Enhanced catalytic behavior for methanol to lower olefins over SAPO-34 composited with ZrO2
| Autor: | Jianxin Cao, Wang Xiaodan, Fangtao Huang, Fei Liu, Le Wang |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
chemistry.chemical_classification
General Chemical Engineering 02 engineering and technology General Chemistry Microporous material 010402 general chemistry 021001 nanoscience & nanotechnology Molecular sieve 01 natural sciences Industrial and Manufacturing Engineering Hydrothermal circulation 0104 chemical sciences Catalysis chemistry.chemical_compound chemistry Chemical engineering Environmental Chemistry Methanol 0210 nano-technology Mesoporous material Selectivity Alkyl |
| Zdroj: | Chemical Engineering Journal. 380:122626 |
| ISSN: | 1385-8947 |
| DOI: | 10.1016/j.cej.2019.122626 |
| Popis: | A microporous SAPO-34 molecular sieve was tailored via a surface compositing strategy of a mesoporous t-ZrO2 with both L acid and base characteristics. A hydrothermal coating method was employed to successfully fabricate the SAPO-34/t-ZrO2 catalyst with a distinct chemical interphase, which showed excellent catalytic activity and lifetime during the conversion of methanol to lower olefins. At ambient pressure and a reaction temperature of 380 °C, the methanol conversion reached 100% and the selectivity for lower olefins was over 90%. The catalyst lifetime reached 1130 min, which was an increase of 770 min compared to using unmodified SAPO-34. By using the physically-blend catalyst t-ZrO2/SAPO-34 and the unmodified SAPO-34 as references, the MTO reaction and carbon deposit behaviors of the surface composited catalyst were determined. Via a hydrothermal coating method to modify the molecular sieve, the fabricated complex solid solution interphase effectively regulated the Si distribution on surface of SAPO-34. The SAPO-34/t-ZrO2 mainly contained synergic active centers of B acid and lesser amounts of L acid-base, as well as a micro-mesoporous system, which were crucial to decrease the carbon deposition formation rate. By studying the in situ IR and carbon deposition, it was revealed that abundant various kinds of active centers and the micro-mesoporous system in the SAPO-34/t-ZrO2 modified catalyst allowed large long-chain alkyl benzenes to form. This novel catalytic behavior effectively inhibited the cyclization and polycondensation of the carbon deposit precursors, leading to an excellent resistance to deactivation induced by carbon deposition. |
| Databáze: | OpenAIRE |
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