Synthesis core shell SAPO-18/SAPO-34 as Methanol to olefin catalysts

A series of SAPO-18/ASPO-34 nano catalysts with hierarchical porosity were synthesized by new two stage hydrothermal method using inorganic aluminum and Si sources and different type of template (Tetraethyl ammonium hydroxide and di-isopropyl ethyl amine). The properties of core-shell SAPO-18/SAPO-34 catalyst and SAPO-34 catalyst are analyzed by XRD, NR2R-adsoption, FTIR and NHR3R-TPD. With adding SAPO-18 to SAPO-34 zeolite gel, external surface area, total pore volume, particle size of SAPO-34 decrease but crystalinity is almost constant and SAPO-5 is not appeared in XRD diffraction. Finally, their catalytic activity in methanol-to-olefin (MTO) reaction was evaluated at 425-445 °C, These core shells catalysts showed the higher performance to propylene and C4-C5 than SAPO-34 catalysts. The working lifetime in the SAPO-18/34 catalysts was remarkably more than SAPO-34. The SAPO-18/34 catalysts were regenerated perfectly.