Influence of adsorbed CH sub 3 O on CO desorption from Ni/Al sub 2 O sub 3

Journal Article · Fri Jan 31 23:00:00 EST 1992 · Journal of Catalysis; (United States)

DOI:https://doi.org/10.1016/0021-9517(92)90258-J· OSTI ID:7202842

Flesner, R L; Falconer, J L ^[1]

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1. Univ. of Colorado, Boulder (United States)

The desorption rate of CO from the Ni surface of a 5.1% Ni/Al{sub 2}O{sub 3} catalyst was significantly increased by the presence of CH{sub 3}O on the support. The CH{sub 3}O was formed by CO and H{sub 2} coadsorption at 385 K. Reverse spillover of CH{sub 3}O, as CO desorbed, maintained the Ni surface at a high coverage of CO and H{sub 2}. This increased the rate of CO desorption because of the repulsive interactions present between CO molecules on Ni at high coverages and because readsorption on Ni was decreased. These studies show that CH{sub 3}O must undergo reverse spillover onto the Ni surface in order to decompose. Decomposition directly on the Al{sub 2}O{sub 3} surface does not occur at these temperatures. Carbon isotope labeling and temperature-programmed desorption were used to study this process. For hydrogen isotope labeling, a kinetic isotope effect for CH{sub 3}O decomposition indicated that C-H bond breaking or surface diffusion limited CH{sub 3}O decomposition. Oxygen isotope labeling showed that the carbon-oxygen bond did not break upon the formation or decomposition of CH{sub 3}O.

• OSTI ID: 7202842
• Journal Information: Journal of Catalysis; (United States), Journal Name: Journal of Catalysis; (United States) Vol. 133:2; ISSN 0021-9517; ISSN JCTLA
• Country of Publication: United States
• Language: English

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