Behaviour of the resonant absorption area of a57Fe-doped Ni/C catalyst during sulfidation

Autor: Crajé, M. W. J., Volmer, W. F., de Beer, V. H. J., van der Kraan, A. M.
Zdroj: Hyperfine Interactions; December 1994, Vol. 93 Issue: 1 p1771-1775, 5p
Abstrakt: In-situ Mössbauer spectroscopy measurements down to 4.2 K were performed on a57Fe:Ni(0.5)/C catalyst after various successive sulfidation treatments. After exposure of the catalysts to the H2S/H2 gas mixture at room temperature, part of the57Fe becomes sulfidic. The rest is present as a sulfate-like intermediate species. The interaction between this intermediate species and the carbon support material is influenced by water. At temperatures below 180 K the water is rigid, at higher temperatures the water becomes mobile. This weakens the interaction with the support material, resulting in a decrease of the RAA. The interaction between the sulfidic species and the support material is not influenced by water. However, this species is not yet very well ordered; therefore, the57Fe is loosely bound. The ordering becomes better by sulfidation at higher temperatures, leading to an increase of the RAA.
Databáze: Supplemental Index
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