Details

Autor(en) / Beteiligte

• Böcklein, S.
• Günther, S.
• Reichelt, R.
• Wyrwich, R.
• Joas, M.
• Hettstedt, C.
• Ehrensperger, M.
• Sicklinger, J.
• Wintterlin, J.

Titel

Detection and quantification of steady-state ethylene oxide formation over an Ag(111) single crystal

Ist Teil von

• Journal of catalysis, 2013-03, Vol.299, p.129-136

Ort / Verlag

Amsterdam: Elsevier Inc

Erscheinungsjahr

2013

Quelle

ScienceDirect

Beschreibungen/Notizen

• Detection of steady-state ethylene oxide formation on Ag single crystals is a major experimental problem because of the low reaction probability of ethylene and cross-sensitivities in the mass spectra. It is shown that with carefully chosen parameters and by periodic operation even trace amounts of ethylene oxide can be detected in a flow reactor. [Display omitted] ► Ethylene oxide was formed by catalytic reaction on an Ag(111) single crystal. ► Cross-sensitivities with other compounds in the mass spectra were essential. ► By periodic operation of the reactor, a background signal was subtracted. ► Even trace amounts of ethylene oxide could be quantitatively determined. Extensive experiments with a flow reactor were performed to reliably detect the steady-state catalytic formation of ethylene oxide from ethylene and oxygen on an Ag(111) single crystal. For single crystals with their small surfaces, this had been a major experimental problem because of the low reaction probability of ethylene and cross-sensitivities in the mass spectra. Using 16O2 ethylene oxide could be detected on mass fragment m/z=43, using 18O2 on m/z=31 and m/z=45, but strong time-dependent background signals had to be subtracted. This was achieved by periodic temperature changes of the reactor. After proper inclusion of all effects, a mole fraction of ethylene oxide of only 3×10−5 with respect to the reaction gas mixture, which was unequivocally produced by catalysis on the Ag sample, could be determined with a signal-to-noise ratio of more than one order of magnitude above the detection limit.