【摘 要】
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Zeolites are crystalline porous materials,which have widespread applications in industry.The synthesis methods,structure and acid properties of zeolites are important factors,which influences the appl
【机 构】
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Shanghai Research Institute of Petrochemical Technology SINOPEC,201208,Shanghai,P.R.China
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Zeolites are crystalline porous materials,which have widespread applications in industry.The synthesis methods,structure and acid properties of zeolites are important factors,which influences the applications of the materials.Investigation of these factors in experiments is a heavy task,since there are too many parameters to be optimized for the synthesis,and present characterization methods are not so robust to understand the active sites in the pore.For the MTW-type zeolites as example,we investigated the synthesis prescriptions,structure and acid properties of the zeolites using periodic density functional theory with the PBE functional.The dispersion and coulomb repulsion corrections were used.We present the substitution energy for the evaluation of zeolites synthesis prescriptions.The acid properties of the zeolites were studied via the adsorption of NH3 and pyridine.Our results show that the framework and alkaline ions are favorable following the order: Al > Fe ≈ Ga > B,Li > Na ≈ K > NH4 > H for the synthesis of MTW zeolites via green routes.Alkaline ions could influence the distribution of the trivalent ions in the zeolites framework.The acid properties of the zeolites for following the order: Al-MTW > Fe-MTW ≈ Ga-MTW > B-MTW.These results agree well with the reported experiments,and more meaningful results will be reported in our future works.
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