Abstract
The adsorption of propene on supported gold nanoparticles has been experimentally identified as
a reaction step in the hydro-epoxidation of propene. This new finding was made possible by applying
a detailed analysis of in situ measured XANES spectra. For this purpose, gold-on-silica catalysts were
investigated since this support is more inert and propene is not converted. Propene adsorption was
investigated by using the hydrogen oxidation as probe reaction. It was shown that co-feeding of propene
dramatically decreased the hydrogen oxidation rate. Since it has been reported in the literature that
the hydrogen oxidation occurs exclusively over gold nanoparticles, this inhibition by propene can be
attributed to adsorption of propene on the gold nanoparticles. Delta-mu analysis of the in situ XANES
spectra confirmed the adsorption of propene on the gold and the mode of adsorption was determined to
be π-bonding. Comparative experiments with ethene and propane confirmed this π-bonded adsorption,
since ethene similarly inhibited the hydrogen oxidation, while propane had only a minor effect. The direct
observation of the adsorption of propene on gold nanoparticles corroborates our recent findings, in which
we have shown that gold nanoparticles were activating propene to reactively adsorb on titania producing
a bidentate propoxy species.
| Original language | Undefined/Unknown |
|---|---|
| Pages (from-to) | 256-264 |
| Number of pages | 9 |
| Journal | Journal of Catalysis |
| Volume | 258 |
| Publication status | Published - 2008 |