Reactions of a Polyhalide Ionic Liquid with Copper,Silver, and Gold |
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Authors: | Benjamin May Matthias Lexow Dr Nicola Taccardi Prof?Dr Hans-Peter Steinrück Dr Florian Maier |
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Institution: | 1. Lehrstuhl für Physikalische Chemie II, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058 Erlangen, Germany;2. Lehrstuhl für Chemische Reaktionstechnik, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058 Erlangen, Germany |
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Abstract: | The reactions of copper, silver, and gold with the imidazolium-based polyhalide ionic liquid (IL) C6C1Im]Br2I] were investigated by using X-ray photoelectron spectroscopy (XPS), weight-loss measurements, and gas-phase mass spectrometry. All three Group 11 metals are strongly corroded by the IL at moderate temperatures to give a very high content of dissolved CuI, AgI, and AuI species. The IL–metal solutions are stable against contact with water and air. The replacement of imidazolium with inorganic sodium cations decreased metal corrosion rates by orders of magnitude. Our results clearly indicate metal oxidation by iodide from dibromoiodide anions to form molecular iodine and anionic Br-MI-Br]? (M=Cu, Ag, Au) complexes stabilized by imidazolium counterions. From experiments with a trihalide IL with imidazolium methylated at the 2-position, we ruled out the formation of imidazole–carbene as a cause of the observed corrosion. In contrast to Group 11 metals, molybdenum is inert against the trihalide IL, which is attributed to surface passivation. |
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Keywords: | corrosion ionic liquids metal dissolution photoelectron spectroscopy surface analysis |
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