SAPO-34 molecular sieves were synthesized by the addition of β-cyclodextrin（β-CD） as crystal growth inhibitor using metakaolin as silicon and aluminum sources. Properties of the obtained samples were characterized...SAPO-34 molecular sieves were synthesized by the addition of β-cyclodextrin（β-CD） as crystal growth inhibitor using metakaolin as silicon and aluminum sources. Properties of the obtained samples were characterized by XRD,SEM,N2adsorption–desorption,FTIR,XRF,EDX,NH293-TPD andSi MAS NMR. When β-CD was added,crystal size of the SAPO-34 crystals decreased. Variation of Si content from the crystal center to surface decreased while total Si content hardly changed.29 Si MAS NMR results showed that β-CD contributed to better Si dispersion and decreased the size of Si（4Si） patches. Moreover,the MTO（methanol-to-olefin） process was conducted to investigate the influence of β-CD on catalytic performance. The synthesized sample with molar ratio of β-CD/Al2O3 equaling 0.055 remained active for 610 min while the sample synthesized without β-CD for only 280 min,which indicates that the lifetime of catalyst synthesized with β-CD is greatly prolonged.展开更多
基金supported by the National Natural Science Foundation of China(21406247)
文摘SAPO-34 molecular sieves were synthesized by the addition of β-cyclodextrin（β-CD） as crystal growth inhibitor using metakaolin as silicon and aluminum sources. Properties of the obtained samples were characterized by XRD,SEM,N2adsorption–desorption,FTIR,XRF,EDX,NH293-TPD andSi MAS NMR. When β-CD was added,crystal size of the SAPO-34 crystals decreased. Variation of Si content from the crystal center to surface decreased while total Si content hardly changed.29 Si MAS NMR results showed that β-CD contributed to better Si dispersion and decreased the size of Si（4Si） patches. Moreover,the MTO（methanol-to-olefin） process was conducted to investigate the influence of β-CD on catalytic performance. The synthesized sample with molar ratio of β-CD/Al2O3 equaling 0.055 remained active for 610 min while the sample synthesized without β-CD for only 280 min,which indicates that the lifetime of catalyst synthesized with β-CD is greatly prolonged.
