O-Th-Seg-16 The Promotion Effect in Heterogeneous Catalysis: the Role of Cl on the Epoxidation of Ethylene over Ag

Thursday, June 6, 2013: 4:00 PM
Segell (Galt House Hotel)
Tulio Rocha, Axel Knop-Gericke and Robert Schlögl, Fritz Haber Institute of the Max Planck Society, Germany.
We report a direct in situ observation of a promoter modifying the active sites of a heterogeneous catalyst by near ambient pressure X-ray photoelectron spectroscopy. For Ag catalysts under ethylene epoxidation, the increase in selectivity promoted by Cl arises from changes in the balance between electrophilic and nucleophilic oxygen species.

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