Improvement of Lifetime Using Transition Metal-Incorporated SAPO-34 Catalysts in Conversion of Dimethyl Ether to Light Olefins
Transition metal (Mn, Fe, or Ni) incorporated SAPO-34 (MeAPSO-34) nanocatalysts were synthesized using a hydrothermal method to improve the catalytic lifetime in the conversion of dimethyl ether to light olefins (DTO). The structures of the synth...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Hindawi Limited
2013-01-01
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| Series: | Journal of Nanomaterials |
| Online Access: | http://dx.doi.org/10.1155/2013/679758 |
| Summary: | Transition metal (Mn, Fe, or Ni) incorporated SAPO-34 (MeAPSO-34)
nanocatalysts were synthesized using a hydrothermal method to improve the catalytic
lifetime in the conversion of dimethyl ether to light olefins (DTO). The structures of the
synthesized catalysts were characterized using several methods including XRD, SEM, BET,
29Si-MAS NMR, and NH3-TPD techniques. Although the structure
of the MeAPSO-34 catalysts was similar to that of the SAPO-34 catalyst, the amount of weak
acid sites in all MeAPSO-34 catalysts was markedly increased and accompanied by differences
in crystallinity and structural arrangement. The amount of weak acid sites decreased in
the following order: NiAPSO-34 > FeAPSO-34 > MnAPSO-34 > SAPO-34
catalyst. The MeAPSO-34 catalysts, when used in the DTO reaction, maintained DME
conversion above 90% for a longer time than the SAPO-34 catalyst, while also maintaining
the total selectivity above 95% for light olefins. In addition, the NiAPSO-34 catalyst showed
the longest catalytic lifetime; the lifetime was extended approximately 2-fold relative to the
SAPO-34 catalyst. Therefore, the increase in the catalytic lifetime is related to the amount
of weak acidic sites, and these sites are increased in number by incorporating transition metals into the SAPO-34 catalyst. |
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| ISSN: | 1687-4110 1687-4129 |