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VERSION:2.0
PRODID:icalendar-ruby
CALSCALE:GREGORIAN
X-WR-CALNAME:EPSSI Seminar: Gareth Parkinson\, Vienna University of Technol
 ogy (TU Wein)
X-WR-TIMEZONE:Eastern Time (US & Canada)
BEGIN:VEVENT
DTSTAMP:20261006T175013Z
UID:tag:localist.com\,2008:EventInstance_34651330450442
DTSTART:20201102T210000Z
DTEND:20201102T220000Z
DESCRIPTION:Structure and Chemistry of Iron-Oxide Surfaces\n\n \n\nIron oxi
 des are omnipresent in the natural environment on Earth\, and have been fo
 und to exist in large amounts on our Moon as well as Mars. Reactions happe
 ning at mineral surfaces play an important role in geo- and atmospheric ch
 emistry\, and we have found many opportunities to use the reactivity of th
 ese materials in catalysis. The seminar will focus on atomic-scale studies
  of processes occurring at the surfaces of hematite (α-Fe2O3) and magneti
 te (Fe3O4) single crystals (1). Single crystal samples are prepared in vac
 uum such that the structure is precisely known (2\, 3)\, and adsorption/re
 activity is probed via a combination of scanning probe microscopies and el
 ectron spectroscopies. This provides an ideal complement to density functi
 onal theory (DFT) calculations\, and allows a complete picture to be devel
 oped. In recent times\, we have extended our work to include studies in am
 bient pressure and ultra-pure liquid water environments (4)\, and this wil
 l be the primary topic of the presentation. We find that partially dissoci
 ated water agglomerates are the most stable species on both the Fe2O3(012)
  and Fe3O4(001) surfaces in UHV (5-7)\, and that significant oxygen exchan
 ge occurs during water desorption from the hematite surface. Such a proces
 s does not occur on magnetite\, but Fe3O4(001) undergoes a self-limited tr
 ansformation to an (oxy)hydroxide phase at pH7 (8)\, and dissolves if CO2 
 is permitted to acidify the water during the experiment (9).\n\n1.  G. S. 
 Parkinson\, Iron oxide surfaces. Surf. Sci. Rep. 71\, 272-365 (2016).\n\n2
 .  R. Bliem et al.\, Subsurface cation vacancy stabilization of the magnet
 ite (001) surface. Science 346\, 1215-1218 (2014).\n\n3.  F. Kraushofer et
  al.\, Atomic-Scale Structure of the Hematite α-Fe2O3(11̅02) “R-Cut”
  Surface. J. Phys. Chem. C 122\, 1657-1669 (2018).\n\n4.  J. Balajka et al
 .\, High-affinity adsorption leads to molecularly ordered interfaces on Ti
 O2 in air and solution. Science 361\, 786 (2018).\n\n5.  M. Meier et al.\,
  Water agglomerates on Fe3O4(001). Proc. Natl. Acad. Sci. U.S.A. 115\, E56
 42- E5650 (2018).\n\n6.  Z. Jakub et al.\, Partially Dissociated Water Dim
 ers at the Water-Hematite Interface. ACS Energy Letters\, (2019).\n\n7.  E
 . Zaki et al.\, Water Ordering on the Magnetite Fe3O4 Surfaces. J. Phys. C
 hem. Lett. 10\, 2487- 2492 (2019).\n\n8.  F. Kraushofer et al.\, Self-limi
 ted growth of an oxyhydroxide phase at the Fe3O4(001) surface in liquid an
 d ambient pressure water. J. Chem. Phys. 151\, 154702 (2019).\n\n9.  F. Mi
 rabella et al.\, Atomic-Scale Studies of Fe3O4(001) and TiO2(110) Surfaces
  Following Immersion in CO2-Acidified Water. ChemPhysChem 21\, 1788-1796 (
 2020).
LOCATION:
SUMMARY:EPSSI Seminar: Gareth Parkinson\, Vienna University of Technology (
 TU Wein)
URL;VALUE=URI:https://events.mtu.edu/event/epssi_seminar_gareth_parkinson_v
 ienna_university_of_technology_tu_wein
CATEGORIES:Academics
CATEGORIES:Lectures/Seminars
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