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O2 interaction and reactivity on a model hydroxylated rutile(110) surface
Antonio Tilocca1, Cristiana Di Valentin, Annabella Selloni
1Department of Chemistry, Princeton University, Princeton, NJ 08544, USA.
The Journal of Physical Chemistry. B
|July 21, 2006
Summary
Oxygen reacts directly with hydroxylated TiO2 surfaces, forming peroxide intermediates. These findings explain experimental observations in photocatalysis and oxygen scavenging, advancing surface chemistry understanding.
Area of Science:
- Surface science
- Computational chemistry
- Materials science
Background:
- Titanium dioxide (TiO2) photocatalysis and oxygen scavenging are influenced by surface hydroxyls.
- Previous studies focused on oxygen adsorption on clean TiO2(110).
Purpose of the Study:
- Investigate the chemistry of O2 on hydroxylated TiO2 surfaces.
- Clarify reaction pathways and intermediate species.
Main Methods:
- First-principles total energy calculations
- Molecular dynamics (MD) simulations
Main Results:
- MD simulations reveal spontaneous reaction between O2 and surface hydroxyls.
- Peroxide species (HO2 and H2O2) identified as stable chemisorbed intermediates.
- Energetics suggest intermediate transformation linked to experimental 300 K TPD feature.
Conclusions:
- The reaction between O2 and hydroxylated TiO2 does not require a pre-adsorbed O2 state.
- Peroxide intermediates play a key role in the reaction mechanism.
- Further transformations of intermediates may explain observed desorption spectra.