Engineering Hierarchical Zeolites: Mechanistic Insights, Predictive Framework, and Deployment Pathways

Hierarchical zeolites, composed of microporous frameworks integrated with secondary mesoporosity that mitigate diffusion limitations and improve accessibility to active catalytic sites. The presence of mesopores enhances diffusion, facilitates reactant access, and improves resistance to deactivation, leading to superior performance in CO₂ capture, hydrocarbon separation, catalytic cracking, and biomass conversion. Numerous synthesis strategies have been developed, including hard and soft templating, desilication, one-pot crystallization, and 3D printing. Despite these advances, a clear framework connecting structural features to functional outcomes remains underdeveloped. This review examines diffusion mechanisms in porous media and evaluates how key structural descriptors such as mesopore size, pore connectivity, micropore volume, and external surface area influence adsorption, catalytic activity, and long-term material stability. Based on this analysis, we propose a structure-function framework that enables reproducible, semi-quantitative comparisons across studies. This review also discusses emerging research directions such as machine learning-guided synthesis, operando monitoring techniques, and modular integration approaches. Together, these insights pave the way for the development of scalable, adaptable chemical systems and support the rational design of next-generation hierarchical zeolites for industrial applications.