Spillover sites on a 19% Ni/Al sub 2 O sub 3 catalyst

Journal Article · Thu Jun 01 04:00:00 EDT 1989 · Journal of Catalysis; (USA)

DOI:https://doi.org/10.1016/0021-9517(89)90351-5· OSTI ID:6414597

Sen, B; Falconer, J L ^[1]

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1. Univ. of Colorado, Boulder (USA)

Two distinct methanation sites are clearly identified on a 19% Ni/Al{sub 2}O{sub 3} catalyst by temperature-programmed reaction (TPR) employing isotope labeling. The two sites, which are present after reduction at 975 K, are due to CO adsorption on Ni crystallites and CO and H spillover onto the Al{sub 2}O{sub 3} support. The concentration of sites on the support is 250 {mu}mol/G Al{sub 2}O{sub 3} (5 {times} 10{sup 13} molecules/cm{sup 2}), which is the same value measured for a 5.1% Ni/Al{sub 2}O{sub 3} catalyst and for a 1.0% Ru/Al{sub 2}O{sub 3} catalyst. Temperature-programmed desorption suggest that the CO and H on the Al{sub 2}O{sub 3} are in the form of a H-CO complex. The formation of this complex is an activated process, which is related to the activated adsorption of H{sub 2}. The H{sub 2} that adsorbs between 300 and 385 K is responsible for this spillover process onto the Al{sub 2}O{sub 3}. Isotope labeling and TPR were used to verify that a H-CO complex does not form on Ni/SiO{sub 2} catalysts. Carbon monoxide adsorption on Ni/SiO{sub 2} was not activated and only one methanation site was seen.

• OSTI ID: 6414597
• Journal Information: Journal of Catalysis; (USA), Journal Name: Journal of Catalysis; (USA) Vol. 117:2; ISSN 0021-9517; ISSN JCTLA
• Country of Publication: United States
• Language: English

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