Ultrahigh mechanically stable hierarchical mordenite zeolite monolith: Direct binder-/template-free hydrothermal synthesis

Abstract

Micro-macroporous hierarchical mordenite (MOR topology) zeolitic monoliths with ultrahigh mechanical stability (crushing strength: 38MPa) were directly prepared by the one-pot hydrothermal synthesis involving an unconventional acidic hydrolysis route. The obtained monolith exhibited highly crystallized MOR structure with the surface area of 388m2g−1 and pore volume of 0.2cm3g−1, same as its powder analog. Moreover, it is the first example of binder-free hierarchical zeolites with the high mechanical strength comparable to industrially available binder-shaped counterparts. The micro-shape of primary particles and macro-shape of monoliths could be controlled by varying the elemental synthetic conditions. The synthesis is an efficient, sustainable and environmentally friendly approach because it avoids the employment of sacrificial templates, binders and high-temperature calcination, not only saving energy and time, but also inhibiting waste release. Also importantly, the MOR monolith could be directly used as the shaped catalyst without additional post-mold treatments. Catalytic tests in solvent-free Friedel–Crafts benzylation reaction of benzene with benzyl alcohol showed that the MOR monolith was much more active than its powder and binder-shaped control catalysts.