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MBE Growth and Properties of Model TiO2 Surfaces for Fundamental Studies of Heterogeneous Photocatalysis


EMSL Project ID
19392

Abstract

The overall objective of this project is to provide the field of heterogeneous photocatalysis with unique insights into the molecular-level properties of photocatalytic transformations on TiO2 through joint experimental and theoretical studies of organic photooxidation reactions on model TiO2 materials. Heterogeneous photocatalysis on TiO2 has received considerable attention of late due to increased interest in using light to promote chemical transformations in remediation and energy technologies. Fundamental questions remain unaddressed, including reaction and charge transfer mechanisms, specific surface reaction sites, selectivity, and interplay between thermal and non-thermal processes. The vast majority of research effort has been phemonological and has provided conflicting explanations for such crucial issues as the performance differences between the polymorphs of TiO2 (rutile, anatase or mixtures thereof). In the overall project, molecular-level expertise at PNNL in material synthesis, surface chemistry, theory, photodynamics and scanning probe microscopy will be used to study three areas of fundamental importance to heterogeneous photocatalysis on TiO2. These are: (1) detailed reaction mechanisms, (2) mechanisms of charge transfer, charge trapping and energy redistribution, and (3) surface structure and material dependences, all as they relate to organic photooxidation reactions. The specific goals of this proposal focus on the molecular beam epitaxial (MBE) growth and properties model TiO2 surfaces as testbeds and substrates for fundamental investigations of heterogeneous organic photooxidation reactions and the associated mechanisms. These studies are of direct relevance to DOE?s mission of increasing fundamental scientific understanding of light-to-chemical energy conversions.

Project Details

Project type
Large-Scale EMSL Research
Start Date
2006-07-20
End Date
2009-09-30
Status
Closed

Team

Principal Investigator

Scott Chambers
Institution
Pacific Northwest National Laboratory

Team Members

Dong Kim
Institution
Pacific Northwest National Laboratory

Takeo Ohsawa
Institution
Pacific Northwest National Laboratory

Rui Shao
Institution
Unknown

Michael Henderson
Institution
Pacific Northwest National Laboratory

Ponnusamy Nachimuthu
Institution
Environmental Molecular Sciences Laboratory

Chongmin Wang
Institution
Environmental Molecular Sciences Laboratory

Yingge Du
Institution
Pacific Northwest National Laboratory

Related Publications

Chambers SA, T Ohsawa, CM Wang, I Lyubinetsky, and JE Jaffe. 2009. "Band Offsets at the Epitaxial Anatase TiO2/n-SrTiO3(001) Interface." Surface Science 603(5):771-780.
Li SC, Z Zhang, D Sheppard, BD Kay, JM White, Y Du, I Lyubinetsky, GA Henkelman, and Z Dohnalek. 2008. "Intrinsic Diffusion of Hydrogen on Rutile TiO2(110)." Journal of the American Chemical Society 130(28):9080-9088. doi:10.1021/ja8012825
Ohsawa T, I Lyubinetsky, MA Henderson, and SA Chambers. 2008. "Hole-mediated Photodecomposition of Trimehtyl Acetate on a TiO2(001) Anatase Epitaxial Thin Film Surface." Journal of Physical Chemistry C 112(50):20050-20056. doi:10.1021/jp8077997