Phosphonic Acids on Well-Ordered CoO Surfaces: The Binding Motif Depends on the Surface Structure

Journal article

Publication Details

Author(s): Schuschke C, Schwarz M, Hohner C, Silva TN, Libuda J
Journal: Journal of Physical Chemistry C
Publication year: 2018
Volume: 122
Journal issue: 28
Pages range: 16221-16233
ISSN: 1932-7447


In this work, we investigate the interaction of deuterated phenylphosphonic acid (DPPA, C6H5PO3D2) with two different well ordered cobalt-oxide thin films, CoO(111) and CoO(100), grown on Ir(100). We applied coverage-dependent infrared reflection absorption spectroscopy (IRAS) and temperature-programmed (TP)-IRAS under ultrahigh vacuum conditions to study surface reactions, film growth, and thermal stability, both in monolayer and multilayer regimes. The results are compared to our previous studies on Co3O4(111). In the multilayer regime, amorphous multilayer films of DPPA are formed at a low temperature (180 K), which are very similar on all surfaces. At 250 K, the multilayer films crystallize, leading to changes in the molecular orientation relative to the surface. Above 340 K, the multilayer desorbs while only the chemically anchored monolayer remains on the surface. The monolayer films on all three surfaces are stable up to at least 400 K. Coverage and binding geometry, however, depend sensitively on the structure of the oxide surface. On CoO(100), DPPA undergoes complete deprotonation and anchors to the surface forming a fully deprotonated tridentate phosphonate, which dominates over the full range of coverages. On the oxygen terminated CoO(111), we find, in contrast, the formation of a bidentate species in the limit of zero coverage. At a higher coverage, we observe full deprotonation and the formation of tridentate species, which we attribute to the restructuring of the surface. The behavior differs from Co3O4(111), where DPPA forms a fully deprotonated tridentate phosphonate at a low coverage and a partially protonated bidentate phosphonate at higher coverage.(1) The different binding motifs are discussed in view of the arrangement of surface Co ions on the three oxide surfaces.

FAU Authors / FAU Editors

Hohner, Chantal
Lehrstuhl für Physikalische Chemie II
Libuda, Jörg Prof. Dr.
Professur für Physikalische Chemie
Schuschke, Christian
Lehrstuhl für Physikalische Chemie II
Schwarz, Matthias
Lehrstuhl für Physikalische Chemie II

Additional Organisation
Exzellenz-Cluster Engineering of Advanced Materials

How to cite

Schuschke, C., Schwarz, M., Hohner, C., Silva, T.N., & Libuda, J. (2018). Phosphonic Acids on Well-Ordered CoO Surfaces: The Binding Motif Depends on the Surface Structure. Journal of Physical Chemistry C, 122(28), 16221-16233.

Schuschke, Christian, et al. "Phosphonic Acids on Well-Ordered CoO Surfaces: The Binding Motif Depends on the Surface Structure." Journal of Physical Chemistry C 122.28 (2018): 16221-16233.


Last updated on 2019-20-02 at 08:38