Insights into the Electronic Structure of the Oxygen Species Active in Alkene Epoxidation on Silver

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• 作者：Travis E. Jones ; Tulio C. R. Rocha ; Axel Knop-Gericke ; Catherine Stampfl ; Robert Schl枚gl ; Simone Piccinin
• 刊名：ACS Catalysis
• 出版年：2015
• 出版时间：October 2, 2015
• 年：2015
• 卷：5
• 期：10
• 页码：5846-5850
• 全文大小：326K
• ISSN：2155-5435

文摘

Extensive density functional theory calculations of the O_1s binding energies, adsorption energies, and the experimentally measured in situ X-ray photoelectron spectra of oxygen on silver are reported in an effort to clarify which species are present during ethylene epoxidation. We find that the O_1s binding energy of an oxygen adatom increases near linearly with its adsorption energy due to the ionic nature of the Ag/O interaction. Thus, contrary to widespread assignments, a weakly bound oxygen adatom does not account for the electrophilic species with an O_1s binding energy of 530 eV that is thought to be active in ethylene epoxidation. Instead, we show that the only species with O_1s binding energies near 530 eV are covalently bound, which we find in our calculations, for example, when hydrogen or carbon are present.