Synthesis, Types, and Applications of Zeolite Capsule Catalysts

Abstract

Capsule catalysts offer a unique spatial confinement effect, which effectively minimizes byproduct formation, enhances catalyst life, and promotes tandem reactions, thus reducing energy, time, and raw material consumption. This review presents an overview of recent advances and research progress in capsule catalysts, highlighting major breakthroughs in preparation strategies over the past decade. Innovative synthesis methods are discussed based on synthesis principles, difficulty, and effectiveness, along with an analysis of growth mechanisms and the advantages and disadvantages of zeolite shells. Application status of capsule catalysts in high‐value hydrocarbon synthesis from syngas, low‐carbon alkane dehydroaromatization, and CO2 hydrogenation reactions is explored. Finally, challenges and future prospects for scientific research and industrial applications of capsule catalysts are addressed.

Recent Trends in Tailoring External Acidity in Zeolites for Catalysis

“…The precursor solution usually employed for the synthesis of the silicalite-1 layer includes water, an organic template (generally tetrapropylammonium), a silica source, e.g., tetraethyl orthosilicate (TEOS) or fumed silica, and, eventually, ethanol used as solvent to enhance the crystallization of the zeolite shell. 7 The growth of the layer of silicalite-1 is usually performed at 180 °C for 24 h. High molar H 2 O/SiO 2 ratios are always required to prevent the segregated nucleation of silicalite-1 crystals and to promote the epitaxial growth around the core.…”

An Approach towards the Conversion of Biomass Feedstocks into Biofuel Using a Zeolite Socony Mobil-5-Based Catalysts via the Hydrothermal Liquefaction Process: A Review

“…Researchers often modify zeolites using strategies like ion exchange or metal impregnation to tailor their properties, further enhancing acidity, selectivity, and stability. In summary, zeolites, as catalysts in HTL, offer a versatile platform for efficient and selective biomass conversion into biofuels, with their unique acidity, confinement effects, and morphology playing key roles in optimising catalytic performance [41].…”