Ultrasmall Zeolite L Crystals Prepared from Highly Interdispersed Alkali‐Silicate Precursors

Abstract

The preparation of nanosized zeolites is critical for applications where mass-transport limitations within microporous networks hinder their performance. Often the ability to generate ultrasmall zeolite crystals is dependent upon the use of expensive organics with limited commercial relevance. Herein, we report the generation of zeolite L crystals with uniform sizes less than 30 nm using a facile, organic-free method. Time-resolved analysis of precursor assembly and evolution during nonclassical crystallization highlights key differences among silicon sources. Our findings reveal that a homogenous dispersion of potassium ions throughout silicate precursors leads to the formation of a metastable nonporous phase, which undergoes an intercrystalline transformation to zeolite L. The generation of highly interdispersed alkali-silicate precursors is seemingly critical to enhancing the rate of nucleation and facilitating the formation of ultrasmall crystal.

Time resolved alkali silicate decondensation by sodium hydroxide solution

“…In recent decades, silicates glasses or aluminosilicates binders have been widely studied in the construction industry and other specific areas. For instance, alkali silicate has been proposed to be used as binders in the nuclear industry to immobilize and store radioactive wastes in deep geological disposals [19,20] as well as precursors to the formation of zeolites [21][22][23]. These materials are elaborated by mixing aluminosilicate mineral powders with solutions composed of a mixture of alkali silicate with sodium hydroxide.…”

Tracking the rearrangement of atomic configurations during the conversion of FAU zeolite to CHA zeolite

“…1,2 Although atomic-level understanding has been aspired to for years with zeolite synthesis, 3 previous studies have been limited owing to the nature of hydrothermal synthesis, which is a standard technique to prepare these microporous materials. The reaction is generally mediated by amorphous aluminosilicates, [4][5][6][7][8] which makes the elucidation of the formation mechanism difficult. In situ analyses of zeolite formation [9][10][11][12][13][14][15] have been conducted to capture a detailed image of zeolite synthesis.…”

Advances in the Synthesis of Ferrierite Zeolite

“…Therefore, the synthesis of aluminosilicate FER zeolite nanocrystals is one of the numerous efforts that have been made to overcome the above drawbacks. The access of smaller crystals not only shortens the diffusion paths for reagent and product molecules, but also enlarges the external surface area and thus provides more accessible acidic sites [73,[88][89][90].…”