空心Beta沸石的制备与表征

Preparation and characterization of hollow Beta zeolites

采用水热晶化法合成Beta沸石,再经过二次处理制备出空心结构的Beta沸石分子筛,并采用XRD、FTIR、NMR、N_2吸附-脱附、SEM和TEM等方法对空心Beta沸石分子筛试样进行表征。实验结果表明,空心Beta沸石为300 nm左右的类球状晶体,晶体内部为大空腔,外壳厚度约30 nm;在空心Beta沸石形成的过程中,晶体结构遭到部分破坏,主要是部分初级和次级结构发生变化,硅铝元素发生结构重排,比表面积、孔体积、总酸量、Br?nsted酸量和Lewis酸量有所降低。

Hollow Beta zeolites were prepared by post-processing using the Beta zeolites synthesised by hydrothermal method.Then,the hollow structure of the Beta zeolites was characterized by XRD,FTIR,NMR,N2 adsorption-desorption,SEM and TEM techniques.The results showed that the crystal size of the hollow Beta zeolites was 300 nm around and the shell thickness of the empty cavity was about 30 nm.In the formation of the hollow Beta zeolites,the crystal structure was destroyed partly with some primary and secondary structure changed and some silicon aluminum structure rearranged,resulting in decreases of the specific surface area and the pore volume to some extent,accompanied by the diminution of the amounts of the total acids,Bronsted acid and Lewis acid.