Thermal Stability of Single-Crystalline IrO2(110) Layers: Spectroscopic and Adsorption Studies

Marcel J.S. Abb, Tim Weber, Daniel Langsdorf, Volkmar Koller, Sabrina M. Gericke, Sebastian Pfaff, Michael Busch, Johan Zetterberg, Alexei Preobrajenski, Henrik Grönbeck, Edvin Lundgren, Herbert Over

Forskningsoutput: TidskriftsbidragArtikel i vetenskaplig tidskriftPeer review

12 Citeringar (SciVal)

Sammanfattning

The interaction of ultrathin single-crystalline IrO2(110) films with the gas phase proceeds via the coordinatively unsaturated sites (cus), in particular Ircus, the undercoordinated oxygen species on-top O (Oot) that are coordinated to Ircus, and bridging O (Obr). With the combination of different experimental techniques, such as thermal desorption spectroscopy, scanning tunneling microscopy (STM), high-resolution core-level spectroscopy (HRCLS), infrared spectroscopy, and first-principles studies employing density functional theory calculations, we are able to elucidate surface properties of single-crystalline IrO2(110). We provide spectroscopic fingerprints of the active surface sites of IrO2(110). The freshly prepared IrO2(110) surface is virtually inactive toward gas-phase molecules. The IrO2(110) surface needs to be activated by annealing to 500-600 K under ultrahigh vacuum (UHV) conditions. In the activation step, Ircus sites are liberated from on-top oxygen (Oot) and monoatomic Ir metal islands are formed on the surface, leading to the formation of a bifunctional model catalyst. Vacant Ircus sites of IrO2(110) allow for strong interaction and accommodation of molecules from the gas phase. For instance, CO can adsorb atop on Ircus and water forms a strongly bound water layer on the activated IrO2(110) surface. Single-crystalline IrO2(110) is thermally not very stable although chemically stable. Chemical reduction of IrO2(110) by extensive CO exposure at 473 K is not observed, which is in contrast to the prototypical RuO2(110) system.

Originalspråkengelska
Sidor (från-till)15324-15336
Antal sidor13
TidskriftJournal of Physical Chemistry C
Volym124
Utgåva28
DOI
StatusPublished - 2020

Ämnesklassifikation (UKÄ)

  • Fysikalisk kemi
  • Materialkemi
  • Den kondenserade materiens fysik
  • Atom- och molekylfysik och optik

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