Capturing Ultrasmall EMT Zeolite from Template-Free Systems

Abstract

Controlling Zeolite Nucleation Small zeolite crystals are of increasing interest as catalysts and for membrane separations because they allow the high selectivity of their cages to be exploited while minimizing the kinetic limitations caused by diffusion. Ng et al. (p. 70 , published online 8 December) synthesized ultrasmall crystals (6 to 15 nanometers) of the EMT zeolite, which has a low framework density and good catalytic properties for hydrocarbon “cracking” (conversion of a large hydrocarbon to smaller ones). The synthesis of EMT has normally required expensive organic templates that limit its industrial use. Careful control of the synthesis conditions, such as ratios of reactants and short bursts of microwave heating, allowed small EMT crystals to nucleate and avoid formation of zeolites with closely related structures.