Dresden 2020 – scientific programme
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O: Fachverband Oberflächenphysik
O 108: Electron-Driven Processes at Surfaces and Interfaces
O 108.8: Talk
Thursday, March 19, 2020, 16:45–17:00, TRE Ma
Superoxide formation near DMSO/Cu(111) interfaces — •Angelika Demling1, Sarah B. King2, and Julia Stähler1 — 1Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14169 Berlin — 2Department of Chemistry and James Franck Institute, University of Chicago, 929 E 57th St Chicago, IL 60637
DMSO is a common non-aqueous solvent with the potential to be used in lithium-oxygen batteries due to its ability to catalyze the superoxide formation [1]. In this study we investigate the electron dynamics in DMSO films on Cu(111) using time- and angle-resolved two-photon photoemission and disentangle the individual steps of charge transfer leading to superoxide formation:
Electrons are injected from the metal to the DMSO, where they form small polarons on sub-picosecond time scales. The subsequent trapping extends the electronic lifetimes to several seconds [2]. Co-adsorption of molecular oxygen quenches the trapped electron signal and leads to the appearance of an occupied state whose binding energy is in good agreement with electrochemical data of superoxide [3].
These results may contribute to a basic understanding of charge transfer processes in novel battery systems.
[1] K. M. Abraham, J. Electrochem. 162, A3021, (2015)
[2] S. B. King et al., J. Chem. Phys., 150, 041702 (2019)
[3] D. T. Sawyer et al., J. Electroanal. Chem. 12, 90 (1966)