Mayr-Schmölzer, W., Halwidl, D., Mittendorfer, F., Schmid, M., Diebold, U., & Redinger, J. (2019). Adsorption of CO on the Ca₃Ru₂O₇(001) surface. Surface Science, 680, 18–23. https://doi.org/10.1016/j.susc.2018.10.004
Condensed Matter Physics; Surfaces, Coatings and Films; Materials Chemistry; Surfaces and Interfaces; Calcium ruthenate Ca3Ru2O7 CO Carbon monoxide Carboxylate STM DFT
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Abstract:
The adsorption of CO molecules at the Ca3Ru2O7(001) surface was studied using low-temperature scanning
tunneling microscopy (STM) and density functional theory (DFT). Ca3Ru2O7 can be easily cleaved along the
(001) plane, yielding a smooth, CaO-terminated surface. The STM shows a characteristic pattern with alternating
dark and bright stripes, resulting from the tilting of the RuO6 octahedra. At 78 K, CO adsorbs at an apical surface
O at the channel edge with a predicted binding energy of Eads = −0.85 eV. After annealing at room temperature,
the CO forms a strong bond (Eads = −2.04 eV) with the apical O and the resulting carboxylate takes the place of
the former surface O. This carboxylate can be decomposed by scanning the surface with a high sample bias
voltage of +2.7 V, restoring the original surface.
