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Title: Comparison of the Photodesorption Activities of cis-Butene, trans-Butene and Isobutene on the Rutile TiO2(110) Surface

The chemical and photochemical properties of three butene molecules (cis-butene, trans-butene and isobutene) were explored on the clean rutile TiO2(110) surface using temperature programmed desorption (TPD) and photon simulated desorption (PSD). At the low coverage limit, trans-butene was the most strongly bound butene on the TiO2(110) surface, desorbing at ~ 210 K, however increased intermolecular repulsions between trans-butene molecules at higher coverage diminished its binding. Both cis-butene and isobutene saturated the first layer on TiO2(110) at a coverage of ~0.50 ML in a single TPD feature at 184 and 192 K, respectively. In contrast, the maximum coverage that trans-butene could achieve in its 210 K peak was ~1/3 ML, with higher coverages resulting a low temperature desorption at ~137 K. Coverages of these molecules above 0.50 ML resulted in population of second layer and multilayer states. The instability of trans-butene at a coverage of 0.5 ML on the surface was linked to the inversion center in its symmetry. In the absence of coadsorbed oxygen, the primary photochemical pathway of each butene molecule on TiO2(110) was photodesorption. The photoactivities of these molecules on TiO2(110) at an initial coverage of 0.50 ML followed the trend: isobutene > cis-butene > trans-butene. In contrast,more » the photoactivities of low coverages of cis-butene and trans-butene exceeded those measured at 0.50 ML. These data suggest that intermolecular interactions (repulsions) play a significant role in diminishing the photoactivities of weakly bound molecules on TiO2 photocatalysts. Work reported here was supported by the U.S. Department of Energy, Office of Basic Energy Science, Division of Chemical Sciences, Geosciences, and Biosciences, and performed in the Williams R. Wiley Environmental Molecular Science Laboratory (EMSL), a Department of Energy user facility funded by the Office of Biological and Environmental Research. Pacific Northwest National Laboratory is a multiprogram national laboratory operated for the U.S. Department of Energy by the Battelle Memorial Institute under contract DEAC05-76RL01830.« less
  1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Publication Date:
OSTI Identifier:
Report Number(s):
Journal ID: ISSN 1932-7447; 47406; KC0302010
DOE Contract Number:
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Physical Chemistry. C; Journal Volume: 117; Journal Issue: 45
American Chemical Society
Research Org:
Pacific Northwest National Laboratory (PNNL), Richland, WA (United States), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org:
Country of Publication:
United States
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY surface photochemistry; rutile TiO2(110); isobutene; cis-butene; trans-butene; temperature programmed desorption; photon stimulated desorption; Environmental Molecular Sciences Laboratory