STM movies of the diffusion of single O atoms in a full layer of CO molecules on a Ru(0001) surface show how particles can move on a catalyst surface, even when the surface is highly covered by adsorbates. Surprisingly, the O atoms move through the CO layer almost as fast as on the completely empty metal surface. The mechanism may be called “door-opening” mechanism.
The article shows that a nickel layer used as support for graphene can
be removed from underneath the graphene layer by reaction with CO. The
photograph shows the reaction tube with the sample (blue) after the
nickel has been removed; the transported Ni appears as dark precipitate
on the tight hand side of the tube.
Reprinted from "Detachment of CVD-grown graphene from single-crystalline Ni films by a pure gas phase reaction", P. Zeller, A.-K. Henß, M. Weinl, L. Diehl, D. Keefere, J. Lippmann, A. Schulz, J. Kraus, M. Schreck, J. Wintterlin, Surf. Sci. 653, 143 (2016). Copyright 2016, with permission from Elsevier.
STM image demonstrating that CO molecules can dissociate on a Co(0001)
surface, an essential step in the Fischer-Tropsch reaction. The hexagonal
pattern is formed by the intact CO molecules; the triangles are structures
caused by C atoms resulting from the dissociation of CO molecules (see
model with black carbon atoms). The image was recorded with a special "
high-pressure" STM under 0.22 mbar CO at 493 K. 600 Å x 600 Å.
Adapted with permission from "In situ scanning tunneling microscopy of the dissociation of CO on Co(0001)", B. Böller, M. Ehrensperger, J. Wintterlin, ACS Catal. 5, 6802 (2015). Copyright 2015, American Chemical Society
On Dec. 11, 2015, Bernhard Böller was awarded the Römer prize by the Dr. Klaus Römer-Stiftung for his master thesis "Dissoziation von Kohlenmonoxid auf der Cobalt(0001)-Oberfläche - eine in situ-Studie mit dem Rastertunnelmikroskop".
Awarded on Dec. 11, 2015, by the Fachschaft der Fakultät Chemie und Pharmazie.
Movie recorded with a photoemission electron microscope (PEEM). It shows
that a defect-rich graphene layer grown on a nickel surface can be healed,
in contrast to expectations. In the beginning, the graphene layer exhibits
areas with different contrast levels due to domains with different
orientations or to bilayer graphene. During annealing at 700 °C the dark,
"wrongly" oriented and bilayer graphene domains dissolved and were
replaced by the bright, "correctly" oriented monolayer graphene. From a
collaboration with the groups of M. Schreck (Univ. Augsburg) and
T. Seyller (TU Chemnitz).
Reprinted with permission from "Healing of graphene on single crystalline Ni(111) films", P. Zeller, F. Speck, M. Weinl, M. Ostler, M. Schreck, T. Seyller, J. Wintterlin, Appl. Phys. Lett. 105, 191612 (2014). Copyright 2014, AIP Publishing LLC.
On Dec. 5, 2014, Ann-Kathrin Henß was awarded the Römer prize by the Dr. Klaus Römer-Stiftung for her master thesis "Untersuchungen zur Synthese von freistehendem Graphen ausgehend von dünnen Ni(111)-Filmen".
Image taken with a special high-pressure STM, showing an operating
Fischer-Tropsch model catalyst with atomic resolution. It was recorded
on a Co(0001) surface in 10 mbar "syngas" (a mixture of CO and H2) at
493 K, during formation of methane, the first product in the series of
hydrocarbon molecules formed by the Fischer-Tropsch synthesis. Except
for atomic steps and some lattice deformations the surface was flat,
in contrast to previous ideas about the state of the active surface.
2300 Å x 2300 Å.
Reprinted from "In situ high-pressure high-temperature scanning tunneling microscopy of a Co(0001) Fischer-Tropsch model catalyst", M. Ehrensperger, J. Wintterlin, J. Catal. 319, 274 (2014). Copyright 2014, with permission from Elsevier.
Movie recorded with a low-energy electron microscope (LEEM) (field of
view 4.8 µm; the colored image to the right is the last frame of the
movie). The data show an oxygen-covered silver surface, with oxygen
atoms condensed in islands (dark); the bare silver surface appears
bright. The movie was taken at 487 K, a temperature at which oxygen
desorbs from the surface. The oxygen atoms only desorbed from the
perimeters of the oxygen islands rather than from statistical positions,
presumably a quite general effect. From a collaboration with the groups
of S. Günther (TUM) and A. Locatelli (ELETTRA).
From "Desorption kinetics from a surface derived from direct imaging of the adsorbate layer", S. Günther, T. O. Mentes, M. A. Mino, A. Locatelli, S. Böcklein, J. Wintterlin, Nature Comm. 5, 3853 (2014).
On Dec. 13, 2013 Sebastian Böcklein was awarded the Römer prize by the Dr. Klaus Römer-Stiftung for his PhD thesis "Untersuchungen zur katalytischen Ethylenepoxidierung über Silber - Überbrückung des pressure gap-Problems".
Awarded on Nov. 30, 2012, by the Dr. Klaus Römer-Stiftung, for her master thesis "Untersuchungen zur Ethylen-Epoxidierung".
Series of STM images, taken during epitaxial growth of graphene on a
ruthenium surface at 665 °C. A special high-temperature STM has been
used. The growing graphene layer reshapes the terrace structure of the
metal. 7700 Å x 7700 Å.
From "Single terrace growth of graphene on a metal surface", S. Günther, S. Dänhardt, B. Wang, M.-L. Bocquet, S. Schmitt, J. Wintterlin, Nano Lett. 11, 1895 (2011).
Awarded on Dec. 9, 2011, by the Dr. Klaus Römer-Stiftung, for his master thesis "Versuche zur Strukturlösung einer Silber-Sauerstoff-Oberflächenspezies mit der Methode der LEED-I/V-Analyse".
Structure model of a graphene monolayer on a ruthenium surface. One
would expect that graphene only binds weakly, by van der Waals interactions,
to a metal surface. However, the structure model for graphene on Ru(0001)
obtained by a LEED-I(V) analysis, showed a strong buckling of the graphene
layer (~1.5 Å), indicating a considerable variation of the bonding strength
along the surface. This is the structure with the largest unit cell that
has so far been solved by a LEED-I(V) analysis.
Reprinted with permission from " Structure determination of the coincidence phase of graphene on Ru(0001)", W. Moritz, B. Wang, M.-L. Bocquet, T. Brugger, T. Greber, J. Wintterlin, S. Günther, Phys. Rev. Lett. 104, 136102 (2010). Copyright 2010, American Physical Society.
Awarded on Dec. 3, 2010, by the Dr. Klaus Römer-Stiftung, for his master thesis "Untersuchungen an Graphen auf Ir(111)-Metallfilmen".
"Graphene on metal surfaces", J. Wintterlin and M.-L. Bocquet, Surf. Sci. 603, 1841 (2009). A review article on epitaxial graphene on metal surfaces that, by Jan. 2017, has been cited 527 times.
Awarded to Sebastian Böcklein (second from left) on Dec. 11, 2009, by the Dr. Klaus Römer-Stiftung, for his diploma thesis "Untersuchungen zum Hochdruckverhalten des Ag(111)/O-Systems".