Hierarchical ZSM-5 zeolite was hydrothermally synthesized by a novel silicone quaternary ammonium salt surfactant as a mesopore director.The crystallinity and the morphology of sample were characterized by X-ray diffr...Hierarchical ZSM-5 zeolite was hydrothermally synthesized by a novel silicone quaternary ammonium salt surfactant as a mesopore director.The crystallinity and the morphology of sample were characterized by X-ray diffraction(XRD),field-emission scanning electron microscope(FE-SEM),and transmission electronic microscope(TEM).Results indicated that the prepared ZSM-5 zeolites had good crystallinity,ellipsoid structure morphology and rough surface.Moreover,the pore size was enlarged to about 4 nm measured by nitrogen sorption,which indicated positive function of the synthesized template.展开更多
The pore sizes of traditional zeolites are in the range of0. 3-1. 5 nm,which strongly hinder the diffusion of large reactant and product molecules within the zeolite pores. To compensate for it,we tried to create meso...The pore sizes of traditional zeolites are in the range of0. 3-1. 5 nm,which strongly hinder the diffusion of large reactant and product molecules within the zeolite pores. To compensate for it,we tried to create mesopores in traditional microporous zeolites and retain all advantages of microporous zeolites. Mesoporous Zeolite Socony Mobile-Five( ZSM-5) zeolite was synthesized by a new double ester base long carbon chains organosilane quaternary ammonium salt as the soft template agent in hydrothermal method.The structure of the acquired zeolite crystals was confirmed by fieldemission scanning electron microscopy( FE-SEM), transmission electron microscopy( TEM), nitrogen adsorption-desorption measurements and X-ray diffraction( XRD),which indicated that their structure had the same characteristics as traditional ZSM-5 zeolites. Compared with traditional ZSM-5 zeolite,there were 4 nm and 15 nm mesopores in the crystal. The prepared hierarchical porous ZSM-5 zeolite was expected to be effective catalytic materials for chemical reactions involving large molecules.展开更多
The hierarchical mesoporous Zn/ZSM-5 zeolite catalyst was prepared by NaOH treatment and Zn impregnation, and its application in the conversion of methanol to gasoline （MTG） was studied. N2 adsorption-desorption res...The hierarchical mesoporous Zn/ZSM-5 zeolite catalyst was prepared by NaOH treatment and Zn impregnation, and its application in the conversion of methanol to gasoline （MTG） was studied. N2 adsorption-desorption results showed that the mesopores with sizes of 2-20 nm in HZ5/0.3AT was formed by 0.3 M NaOH alkali treatment. The zeolite samples after modification were also characterized by XRF, AAS, XRD, SEM and NH3-TPD methods. Zn impregnated catalyst Zn/HZ5/0.3AT exhibited dramatic improvements in catalytic lifetime and liquid hydrocarbons yield. The selectivity of aromatic hydrocarbons was also improved after Zn impregnation. It is suggested that the mesopores of Zn/HZ5/0.3AT enhanced the synergetic effect of Zn species and acid sites and the capability to coke tolerance, which were confirmed by the results of catalytic test and TGA analysis, respectively.展开更多
基金National Natural Science Foundation of China(No.21676053)
文摘Hierarchical ZSM-5 zeolite was hydrothermally synthesized by a novel silicone quaternary ammonium salt surfactant as a mesopore director.The crystallinity and the morphology of sample were characterized by X-ray diffraction(XRD),field-emission scanning electron microscope(FE-SEM),and transmission electronic microscope(TEM).Results indicated that the prepared ZSM-5 zeolites had good crystallinity,ellipsoid structure morphology and rough surface.Moreover,the pore size was enlarged to about 4 nm measured by nitrogen sorption,which indicated positive function of the synthesized template.
基金National Natural Science Foundation of China(No.21676053)
文摘The pore sizes of traditional zeolites are in the range of0. 3-1. 5 nm,which strongly hinder the diffusion of large reactant and product molecules within the zeolite pores. To compensate for it,we tried to create mesopores in traditional microporous zeolites and retain all advantages of microporous zeolites. Mesoporous Zeolite Socony Mobile-Five( ZSM-5) zeolite was synthesized by a new double ester base long carbon chains organosilane quaternary ammonium salt as the soft template agent in hydrothermal method.The structure of the acquired zeolite crystals was confirmed by fieldemission scanning electron microscopy( FE-SEM), transmission electron microscopy( TEM), nitrogen adsorption-desorption measurements and X-ray diffraction( XRD),which indicated that their structure had the same characteristics as traditional ZSM-5 zeolites. Compared with traditional ZSM-5 zeolite,there were 4 nm and 15 nm mesopores in the crystal. The prepared hierarchical porous ZSM-5 zeolite was expected to be effective catalytic materials for chemical reactions involving large molecules.
基金Key Research and Development Plan of Shaanxi Province(2023-YBGY-290)Research Project of Shaanxi Yanchang Petroleum(Group)Co.,Ltd.(No.ycsy2023ky-B-81)。
基金supported by the Fundamental Research Funds for the Central Universities, HUST (No. Z2009008)the National Natural Science Foundation of China (No. 20973068)
文摘The hierarchical mesoporous Zn/ZSM-5 zeolite catalyst was prepared by NaOH treatment and Zn impregnation, and its application in the conversion of methanol to gasoline （MTG） was studied. N2 adsorption-desorption results showed that the mesopores with sizes of 2-20 nm in HZ5/0.3AT was formed by 0.3 M NaOH alkali treatment. The zeolite samples after modification were also characterized by XRF, AAS, XRD, SEM and NH3-TPD methods. Zn impregnated catalyst Zn/HZ5/0.3AT exhibited dramatic improvements in catalytic lifetime and liquid hydrocarbons yield. The selectivity of aromatic hydrocarbons was also improved after Zn impregnation. It is suggested that the mesopores of Zn/HZ5/0.3AT enhanced the synergetic effect of Zn species and acid sites and the capability to coke tolerance, which were confirmed by the results of catalytic test and TGA analysis, respectively.
