Methanolic C-O bond activation on Pd(111): A coverage-dependent reaction

Journal Article · Wed Mar 25 04:00:00 EST 1992 · Journal of the American Chemical Society

DOI:https://doi.org/10.1021/ja00033a058· OSTI ID:450843

Chen, Jr-Jyan; Winograd, N ^[1]

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1. Pennsylvania State Univ., University Park, PA (United States)

The authors find that the previously reported methanolic C-O bond activation on Pd(111) to form adsorbed methyl and hydroxyl at 225 K occurs only for initial methanol coverages near 1 monolayer. At lower and higher coverages, methanol decomposes via the more traditional methoxy intermediate. Moreover, when methyl is formed, it is not observed to decompose until the temperature is raised to 400 K. This thermal behavior is quite unusual since CH{sub 3} has been observed to combine with H to desorb as CH{sub 4} below 300 K, dimerize to produce C{sub 2}H{sub 6} below 200 K, or dehydrogenate to form CH{sub 2} and H below 200 K. In addition, it is found that methyl undergoes sequential dehydrogenation as the temperature is increased to form CH{sub 2} at 400 K, CH at 500 K, and C at >500 K. The authors speculate that the coverage dependency is connected with the thermal stability of CH{sub 3} by a site-blocking mechanism, probably involving CO. 22 refs., 2 figs.

• Sponsoring Organization: USDOE
• OSTI ID: 450843
• Journal Information: Journal of the American Chemical Society, Journal Name: Journal of the American Chemical Society Journal Issue: 7 Vol. 114; ISSN JACSAT; ISSN 0002-7863
• Country of Publication: United States
• Language: English

Related Subjects

10 SYNTHETIC FUELS
40 CHEMISTRY
CATALYTIC EFFECTS
CHEMICAL ACTIVATION
DEHYDROGENATION
HETEROGENEOUS CATALYSIS
METHANOL
PALLADIUM