Selective oxidation of propylene to acrolein over silver-promoted hexagonal molybdates and derivative Ag/Ag2Mo4O13/α-MoO3 composites
| Autor: | Wenjie Shen, Na Ta, Andreas Goldbach, Qingting Zhang |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
010405 organic chemistry
Process Chemistry and Technology Acrolein 010402 general chemistry 01 natural sciences Catalysis 0104 chemical sciences chemistry.chemical_compound chemistry Orthorhombic crystal system Partial oxidation Acrylonitrile Composite material Selectivity Derivative (chemistry) Oxygenate |
| Zdroj: | Applied Catalysis A: General. 623:118275 |
| ISSN: | 0926-860X |
| DOI: | 10.1016/j.apcata.2021.118275 |
| Popis: | Hexagonal molybdates (h-MoO3) include abundant Mo vacancies that are charge-compensated by cations residing within one-dimensional channels. Hence, they present an intriguing structural motif for Mo catalysis which has been hardly explored for selective oxidation of olefins. We discovered that NH4+ and Ag+-exchanged h-MoO3 display surprisingly varied behavior during propylene oxidation. Acrolein and acrylonitrile are the main partial oxidation products with the latter forming due to NH4+ consumption. The catalytic activity more than doubles upon introduction of Ag+ which also enhances selectivity for the main products up to ∼60 %. Unexpectedly, the hexagonal frameworks transform into orthorhombic α-MoO3 40−60 °C below their reported stability limits already. In addition, Ag2Mo4O13 and Ag nanoparticles segregate in case of Ag+-containing h-MoO3 frameworks. The resulting Ag/Ag2Mo4O13/α-MoO3 composites catalyze propylene conversion into acrolein with even higher selectivity (∼80 %). Detailed analyses indicate that Ag2Mo4O13 drives formation of this oxygenate over these composites. |
| Databáze: | OpenAIRE |
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