Fundamental Studies of Heterogeneous Photocatalysis on Model TiO2 Surfaces
EMSL Project ID
19804
Abstract
The 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, e.g., 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 this 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. These issues will be explored using a variety of model TiO2 systems including single crystal surfaces and epitaxially grown films of rutile and anatase, mixed phase films of the two, and surfaces prepared with controlled structural and electronic defects and varying degrees of nano-porosity. 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
2006-10-01
End Date
2009-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members
Related Publications
Du Y, NA Deskins, Z Zhang, Z Dohnalek, M Dupuis, and I Lyubinetsky. 2009. "Two Pathways for Water Interaction with Oxygen Adatoms on TiO2(110)." Physical Review Letters 102(9):Art. No. 096102. doi:10.1103/PhysRevLett.102.096102
J.F. Groves, Y. Du, I. Lyubinetsky, D.R. Baer, "Focused Ion Beam Directed Self-Assembly (Cu2O on SrTiO3): FIB Pit and Cu2O Quantum Dot Evolution", Superlattices and Microstructures 44 (2008) 677-85
N.G. Petrik, Z. Zhang, Y. Du, Z. Dohnálek, I. Lyubinetsky, and G.A. Kimmel, "The Chemical Reactivity of Reduced TiO2(110): The Dominant Role of Surface Defects in Oxygen Chemisorption", J. Phys. Chem. C 113 (2009) 12407.
Y. Du, N.A. Deskins, Z. Zhang, Z. Dohnálek, M. Dupuis, and I. Lyubinetsky, Formation of O Adatom Pairs and Charge Transfer upon O2 Dissociation on Reduced TiO2(110), Phys. Chem. Chem. Phys. 12 (2010) 6337
Y. Du, Z. Dohnálek, and I. Lyubinetsky, "Transient Mobility of Oxygen Adatoms upon O2 Dissociation on Reduced TiO2 (110)", J. Phys. Chem. C 112 (2008) 2649-53.
Zehr RT, and MA Henderson. 2008. "Acetaldehyde photochemistry on TiO2(110)." Surface Science 602(13):2238-2249. doi:10.1016/j.susc.2008.04.045
Z.Q. Yu, C.M. Wang, Y. Du, S. Thevuthasan, and I. Lyubinetsky, "Reproducible Tip Fabrication and Cleaning for UHV STM", Ultramicroscopy 108 (2008) 873-7.
Z. Zhang, Y. Du, N.G. Petrik, G.A. Kimmel, I. Lyubinetsky, and Z. Dohnálek, "Water as a Catalyst: Imaging Reactions of O2 with Partially and Fully Hydroxylated TiO2(110) Surfaces", J. Phys. Chem. C 113 (2009) 1908?1916.