Abstract
We have performed the first "high-pressure" X-ray photoelectron spectroscopy (XPS) study on the palladium, hydrogen, and olefin (trans-2-pentene) system to gain better insight into the hydrogenation reaction. We report here data collected with the use of a Pd(111) single crystal and a polycrystalline foil. Hydrogenation was observed on polycrystalline foil (RT and 373 K) but not on Pd(111) single crystal, as revealed by on-line mass spectrometry. We observed the reaction in the presence of a huge amount of carbon (up to 73%) in the information depth of XPS. Mainly graphite was present on Pd(111), whereas other components, C-H and C-Pd, were also formed on the foil to a much greater extent. C-Pd characterizes a carbon species in the interaction with palladium, whereas C-H represents hydrogenated carbon, including chemisorbed species. The d-band of the foil showed a remarkable upshift toward EFERMI compared with Pd(111). We concluded that the differences found in the valence and the C1s region are indicators of different electronic structures that contribute to the variation in activity. The palladium foil lost its activity at an elevated temperature (523 K), most probably because of desorption of hydrogen. From additional UPS measurements, we concluded that trans-2-pentene is hydrogenated in σ-bonded chemisorption modus, at least in UHV conditions.
| Original language | English |
|---|---|
| Pages (from-to) | 195-203 |
| Number of pages | 9 |
| Journal | Journal of Catalysis |
| Volume | 230 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - 15 Feb 2005 |
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Keywords
- Carbonaceous deposits
- d-band
- High-pressure XPS
- Hydrogenation
- Palladium
- UPS
ASJC Scopus subject areas
- Catalysis
- Physical and Theoretical Chemistry
Cite this
High-pressure X-ray photoelectron spectroscopy of palladium model hydrogenation catalysts. Part 2 : Hydrogenation of trans-2-pentene on palladium. / Teschner, D.; Pestryakov, A.; Kleimenov, E.; Hävecker, M.; Bluhm, H.; Sauer, H.; Knop-Gericke, A.; Schlögl, R.
In: Journal of Catalysis, Vol. 230, No. 1, 15.02.2005, p. 195-203.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - High-pressure X-ray photoelectron spectroscopy of palladium model hydrogenation catalysts. Part 2
T2 - Hydrogenation of trans-2-pentene on palladium
AU - Teschner, D.
AU - Pestryakov, A.
AU - Kleimenov, E.
AU - Hävecker, M.
AU - Bluhm, H.
AU - Sauer, H.
AU - Knop-Gericke, A.
AU - Schlögl, R.
PY - 2005/2/15
Y1 - 2005/2/15
N2 - We have performed the first "high-pressure" X-ray photoelectron spectroscopy (XPS) study on the palladium, hydrogen, and olefin (trans-2-pentene) system to gain better insight into the hydrogenation reaction. We report here data collected with the use of a Pd(111) single crystal and a polycrystalline foil. Hydrogenation was observed on polycrystalline foil (RT and 373 K) but not on Pd(111) single crystal, as revealed by on-line mass spectrometry. We observed the reaction in the presence of a huge amount of carbon (up to 73%) in the information depth of XPS. Mainly graphite was present on Pd(111), whereas other components, C-H and C-Pd, were also formed on the foil to a much greater extent. C-Pd characterizes a carbon species in the interaction with palladium, whereas C-H represents hydrogenated carbon, including chemisorbed species. The d-band of the foil showed a remarkable upshift toward EFERMI compared with Pd(111). We concluded that the differences found in the valence and the C1s region are indicators of different electronic structures that contribute to the variation in activity. The palladium foil lost its activity at an elevated temperature (523 K), most probably because of desorption of hydrogen. From additional UPS measurements, we concluded that trans-2-pentene is hydrogenated in σ-bonded chemisorption modus, at least in UHV conditions.
AB - We have performed the first "high-pressure" X-ray photoelectron spectroscopy (XPS) study on the palladium, hydrogen, and olefin (trans-2-pentene) system to gain better insight into the hydrogenation reaction. We report here data collected with the use of a Pd(111) single crystal and a polycrystalline foil. Hydrogenation was observed on polycrystalline foil (RT and 373 K) but not on Pd(111) single crystal, as revealed by on-line mass spectrometry. We observed the reaction in the presence of a huge amount of carbon (up to 73%) in the information depth of XPS. Mainly graphite was present on Pd(111), whereas other components, C-H and C-Pd, were also formed on the foil to a much greater extent. C-Pd characterizes a carbon species in the interaction with palladium, whereas C-H represents hydrogenated carbon, including chemisorbed species. The d-band of the foil showed a remarkable upshift toward EFERMI compared with Pd(111). We concluded that the differences found in the valence and the C1s region are indicators of different electronic structures that contribute to the variation in activity. The palladium foil lost its activity at an elevated temperature (523 K), most probably because of desorption of hydrogen. From additional UPS measurements, we concluded that trans-2-pentene is hydrogenated in σ-bonded chemisorption modus, at least in UHV conditions.
KW - Carbonaceous deposits
KW - d-band
KW - High-pressure XPS
KW - Hydrogenation
KW - Palladium
KW - UPS
UR - http://www.scopus.com/inward/record.url?scp=13644274628&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=13644274628&partnerID=8YFLogxK
U2 - 10.1016/j.jcat.2004.11.035
DO - 10.1016/j.jcat.2004.11.035
M3 - Article
VL - 230
SP - 195
EP - 203
JO - Journal of Catalysis
JF - Journal of Catalysis
SN - 0021-9517
IS - 1
ER -