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Model Studies on the Ozone-Mediated Synthesis of Cobalt Oxide Nanoparticles from Dicobalt Octacarbonyl in Ionic Liquids.

Ralf SchusterTobias WählerMiroslav KettnerFriederike AgelTanja RetzerPeter WasserscheidJoerg Libuda
Published in: ChemistryOpen (2020)
Low-temperature synthesis in ionic liquids (ILs) offers an efficient route for the preparation of metal oxide nanomaterials with tailor-made properties in a water-free environment. In this work, we investigated the role of 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide [C4 C1 Pyr][NTf2 ] in the synthesis of cobalt oxide nanoparticles from the molecular precursor Co2 (CO)8 with ozone. We performed a model study in ultra-clean, ultrahigh vacuum (UHV) conditions by infrared reflection absorption spectroscopy (IRAS) using Au(111) as a substrate. Exposure of the pure precursor to ozone at low temperatures results in the oxidation of the first layers, leading to the formation of a disordered Cox Oy passivation layer. Similar protection to ozone is also achieved by deposition of an IL layer onto a precursor film prior to ozone exposure. With increasing temperature, the IL gets permeable for ozone and a cobalt oxide film forms at the IL/precursor interface. We show that the interaction with the IL mediates the oxidation and leads to a more densely packed Cox Oy film compared to a direct oxidation of the precursor.
Keyphrases
  • ionic liquid
  • hydrogen peroxide
  • oxide nanoparticles
  • room temperature
  • reduced graphene oxide
  • particulate matter
  • nitric oxide
  • high resolution
  • air pollution
  • single molecule
  • mass spectrometry
  • carbon nanotubes