Alkene oxidation on Pd(100): Why total not partial?
- Stanford Univ., Stanford, CA (United States)
Partial alkene oxidation has previously been observed on Ag(110) and Rh(111) under ultrahigh vacuum conditions. Atomic oxygen on Ag(110) reacts with alkenes through acid-base reactions or epoxidations, whereas on Rh(111) alkenes can be oxidized to ketones. On Pd(100), a neighbor to both Ag and Rh in the periodic table, we detected no partial oxidation products for coverages of adsorbed oxygen up to one oxygen atom per surface palladium atom for any of the alkenes studied, including ethylene, propene, 1-butene, and 1,3-butadiene; only total oxidation (combustion) products were observed. Strong bonding of the alkenes to Pd(100) appears to invalidate the application of gas phase acidity concepts known to apply on Ag(110), and efficient O-H bond formation on Pd(100) seems to prevent ketone formation as observed on Rh(111). Two different combustion pathways were identified, namely, direct (oxygen-activated) combustion and indirect (decomposition and oxidation) combustion.
- OSTI ID:
- 370121
- Report Number(s):
- CONF-960376--
- Country of Publication:
- United States
- Language:
- English
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