Multiple Non-Thermal Reaction Steps for the Photooxidation CO to CO2 on Reduced TiO2(110)

Journal Article · Thu Feb 07 04:00:00 EST 2013 · The Journal of Physical Chemistry Letters, 4(3):344-349

DOI:https://doi.org/10.1021/jz302012j· OSTI ID:1073568

Petrik, Nikolay G.; Kimmel, Gregory A.

The photooxidation of CO on reduced, rutile TiO2(110) was studied on a millisecond timescale. For a saturation coverage of chemisorbed O2 (0sat) and for half that coverage, the CO2 photon-stimulated desorption (PSD) signal is initially zero, increases to a maximum after several tens of milliseconds, and then decreases at longer times. The CO2 PSD signal increases ~5 times more quickly for 0.50sat. The initial rate of increase of the CO2 PSD signal is proportional to the flux of UV photons. The intermediate species involved in the reactions is stable for at least 100 s at 30 K. These results show that two or more non-thermal reaction steps are required to photooxidize CO adsorbed on TiO2(110). In contrast, previous models had suggested that CO photooxidation required only one non-thermal reaction. The likely initial and final charge states of the system suggest that an electron-mediated reaction and a hole-mediated reaction are needed for the complete photooxidation reaction.

• 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: 1073568
• Report Number(s): PNNL-SA-92421; 47406; KC0301020
• Journal Information: The Journal of Physical Chemistry Letters, 4(3):344-349, Journal Name: The Journal of Physical Chemistry Letters, 4(3):344-349
• Country of Publication: United States
• Language: English

Related Subjects

Environmental Molecular Sciences Laboratory