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Title: Quenching of electron transfer reactions through coadsorption: A study of oxygen photodesorption from TiO 2(110)

Using temperature programmed desorption (TPD) and photon-stimulated desorption (PSD), we show that coadsorbates of varying binding energies on the rutile TiO 2(110) surface exert a commensurate inhibiting influence on the hole-mediated photodesorption of adsorbed O 2. A variety of coadsorbates (Ar, Kr, Xe, N 2, CO, CO 2, CH 4, N 2O, acetone, methanol or water) were shown to quench O 2 photoactivity, with the extent correlating with the coadsorbate's gas phase basicity, which in turn determines the strength of the coadsorbate–Ti 4+ bond. Coadsorbed rare gases inhibited the photodesorption of O 2 by ~ 10–25%, whereas strongly bound species (water, methanol, and acetone) nearly completely inhibited O 2 PSD. We suggest that coadsorption of these molecules inhibit the arrival probability of holes to the surface. Band-bending effects, which vary with the extent of charge transfer between the coadsorbate and the TiO 2(110) surface, are not expected to be significant in the cases of the rare gases and physisorbed species. Furthermore, these results indicate that neutral coadsorbates can exert a significant influence on charge transfer events by altering the interfacial dipole in the vicinity of the target molecule.
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  1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Publication Date:
Report Number(s):
Journal ID: ISSN 0039-6028; PII: S0039602816000054
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Surface Science
Additional Journal Information:
Journal Volume: 117; Journal Issue: C; Journal ID: ISSN 0039-6028
Research Org:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
Country of Publication:
United States
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; photodesorption; TiO2(110); oxygen; photochemistry; coadsorption
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1397340