EXAFS (extended x-ray absorption fine structure) and IR study of the CO-adsorption-induced morphology change in Ru catalysts

Journal Article · Wed Oct 24 04:00:00 EDT 1990 · Journal of the American Chemical Society; (USA)

DOI:https://doi.org/10.1021/ja00178a006· OSTI ID:6133036

Mizushima, Takanori; Tohji, Kazuyuki; Udagawa, Yasuo ^[1]; Ueno, Akifumi ^[2]

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1. Institute for Molecular Science, Aichi (Japan)
2. Toyohashi Univ. of Technology, Aichi (Japan)

EXAFS (extended x-ray absorption fine structure) and IR studies were performed on Ru catalysts supported on {gamma}-Al{sub 2}O{sub 3}, MgO, SiO{sub 2}, and TiO{sub 2} to elucidate the mechanism of the CO adsorption-induced disruption of metal clusters. EXAFS results show that after reduction, Ru atoms exist on all supports as small metal clusters, but the particle sizes and metal-support interactions vary with the support. CO adsorption onto Ru/{gamma}-Al{sub 2}O{sub 3} and Ru/MgO led to the disruption of Ru-Ru bonds. By comparing with IR spectroscopic observations it is concluded that new species like O-Ru-CO and O-Ru-(CO){sub 2} on {gamma}-Al{sub 2}O{sub 3} and O{sub n}-Ru-CO and (O{sub n}-Ru){sub 2}-CO (n = 3,4) on MgO are formed after CO admission. On the other hand, no evidence of disruption of Ru clusters by CO adsorption was obtained in Ru/SiO{sub 2} and Ru/TiO{sub 2}. The IR study showed, contrary to previously proposed models, that no H{sub 2} evolution takes place during the CO adsorption-induced disruption. A new reaction scheme that is consistent with their observations is presented.

• OSTI ID: 6133036
• Journal Information: Journal of the American Chemical Society; (USA), Journal Name: Journal of the American Chemical Society; (USA) Vol. 112:22; ISSN 0002-7863; ISSN JACSA
• Country of Publication: United States
• Language: English

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