X-Ray Absorption and Photoemission Studies of the Active Oxygen for Ethylene Epoxidation over Silver
Full article
| Общее |
Language:
Английский,
Genre:
Full article,
Status:
Published,
Source type:
Original
|
| Journal |
Catalysis Letters
ISSN: 1011-372X
, E-ISSN: 1572-879X
|
| Output data |
Year: 2001,
Volume: 74,
Number: 3-4,
Pages: 121-125
Pages count
: 5
DOI:
10.1023/A:1016666021405
|
| Tags |
Epoxidation, Ethylene, Oxygen, Silver, XANES, XPS |
| Authors |
Bukhtiyarov V.I.
1
,
Hävecker M.
2
,
Kaichev V.V.
1
,
Knop-Gericke A.
2
,
Mayer R.W.
2
,
Schlögl R.
2
|
| Affiliations |
| 1 |
Boreskov Institute of Catalysis, Lavrentieva prosp., 5, 630090 Novosibirsk, Russia
|
| 2 |
Fritz-Haber-Institut der MPG, Faradayweg 4-6, D-14195 Berlin (Dahlem), Germany
|
|
Funding (2)
|
1
|
Russian Foundation for Basic Research
|
00-15-99335
|
|
2
|
Max Planck Society
|
|
Activation of clean polycrystalline silver by a C2H4 + O2 reaction mixture has been studied by XANES, XPS, and UPS. In situ monitoring of the O K-edge XAS spectrum of the pre-treated silver surface revealed a broad signal at 10–20 eV above the threshold. The comparison of the X-ray absorption spectra with O 1s and valence band photoemission data allowed us to attribute this XAS signal to “electrophilic” oxygen (Eb(O 1s) = 530.4 eV) which is known to be active in ethylene epoxidation. The complete absence of XAS features in the photon energy range typical for π* and σ* transitions of molecular oxygen (530–535 eV) indicates both the atomic origin of the electrophilic oxygen and the absence of molecular species on the catalyst surface under the present reaction conditions.