| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 65606 | Journal of Molecular Catalysis A: Chemical | 2014 | 9 Pages |
•BaO modification promoted the activity for propene oxidation, while sulfation inhibited it.•Propene oxidation on Pt/Al2O3 undergoes the path from acrylates to carboxylates and formates and oxidized into CO2 and H2O.•The improving effect is related to the active oxygen at Pt–Ba interface and the active enolic species formed during the reaction.•The inhibition is related to the alteration of partial Pt0 to Ptδ+, strong adsorption of propene on the catalysts surface and poisoning effect caused by intermediate CO.
BaO and SO42− modified Pt/Al2O3 catalysts were prepared by a two-step wetness incipient method. The textural properties were characterized by BET, XRD, ex situ FTIR. Propene oxidation activity under various redox ratio (S = [O2]/4.5[C3H6]) was evaluated. The oxidation process and intermediate species were studied by detailed in situ FTIR experiments including propene adsorption CO IR and propene TPO. It is observed that the addition of BaO promotes the catalytic oxidation of propene over Pt/Al2O3, while sulfation results in the deactivation of Pt/Al2O3. The good activity of Pt/BaO/Al2O3 is ascribed to the weakened propene adsorption, the formation of reactive enolic species and easy oxidation of intermediate CO by active oxygen at Pt–Ba interface. On the contrary, the strong adsorption of propene as well as the intermediate CO poisoning are proved to be the main reasons for the deactivation of Pt/SO42−/Al2O3. A general reaction scheme is proposed based on these results.
Graphical abstractReaction pathway of propene oxidation on (a) Pt/Al2O3, (b) Pt/BaO/Al2O3 and (c) Pt/SO42−/Al2O3 catalysts.Figure optionsDownload full-size imageDownload high-quality image (125 K)Download as PowerPoint slide
