[2Fp01-09] Surface Science(SS2) Chemical Property

[2Fp06] In situ observation of oxygen species on Ag(110) during ethylene epoxidation via X-ray and infrared spectroscopy

*Yu Murano¹, Ryo Toyoshima¹, Shinsuke Eguchi¹, Hiroshi Kondoh¹ (1. Graduate School of Science and Technology, Keio University)

Silver (Ag) is an established industrial catalyst to produce ethylene oxide (EO). Covalent oxygen species such as sulfate (SO₄) and carbonate (CO₃) have been proposed as the candidates of oxygen-donor species which provide their O atom to π-bond of ethylene to produce EO. In this study, we report new insights into behavior of the covalent oxygen species contributing to ethylene epoxidation on Ag(110) obtained from in situ measurements of near ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) and polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS). NAP-XP spectra clearly show that CO₃ and SO₄ species exist on the Ag(110) surface under reaction conditions. Temperature dependence of adsorption states were measured using PM-IRRAS with monitoring EO production by mass spectrometry. Correlation between the IRRAS peak behavior and EO production is presented in the talk.