Flowerlike hierarchical SAPO-5 molecular sieve composed of loosely aggregating uniformly primary nano-rods-like AFI crystals

Abstract Flowerlike hierarchical SAPO-5 molecular sieve was fabricated by a hydrothermally dynamic crystallization route using tetrapropyl-ammoniuhydroxide as a single structure-directing agent. The hierarchical SAPO-5 reveals high crystallinity, and large external surface areas validated by the XRD and N2 adsorption-desorption. SEM and TEM indicate that the flowerlike hierarchical SAPO-5 is composed of loosely stacked primary nanorods with average diameter of 20 nm. FT-IR and EDS analyses show that as increasing crystallization time, more and more Si species are incorporated into the AFI crystals. Moreover, it is found that a dynamic crystallization condition is very mandatory toward the synthesis of a novel-flowerlike SAPO-5.