Deciphering the Association Between Metal Sites and CO ₂ Adsorption in Zeolites: Tracking, Characterization, and Regulation

The environmental hazards caused by fierce global climate change have driven the search for new routes to mitigate increasing CO₂ emissions. Specifically, adsorption is highlighted herein for its great industrialization potential. Among the prevalent carbon capture materials, zeolites are highly favored due to their high capacity, selectivity, and robustness. While the effects of pore size, composition, morphology, and particle size of zeolites are commonly emphasized for CO₂ adsorption, the influences of active site (normally metal cations) distribution are frequently neglected. In this review, the spatial distributions of different metal cations in diverse zeolites, from small- to large-pore ones, are first summarized and then associated with their CO₂ adsorption properties. Accordingly, the targeted modification strategies for adjusting metal cation position and distribution in zeolites are introduced, such as one-pot anchoring of heteroatoms into the zeolite windows. Thereafter, the typical and advanced characterization methods are elucidated to reveal the fine structure in zeolites as well as the site-adsorption relationships. Finally, a comprehensive summary and outlook for future spotlights in carbon capture field are provided, including the application of computational chemistry and artificial intelligence-assisted methodologies in determining active sites and adsorption mechanism, along with the potential solutions for the challenge of water vapor competition in zeolites.