Synthesis of core–shell zeolitic imidazolate frameworks for enhanced CO2 capture and separation over N2: A GCMC simulation and experimental study

Abstract

Core-shell Zeolitic Imidazolate Frameworks (ZIFs), ZIF-8@ZIF-67 and ZIF-67@ZIF-8, were synthesized via seed-mediated growth at room temperature while preserving their rhombic dodecahedron morphology. These materials exhibited enhanced CO<inf>2</inf> adsorption capacity, with ZIF-67@ZIF-8 achieving a 38 % improvement over monometallic ZIF-8 at 1 bar and 0 °C. Furthermore, CO<inf>2</inf>/N<inf>2</inf> selectivity increased by 25 %, demonstrating superior separation efficiency. Grand Canonical Monte Carlo simulations confirmed that the Zn-Co interface strengthens CO<inf>2</inf> binding energy while reducing N<inf>2</inf> affinity, providing molecular-level insights into the adsorption mechanism. These findings suggest that core–shell ZIFs are promising candidates for energy-efficient CO<inf>2</inf> capture in industrial applications.