Effect of seed on synthesis of binder-free mordenite for dimethyl ether carbonylation

A series of binder-free mordenite (MOR) zeolites were successfully prepared by hydrothermal conversion of shaped precursors containing aluminosilicate and MOR seeds. In the synthesis of seed crystals, hexadecyltrimethylammonium bromide (CTAB) was used as a crystal growth inhibitor as well as a pore filler to adjust the morphology and introduce mesoporous pores. As a result, large aggregates, assembled nanosheets, and flowers-like MOR were successfully synthesized with these MOR seeds. The effect of seed morphology on the performance of the binder-free MOR was studied by scanning electron microscopy (SEM), N2 adsorption-desorption, and NH3-TPD characterization techniques. It was found that the mesopore volume of formed MOR was positively correlated with those of the seeds. The synthesized binder-free MOR showed high activity (0.28 g methyl acetate gcat-1 h-1), 100% selectivity, and high stability in dimethyl ether (DME) carbonylation to methyl acetate, which can be attributed to the larger surface area and more mesopores. The synthesis of MOR nano-assemblies via this cost-effective strategy has a wide range of potential applications.