Big World in the Small Space: Constructing Hollow Zeolite Microspheres Using a Sustainable Template

Hollow zeolite microspheres have attracted considerable interest due to their unique properties and great potential applications. In this work, we report a simple and cost-effective approach for constructing hollow zeolite microspheres based on a biomass-derived template, i.e., carboxymethylcellulose sodium (CMC). As an example, a hollow ZSM-5 microsphere with a hollow core smaller than 1 μm in diameter and a complete crystal shell is synthesized. This approach overcomes most of the limitations associated with the existing methods, such as complex operations and costly spherical templates. By studying the growth process in detail, a possible formation mechanism is proposed. The crystallization of the hollow zeolite microsphere is through a “surface to core” process, in which the interaction between the CMC and the zeolite gel and the decomposition of the polymer network play the critical roles.