically favourable, the over potential for activating the oxygen evolution reaction is quite high. The results of our calculations provide insight as to why a high voltage is required in experiments to activate the water-splitting reaction, whereas previous studies of gallium oxide predicted very low activation energies for other energetically more favourable facets. Application of this work to studies of GaN-based chemical sensors with gallium oxide surfaces shows that it is possible to select the gate bias so that the sensors are not influenced by water-splitting reactions. It was also found that in the region where water splitting does not occur, the surface can exist in two states, that is, water or hydroxyl terminated.
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01-internacional
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MEDLINE
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En
Ano de publicação:
2018
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Article