From nanoparticles to hierarchical structures: Controlling the morphology of zeolite beta

Zeolite beta (Si/Al∼18) was synthesized from a single template reaction mixture in a one-step hydrothermal treatment. By adjusting the synthesis conditions, the formation of isolated nanocrystals or mesoporous aggregates of zeolite beta was achieved. Depending on the synthesis conditions, zeolite beta nanocrystals of approximately 20–150 nm in diameter or mesoporous aggregates of approximately 120–140 nm in diameter were prepared. The use of concentrated synthesis gels resulted in mesoporous aggregates of nanocrystals and diluted reaction mixtures resulted in isolated zeolite nanoparticles. The crystallinity of the samples determined from pXRD patterns is similar to that of commercially available micron-sized zeolite beta. The samples had surface areas of greater than 600 m2/g and mesopore volumes of 0.4–0.5 cc/g.

Zeolite beta nanocrystals can be synthesized as individual particles (left TEM image) or as a part of larger aggregates (right TEM image). By tuning the reaction parameters, such as the concentration of the precursors and the pH zeolite beta aggregates containing micropores and mesopores were synthesized.Figure optionsDownload as PowerPoint slideResearch highlights
► Zeolite beta synthesized with a Si/Al = 18.
► Single template and a one-step hydrothermal treatment used.
► Nanocrystals of 20–150 nm in diameter formed from dilute mixtures.
► Mesoporous aggregates of ∼130 nm in diameter formed from concentrated mixtures.