Synthesis of hierarchal SAPO-34 nano catalyst with dry gel conversion method in the presence of carbon nanotubes as a hard template.

In this study, the silicoaluminophosphate (SAPO) particles were synthesized based on dry gel conversion method using diethyl amine (DEA) as an organic structure directing agent (SDA). Transport pores were introduced into the crystalline structure of the catalyst using carbon nanotubes (CNT) as a hard template. The significance of molar ratio of CNT in the starting gel and the other synthesis parameters such as crystallization time, gel drying temperature and water content added in the crystallization stage, on crystallinity of SAPO-34, crystal phase, particle size and morphology were studied. The products were characterized by XRD, SEM, TEM, BET and EDX. D-optimal experimental design with four numeric factors including gel drying temperature, crystallization time, water/dry gel mass ratio and mole of CNT in the precursor gel each at three levels was implemented to optimize the experimental parameters by analysis of variance (ANOVA). The Fischer test results showed that, all the parameters have significant effect on the crystallinity of the synthesized samples.