The Eighth International Workshop on Oxide Surfaces (IWOX VIII)

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Photoactivity of TiO2 rutile and anatase surfaces Mingchun Xu1, Heshmat Noei1, Youkun Gao1, Marinus Kunat2, Hicham Idriss3, Christof Wöll4, Martin Muhler1, and Yuemin Wang1 1 Faculty of Chemistry and Biochemistry, Ruhr-University Bochum, 44801 Bochum, Germany 2Hahn-Meitner-Institut, Glienicker Strasse 100, D-1000 Berlin 39, Germany 3Department of Chemistry, University of Aberdeen and School of Engineering, Robert Gordon University, UK 4Institute of Functional Interfaces (IFG), Karlsruhe Institute of Technology (KIT), 76021 Karlsruhe, Germany <strong>The</strong> photochemistry on semiconductor TiO2 surfaces has recently received enormous attention from both fundamental and technological perspectives because of its applications in the fields of solar energy conversion, water splitting, environmental treatments, etc [1]. In spite of extensive studies, major issues concerning the photoactivity of this important oxide are still under debate. <strong>The</strong> reasons behind the differences in activity between the two most important polymorphs of titania, rutile and anatase, are still not resolved. Here we report the first infrared (IR) study of photoreactions of CO and some organic molecules on TiO2 anatase and rutile surfaces using a novel ultrahigh vacuum (UHV) FTIRS apparatus [2]. <strong>The</strong> high-quality RAIRS data will provide detailed insight into photocatalytic activity and reaction mechanisms on TiO2 surfaces. It was found that the anatase (101) surface exhibits a substantially higher activity for CO photooxidation than the rutile (110) surface. This surprisingly large difference in activity tracks the bulk electron-hole pair life time difference for the two TiO2 modifications. In addition, we will present vibrational spectroscopic study of doping effects on metal oxide photocatalysts [3,4]. References [1] T. L. Thompson and J. T. Yates, Jr., Chem. Rev. 106, 4428 (2006). [2] M. Xu, Y. Gao, E. M. Moreno, M. Kunat, M. Muhler, Y. Wang, H. Idriss, Ch. Wöll, Phys. Rev. Lett. 106, 138302 (2011). [3] M. Xu, Y. Gao, Y. Wang, Ch. Wöll, PCCP 12, 3649 (2010). [4] H. Qiu, F. Gallino, C. Di Valentin, Y. Wang, Phys. Rev. Lett. 106, 066401 (2011).
Preparation, Characterization, and Catalytic Activity of Model WO3 and MoO3 Catalysts Zdenek Dohnalek Pacific Northwest National Laboratory Supported early transition metal oxides (TMO) have important applications in numerous catalytic reactions. In our studies, dehydration and partial oxidation of alcohols are employed to probe the catalytic activity of WO3 and MoO3. To understand how TMO structure and binding affect catalytic properties we prepared a number of well-characterized model systems. Direct sublimation of WO3 and MoO3 solids was used to generate cyclic gas-phase (WO3)n and (MoO3)n clusters. As shown in our matrix isolation experiments sublimation leads to pure (WO3)3 clusters, but results in a range of (MoO3)n cluster sizes (n = 3-6). <strong>The</strong> oxide clusters of both metals were embedded in alcohol matrices and their support-free chemistry was explored in subsequent temperature programmed reaction experiments. Model supported catalysts were created by depositing (WO3)3 clusters on TiO2(110) and FeO(111) and subsequently characterized using scanning tunneling microscopy and surface sensitive spectroscopies. In other studies, epitaxial and nanoporous thin WO3 films were prepared on Pt(111). <strong>The</strong> catalytic chemistry of all the systems is compared and contrasted with that observed on unsupported (WO3)3 clusters. Calculations employing Density Functional <strong>The</strong>ory (DFT) provide molecular-level mechanistic insight into the role structure and binding of (WO3)3 clusters to the support plays in determining their catalytic properties.
Page 1 and 2: The Eighth
Page 3 and 4: Sunday 15 January 21:00 - 22:30 Eve
Page 5 and 6: Wednesday 18 January 08:00 - 09:00
Page 7 and 8: Friday 20 January 08:00 - 09:00 Bre
Page 9 and 10: Ab initio calculation of the MgO(10
Page 11 and 12: Scanning Tunnelling Microscopy imag
Page 13 and 14: New insights into reconstruction of
Page 15 and 16: Abstract Nanostructured TiO2 for Ph
Page 17 and 18: Unraveling the mystery of conductiv
Page 19 and 20: Modeling and understanding structur
Page 21 and 22: Interaction between Ag nanoparticle
Page 23 and 24: Effect of the TiO2 reduction state
Page 25 and 26: Tuning the shape of gold particles
Page 27 and 28: "Thin oxide films: the expected and
Page 29 and 30: V/Ti and Mo/Ti mixed oxide layers o
Page 31 and 32: THEORY OF OXIDES DOPING. TOWARDS A
Page 33 and 34: Structure and Reactivity of Steps o
Page 35 and 36: Toward Surface Science of Metal Oxi
Page 37: Local Environment of Ti 3+ Ions in
Page 41 and 42: Chi YIM - IWOX Abstract The
Page 43 and 44: Reactivity vs. Morphology - Steps o
Page 45 and 46: Ab initio study of Anatase TiO2 sur
Page 47 and 48: Poster Session 1 Surface EXAFS char
Page 49 and 50: The Interaction of
Page 51 and 52: D. Z. Gao, M. B. Watkins, A. L. Shl
Page 53 and 54: Adhesion forces at zinc/α-Al2O3(00
Page 55 and 56: Poster Session 2 Hydrogenation of U
Page 57 and 58: Temperature and field dependent sof
Page 59 and 60: Heats of adsorption and surface rea
Page 61 and 62: Title: Oxidation and reduction of u
Page 63 and 64: The Interaction of

The Eighth International Workshop on Oxide Surfaces (IWOX VIII)

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