ChemInform Abstract: Absence of Platinum Enhancement of a Photoreaction on TiO2‐CO Photooxidation on Pt/TiO2(110).

Linsebigler, Amy; Rusu, C. N.; Yates, John T.

doi:10.1002/chin.199639028

Cited by 2 publications

(2 citation statements)

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“…Photocatalysis has received remarkable interest as a green and sustainable solution for the energy and environmental issues since Fujishima and Honda’s first reports of UV-light-induced redox chemistry on TiO 2 . This consequently has intrigued the fundamental investigations of photochemistry of TiO 2 surface largely employing rutile TiO 2 (110) surface as the prototypical model surface. − Insights have been recently achieved into the photochemistry of several important molecules involved in photocatalytic reactions, such as O 2 , − CO, − methanol/formaldehyde, − H 2 O, − and H adatoms …”

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confidence: 99%

Surface Chemistry of Formaldehyde on Rutile TiO₂(110) Surface: Photocatalysis vs Thermal-Catalysis

et al. 2014

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The photocatalytic surface reactions of formaldehyde (HCHO) on rutile TiO 2 (110) surface were studied by means of thermal desorption spectroscopy and X-ray photoelectron spectroscopy and compared with its thermally catalytic surface reactions. Thermally catalytic surface reactions of formaldehyde on rutile TiO 2 (110) surface are dominated by the carbon−carbon bond formation reaction of HCHO adsorbed at oxygen vacancies to produce C 2 H 4 via a diolate (−OCH 2 CH 2 O−) surface intermediate. During the photocatalytic surface reactions, HCHO adsorbed at the Ti 5c sites of rutile TiO 2 (110) surface is photocatalytically oxidized to a transient formyl (HCO) species that facilely transforms to adsorbed formate (HCOO) species. HCOO species and HCHO adsorbed at oxygen vacancies undergo novel surface reactions to produce CO, C 2 H 4 , and CH 3 OH at elevated temperatures whose mechanisms were successfully identified. The healing of bridging oxygen vacancies on rutile TiO 2 (110) surface by preadsorption of water suppresses the oxygen vacancy-mediated coupling reaction of formaldehyde but does not affect its photocatalytic surface reactions. These results not only greatly deepen the fundamental understanding of photochemistry of formaldehyde on TiO 2 surface but also demonstrate novel surface reactions of organic functional groups formed by the combined photocatalytic and thermally catalytic reactions of formaldehyde on oxide surfaces.

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Section: Introductionmentioning

confidence: 99%

Surface Chemistry of Formaldehyde on Rutile TiO₂(110) Surface: Photocatalysis vs Thermal-Catalysis

et al. 2014

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“…The reactions between CO and O 2 have been studied in detail on metals, − and it is a model system for studying the mechanisms of thermal oxidation and photooxidation on TiO 2 . Yates and co-workers investigated the photooxidation of CO on TiO 2 (110) at ∼100 K and found that UV irradiation led to either photodesorption of chemisorbed O 2 or photooxidation of CO to CO 2 . ,, The energy thresholds for both O 2 and CO 2 photon-stimulated desorption (PSD) were at ∼3.1 eV, corresponding to the band gap of TiO 2 . This threshold indicates that the photochemistry is initiated by the generation of electron−hole pairs in the substrate.…”

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confidence: 99%

Off-Normal CO₂ Desorption from the Photooxidation of CO on Reduced TiO₂(110)

Petrik

Kimmel

2010

J. Phys. Chem. Lett.

112

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Photoinduced reactions between O2 and CO on reduced rutile TiO2(110) are studied at low temperature (∼30 K). Photon-stimulated desorption (PSD) of O2, CO2, and CO is observed with comparable yields. Isotope labeling experiments indicate that O2 chemisorbed in a vacancy is more active for photooxidation than O2 chemisorbed on a Ti5c site. The angular distribution for the desorbing CO2 is peaked at ∼40° with respect to the surface normal in the [11̅0] azimuth (i.e., perpendicular to the bridging oxygen rows), suggesting that CO2 is produced from O2 occupying an oxygen vacancy and CO adsorbed on a Ti5c site next to it. The experimental results are consistent with CO2 being produced from a transition state that has been predicted theoretically. The CO PSD from TiO2(110) is enhanced dramatically by the presence of chemisorbed O2, suggesting that it is a byproduct of the CO photooxidation process.

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ChemInform Abstract: Absence of Platinum Enhancement of a Photoreaction on TiO2‐CO Photooxidation on Pt/TiO2(110).

Cited by 2 publications

References 1 publication

Surface Chemistry of Formaldehyde on Rutile TiO₂(110) Surface: Photocatalysis vs Thermal-Catalysis

Surface Chemistry of Formaldehyde on Rutile TiO₂(110) Surface: Photocatalysis vs Thermal-Catalysis

Off-Normal CO₂ Desorption from the Photooxidation of CO on Reduced TiO₂(110)

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ChemInform Abstract: Absence of Platinum Enhancement of a Photoreaction on TiO2‐CO Photooxidation on Pt/TiO2(110).

Cited by 2 publications

References 1 publication

Surface Chemistry of Formaldehyde on Rutile TiO2(110) Surface: Photocatalysis vs Thermal-Catalysis

Surface Chemistry of Formaldehyde on Rutile TiO2(110) Surface: Photocatalysis vs Thermal-Catalysis

Off-Normal CO2 Desorption from the Photooxidation of CO on Reduced TiO2(110)

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Product

Resources

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Surface Chemistry of Formaldehyde on Rutile TiO₂(110) Surface: Photocatalysis vs Thermal-Catalysis

Surface Chemistry of Formaldehyde on Rutile TiO₂(110) Surface: Photocatalysis vs Thermal-Catalysis

Off-Normal CO₂ Desorption from the Photooxidation of CO on Reduced TiO₂(110)