Structure and Reactivity of the Ionic Liquid [C(1)C(1)Im][Tf2N] on Cu(111)

Adhikari R, Massicot S, Fromm L, Talwar T, Gezmis E, Meusel M, Bayer A, Jaekel S, Maier F, Görling A, Steinrück HP (2023)

Publication Type: Journal article

Publication year: 2023


DOI: 10.1007/s11244-023-01801-y


We studied the adsorption and reaction behavior of the ionic liquid (IL) 1,3-dimethylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([C(1)C(1)Im][Tf2N]) on Cu(111) using non-contact atomic force microscopy (nc-AFM), scanning tunneling microscopy (STM), and angle-resolved X-ray photoelectron spectroscopy (ARXPS) in ultrahigh vacuum as a function of temperature, supported by density-functional theory (DFT) calculations. Our nc-AFM results for sub-monolayer IL films show that at 200 K, the IL self-assembles into highly ordered islands, with cations and anions arranged next to each other in a checkerboard-type phase. After extended annealing at 300 K, the structure transforms first to a hexagonal phase and then to a porous honeycomb phase. Simultaneously, many small, disordered islands are formed. Complementary ARXPS reveals no IL desorption until 300 K. However, a significant fraction of the IL is converted to a new species as deduced from new, strongly shifted peaks that develop in the XP spectra at around 275 K and grow with annealing time at 300 K. We correlate the remaining unshifted peaks to the ordered phases observed in nc-AFM and the shifted peaks to decomposition products, which appear as disordered islands in nc-AFM and STM. Upon further heating to 360 K, about 50% of the anions or their decomposition products desorb from the surface, while cation-related fragments mostly remain on the surface. From DFT, we obtain additional information on the structure of the ordered phases and the interaction of the IL with the substrate.

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Adhikari, R., Massicot, S., Fromm, L., Talwar, T., Gezmis, E., Meusel, M.,... Steinrück, H.-P. (2023). Structure and Reactivity of the Ionic Liquid [C(1)C(1)Im][Tf2N] on Cu(111). Topics in Catalysis.


Adhikari, Rajan, et al. "Structure and Reactivity of the Ionic Liquid [C(1)C(1)Im][Tf2N] on Cu(111)." Topics in Catalysis (2023).

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