Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
O: Fachverband Oberflächenphysik
O 9: Surface Reactions
O 9.1: Vortrag
Montag, 17. März 2025, 10:30–10:45, H25
Co2 reduction by solvated electrons at the NH3/Cu(111) interface. — •Maya Heine, Lukas Gierster, and Julia Stähler — Humboldt-Universität zu Berlin, Institut für Chemie
Understanding CO2 reactivity is crucial; the amount of CO2 in the atmosphere continues to rise with no imminent peak in fossil emissions in sight [1]. Previously, solvated electrons (es) have been suggested to activate CO2 , e.g. by forming surface bound CO2− radicals [2]. With time-resolved two-photon photoemission and the amorphous NH3/Cu(111) interface, we can study the energetics and dynamics of es on femtosecond timescales [3]. Here, the electrons are localised at the surface and their lifetime depends exponentially on NH3 coverage. On an ultrafast timescale, we can now use es to decipher the fundamental rate and steps of CO2 activation. We observe a systematic decrease in the es lifetime as CO2 is added and conclude that CO2 opens a new decay channel for es. Further, increases in the work function serve as indicators of possible reactions: electron attachment to CO2 or activated CO2− which has a dipole moment. For thick NH3 films we see a much larger work function increase and bleaching of es. This suggests that the film thickness controls the lifetime of charged reaction intermediates and thus the reaction pathway. Moreover, we show that es attachment to CO2 occurs on a 10s of ps timescale.
[1] Friedlingstein et al. ESDD (2024)
[2] Hu et al. Nat. Commun, 14, 4767 (2023)
[3] Stähler et al. Chem. Sci. 2, 5, 907 (2011)
Keywords: ultrafast; solvated electrons; photoemissions; carbon dioxide; reactivity