Fundamental Studies of Heterogeneous Photocatalysis on Model TiO2 Surfaces
EMSL Project ID
35219
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 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 in the literature has been phemonological, resulting in 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, each 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 porosity.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2009-10-01
End Date
2011-09-30
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. 2010. "Formation of O Adatom Pairs and Charge Transfer upon O-2 Dissociation on Reduced TiO2(110)." Physical Chemistry Chemical Physics. PCCP 12(24):6337-6344.
Du Y, NA Deskins, Z Zhang, Z Dohnalek, M Dupuis, and I Lyubinetsky. 2010. "Water Interactions with Terminal Hydroxyls on TiO2 (110)." Journal of Physical Chemistry C 114(40):17080-17084. doi:10.1021/jp1036876
Du Y, NG Petrik, NA Deskins, Z Wang, MA Henderson, GA Kimmel, and I Lyubinetsky. 2012. "Hydrogen Reactivity on Highly-hydroxylated TiO2(110) Surfaces Prepared via Carboxylic Acid Adsorption and Photolysis." Physical Chemistry Chemical Physics. PCCP 14(9):3066-3074. doi:10.1039/C1CP22515D
Henderson MA. 2010. "Low Temperature Oxidation of Fe2+ Surface Sites on the (2x1) Reconstructed Surface of ?-Fe2O3(01(1) over-bar2)." Surface Science 604(13-14):1197-1201.
Henderson MA. 2010. "Oxygen Plasma Activation of Cr(CO)(6) on ?-Fe2O3(0001)." Surface Science 604(17-18):1502-1508.
Henderson MA. 2012. "Visible Light Induced Photodesorption of NO from the ?-Cr2O3(0001) Surface." Surface Science 606(3-4):505-509. doi:10.1016/j.susc.2011.11.019
Henderson MA, and MD Robbins. 2011. "Methylene Bromide Chemistry and Photochemistry on Rutile TiO2(110)." Surface Science 605(19-20):1834-1841. doi:10.1016/j.susc.2011.06.020
Henderson MA, NA Deskins, RT Zehr, and M Dupuis. 2011. "Generation of Organic Radicals During Photocatalytic Reactions on TiO2." Journal of Catalysis 279(1):205-212.
Lyubinetsky I, NA Deskins, Y Du, EK Vestergaard, DJ Kim, and M Dupuis. 2010. "Adsorption States and Mobility of TMAA Molecules on Reduced TiO2(110) Surface." Physical Chemistry Chemical Physics. PCCP 12(23):5986-5992.
Rajachidambaram MS, A Pandey, S Vilayur Ganapathy, P Nachimuthu, S Thevuthasan, and GS Herman. 2013. "Improved Stability Of Amorphous Zinc Tin Oxide Thin Film Transistors Using Molecular Passivation." Applied Physics Letters 103(17):Article No. 171602. doi:10.1063/1.4826457
Shen M, and MA Henderson. 2011. "Site Competition During Coadsorption of Acetone with Methanol and Water on TiO2(110)." Langmuir 27(15):9430-9438. doi:10.1021/la2016726
Wang Z, NA Deskins, and I Lyubinetsky. 2012. "Direct Imaging of Site-Specific Photocatalytic Reactions of O2 on TiO2(110)." The Journal of Physical Chemistry Letters 3(1):102-106. doi:10.1021/jz2014055
Wang Z, Y Du, Z Dohnalek, and I Lyubinetsky. 2010. "Direct Observation of Site Specific Molecular Chemisorption of O2 on TiO2 (110)." The Journal of Physical Chemistry Letters 1(24):3524-3529. doi:10.1021/jz101535f
Zehr RT, and MA Henderson. 2010. "Thermal chemistry and photochemistry of hexafluoroacetone on rutile TiO2(110) ." Physical Chemistry Chemical Physics. PCCP 12(28):8084-8091.
Zehr RT, NA Deskins, and MA Henderson. 2010. "Photochemistry of 1,1,1-Trifluoroacetone on Rutile TiO2(110)." Journal of Physical Chemistry C 114(40):16900-16908.