纳米ZSM-5分子筛的合成与表征

Synthesis and Characterization of Nanosized ZSM-5 Zeolite

水热法合成常规微米 ZSM- 5分子筛并使用其作为基准物 ,以中孔碳纳米管为惰性基体 ,限定空间尺寸法合成了 Si O2 /Al2 O3 =1 0 0的纳米 ZSM- 5分子筛。 X射线粉末衍射测定结果表明该合成产品具有典型的 ZSM- 5骨架结构和纳米尺寸。红外光谱显示所合成产品具有典型的 ZSM- 5型沸石分子筛的骨架振动 ,但与基准物相比较同时出现了蓝移和红移现象。透射电镜显示纯化后的碳纳米管具有 2 0— 30 nm的内径并已多处开口 ,晶粒度在 30— 6 0 nm之间。扫描电镜表明纳米沸石的存在 ,同时由于小尺寸效应该样品呈球形聚集态。该方法可用于合成不同晶粒大小的产品 ,且沸石的分离较容易。

The nanocrystalline ZSM-5 with SiO_2/Al_2O_3 ratios of 100 was successfully synthesized by hydrothermal method with mesoporous carbon nanotubes (CNTS) as the inert matrix and micrometer ZSM-5 zeolite as standard substance.X-ray powder diffraction patterns show the typical ZSM-5 structural characteristics (MFI) and nanosize.The infrared spectroscopy spectra indicate that the samples have the typical vibrations of ZSM-5 zeolite with red and blue shifts.The transmission electron microscopy images of the purified carbon nanotubes and nanosized ZEM-5 crystals after the removal of the carbon matrix suggest that clean and homogeneous carbon nanotubes have internal diameters of approximately 20—30 nm and crystal sizes in the range 30—60nm.The scanning electron microscopy photograph verifies the existing of nanosized ZSM-5.Meanwhile,the nanocrystals are aggregates of primary global particles.The method can be used to prepare crystals with different sizes by using various carbon matrix and the separation of products are easy.