Imaging Consecutive Steps of O2 Reaction with Hydroxylated TiO2(110): Identification of HO2 and Terminal OH Intermediates

Journal Article · Thu Jan 15 04:00:00 EST 2009 · Journal of Physical Chemistry C, 113(2):666-671

DOI:https://doi.org/10.1021/jp807030n· OSTI ID:964610

Du, Yingge; Deskins, N Aaron; Zhang, Zhenrong; Dohnalek, Zdenek; Dupuis, Michel; Lyubinetsky, Igor

The hydroperoxyl (HO2) species is believed to be a key intermediate in many heterogeneous photochemical processes, but generally metastable and thus hard to prove. We report here that for the first time, we directly imaged stable, adsorbed HO2 species during O2 reaction with a partially hydroxylated TiO2(110). We also found terminal hydroxyl groups, another critical but never directly observed intermediates. By imaging species and tracking site-specific reactions with high-resolution scanning tunneling microscopy, and determining the energies and configurations with density functional theory calculations, we provide molecular-level insight into the underlying reaction mechanisms. These results are expected to have far reaching implications for various catalytic systems involving the interconversion of O2 and H2O.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 964610
• Report Number(s): PNNL-SA-60868; 19392; 25619; KC0302010
• Journal Information: Journal of Physical Chemistry C, 113(2):666-671, Journal Name: Journal of Physical Chemistry C, 113(2):666-671 Journal Issue: 2 Vol. 113; ISSN 1932-7447
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
CHEMICAL REACTION KINETICS
DENSITY FUNCTIONAL METHOD
Environmental Molecular Sciences Laboratory
HYDROPEROXY RADICALS
HYDROXYL RADICALS
OXIDATION
PHOTOCHEMISTRY
REACTION INTERMEDIATES
SCANNING TUNNELING MICROSCOPY
TITANIUM OXIDES