Catalytically active and hierarchically porous SAPO-11 zeolite synthesized in the presence of polyhexamethylene biguanidine

Hierarchically porous SAPO-11 zeolite (H-SAPO-11) is rationally synthesized from a starting silicoaluminophosphate gel in the presence of polyhexamethylene biguanidine as a mesoscale template. The sample is well characterized by XRD, N 2 sorption, SEM, TEM, NMR, XPS, NH 3 -TPD, and TG techniques. The results show that the sample obtained has good crystallinity, hierarchical porosity (mesopores at ca. 10   nm and macropores at ca. 50–200   nm), high BET surface area (226   m 2 /g), large pore volume (0.25   cm 3 /g), and abundant medium and strong acidic sites (0.36   mmol/g). After loading Pt (0.5   wt.%) on H-SAPO-11 by using wet impregnation method, catalytic hydroisomerization tests of n -dodecane show that the hierarchical Pt/SAPO-11 zeolite exhibits high conversion of n -dodecane and enhanced selectivity for branched products as well as reduced selectivity for cracking products, compared with conventional Pt/SAPO-11 zeolite. This phenomenon is reasonably attributed to the presence of hierarchical porosity, which is favorable for access of reactants on catalytically active sites. The improvement in catalytic performance in long-chain paraffin hydroisomerization over Pt/SAPO-11-based catalyst is of great importance for its industrial applications in the future.