Model Studies on the Ozone‐Mediated Synthesis of Cobalt Oxide Nanoparticles from Dicobalt Octacarbonyl in Ionic Liquids. Issue 2 (10th September 2020)

• Record Type: Journal Article
• Authors: Schuster, Ralf; Wähler, Tobias; Kettner, Miroslav; Agel, Friederike; Bauer, Tanja; Wasserscheid, Peter; Libuda, Jörg
• Is Part Of: ChemistryOpen. Volume 10:Issue 2(2021)
• Page Start: 141
• Page End: 152
• Publication Date: 2020-09-10
• Subjects: cobalt oxide -- ionic liquids -- IR spectroscopy -- low temperature synthesis -- ozone; Chemistry -- Periodicals; 540; 540.5
• DOI: 10.1002/open.202000187
• Languages: English
• ISSNs: 2191-1363

Abstract

Abstract: 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. Abstract : Low‐temperature & Co .: We investigate the ozone‐mediated preparation of Cox Oy in an IL under UHV to study interactions between the reactants by varying deposition order and temperature of the system. We show that the IL and initially formed Cox Oy layer protect the precursor against oxidation. This effect is lost at elevated temperatures