Titanium dioxide (TiO2) has been extensively studied as a catalyst for a variety of potential applications, and there is a specific need for fundamental studies to address how adsorbates interact with TiO2 surfaces, and how we can tailor their structures to better harvest the catalytic and photocatalytic properties.
In the first part of this talk, I will present our scanning tunneling microscopy (STM) studies of H2O, O2, and their interactions on rutile TiO2(110) surfaces under ultra-high vacuum. By tracking the same surface area before and after molecule exposure, we study the adsorption, dissociation, diffusion, and reaction processes. We show that additional information can be derived by comparing the STM results with ensemble-averaged techniques such as temperature programmed desorption (TPD) and electron stimulated desorption (ESD). The experimental results are also compared with density functional theory (DFT) calculations for a better understanding of the reaction mechanisms. In the second part, I will present our efforts in the growth and characterization of pure and doped anatase TiO2 thin films prepared by molecular beam expitaxy. Structural excellent, epitaxial anatase TiO2(001) films with (4x1) surface reconstructions are grown on Nb doped SrTiO3(001) substrates. While pure anatase thin films are photoactive in the UV region, we show that controlled nitrogen doping can effectively extend the photo activity to the visible region.
Yingge Du (杜英歌), Ph.D.
Environmental Molecular Sciences Laboratory Phone: 509-371-6512
Pacific Northwest National Laboratory
MSIN K8-87, P.O.Box 999, Richland, WA 99352 Email: yingge.du@pnnl.gov
Research Interests
Oxide thin film growth by oxygen plasma /ozone assisted molecular beam epitaxySurface chemistry and photochemistry studied by scanning tunneling microscopyAtomic absorption spectroscopy applications in atomic flux measurement
Education
Ph.D. in Engineering Physics, University of Virginia, Charlottesville, VA (2006)M.S. in Engineering Physics, Tsinghua University, Beijing, China (2001)B.E. in Engineering Physics, Tsinghua University (1998)
Employment
Senior Research Scientist, Environment Molecular Sciences Laboratory (EMSL), Pacific Northwest National Laboratory (PNNL), Richland, WA (2010-present)Post-Doctoral research associate, PNNL (2007-2009)
Publications
Y. Du, N. G. Petrik, N. A. Deskins, Z. Wang, M. A. Henderson, G. A. Kimmel, and I. Lyubinetsky, Hydrogen reactivity on highly-hydroxylated TiO2(110) surfaces prepared via carboxylic acid adsorption and photolysis, PhysChemChemPhys, 14(9), 3066 (2012)Y. Du, D. J. Kim, T. Varga, Z. Wang, J. Szanyi, and I. Lyubinetsky, Formation of single-phase BaO nanoclusters, Thin Solid Films 519(16), 5335 (2011)Y. Du, N. A. Deskins, Z. R. Zhang Z. Dohnalek, M. Dupuis, and I. Lyubinetsky, Formation of O adatom pairs and charge transfer upon O2 dissociation on reduced TiO2(110), PhysChemChemPhys, 12(24), 6337 (2010)I. Lyubinetsky, N. A. Deskins, Y. Du, E. K. Vestergaard, D. J. Kim, and M. Dupuis, Adsorption states and mobility of trimethylacetic acid molecules on redued TiO2(110) surface, PhysChemChemPhys, 12(23), 5986 (2010)Y. Du, N. A. Deskins, Z. zhang, Z. Dohnalek, M. Dupuis and I. Lyubinetsky, Water Interactions with Terminal Hydroxyls on TiO2(110), J. Phys. Chem. C, 114, 17080 (2010)Z.T. Wang, Y. Du, Z. Dohnalek, and I. Lyubinetsky, Direct Observation of Site Specific Molecular Chemisorption of O2 on TiO2(110), J. Phys. Chem. Lett., 1, 3524 (2010)Y. Du, N. A. Deskins, Z. Zhang, Z. Dohnalek, M. Dupuis and I. Lyubinetsky, Two pathways for water interaction with oxygen adatoms on TiO2(110), Phys. Rev. Lett., 102, 096102 (2009).Y. Du, N. A. Deskins, Z. Zhang, Z. Dohnalek, M. Dupuis and I. Lyubinetsky, Imaging O2 Reactions with Hydroxylated TiO2(110), J. Phys. Chem. C, 113, 666 (2009). T. Ohsawa, I. Lyubinetsky, Y. Du, M. A. Henderson, V. Shutthanandan, and S. A. Chambers, Crystallographic dependence of visible-light photoactivity in epitaxial TiO2-xNx anatase and rutile, Phys. Rev. B, 79, 085401 (2009).N. G. Petrik, Z. Zhang, Y. Du, Z. Dohnalek, I. Lyubinetsky, and G. A. Kimmel, Chemical Reactivity of Reduced TiO2(110): The Dominant Role of Surface Defects in Oxygen Chemisorption, J. Phys. Chem. C, 113, 12407 (2009)Z. Zhang, Y. Du, N. G. Petrik, G. A. Kimmel, I. Lyubinetsky, and Z. Dohnalek, Water as a Catalyst: Imaging Reactions of O2 with Partially and Fully Hydroxylated TiO2(110) Surfaces, J. Phys. Chem. C, 113, 1908 (2009).S-C. Li, Z. Zhang, D. Sheppard, B. D. Kay, J. M. White, Y. Du, I. Lyubinetsky, G. Henkelman, and Z. Dohnalek, Intrinsic Diffusion of Hydrogen on Rutile TiO2(110), J. Am. Chem. Soc., 130, 9080 (2008). Y. Du, Z. Dohnalek, and I. Lyubinetsky, Transient Mobility of Oxygen Adatoms upon O2 Dissociation on Reduced TiO2 (110), J. Phys. Chem. C, 112, 2649 (2008). (Featured Journal Cover)Z. Q. Yu, C. M. Wang, Y. Du, S. Thevuthasan, and I. Lyubinetsky, Reproducible Tip Fabrication and Cleaning for UHV STM, Ultramicroscopy, 108(9), 873 (2008).J. F. Groves, Y. Du, I. Lyubinetsky, and D. R. Baer, Focused Ion Beam Directed Self-Assembly (Cu2O on SrTiO3): FIB Pit and Cu2O Quantum Dot Evolution, Superlattices and Microstructures, 44, 677 (2008).Y. Du, J. F. Groves, I. Lyubinetsky, and D. R. Baer, Formation of Cu2O Quantum Dots on SrTiO3 (100): Self-Assembly and Directed Self-Assembly, J. Appl. Phys., 100(9), 094315, (2006).Y. Du, S. Atha, R. Hull, J. F. Groves, I. Lyubinetsky, and D. R. Baer, Focused Ion Beam Directed Self-Assembly of Cu2O islands on SrTiO3 (100), Appl. Phys. Lett., 84(25), 5213 (2004).C. Bao, Y. Du, T. Chi, Y. Wang, L. Zhang, L. Wang, and D. Wang, Manufacture and Research of the Linear-source Metal Atomic Evaporation Device, Chinese J. Lasers, 30(5) 457 (2003).Y. Du, C. Bao, and D. Wang, Theoretical and Experimental Research of the Drilled Magnetic Field, J. Chinese Mass Spectrom.Soc., 22(2), 46 (2001).