Hole-mediated Photodecomposition of Trimehtyl Acetate on a TiO2(001) Anatase Epitaxial Thin Film Surface
Surfaces of titanium dioxide in both rutile and anatase polymorphs have attracted significant attention in catalysis and photochemistry. The (110) orientation of rutile, and to a lesser extent other rutile orientations, have been studied on an atomic scale, yielding information on surface structure and chemical reactivity. In contrast, the thermal and photochemistry of well-defined, single-crystal anatase surfaces had not been investigated, largely because of the metastable nature of anatase , as well as the lack of availability of high-quality surfaces. Here we describe a study of the adsorption and photoreactivity of an organic adlayer, trimethyl acetate (TMA), on structurally-excellent anatase (001) epitaxial thin films grown by oxygen plasma assisted molecular beam epitaxy (OPAMBE). High-resolution scanning tunneling microscopy (STM), x-ray photoelectron spectroscopy (XPS), and photodesorption spectrometry have been used to study the chemisorptions and ultraviolet (UV) light-induced photodecomposition of TMA in ultrahigh vacuum. UV light promotes hole-mediated photodecomposition of TMA, resulting in decarboxylation to yield tert-butyl radical and CO2. The photochemical rate constant is equal to that measured for OPAMBE grown rutile TiO2(110) surfaces.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 949112
- Report Number(s):
- PNNL-SA-62399; 19392; KC0302010; TRN: US200907%%401
- Journal Information:
- Journal of Physical Chemistry C, 112(50):20050-20056, Vol. 112, Issue 50; ISSN 1932-7447
- Country of Publication:
- United States
- Language:
- English
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