Hydro-modulator induced defective structure and hieratical pores in UiO-66 for efficient adsorption and catalysis

Abstract: Organic linkers are typically controlled to create the micropore structure when synthesizing metal-organic frameworks (MOFs). However, developing a hierarchical pore structure is beneficial for improving the efficiency of MOFs in various applications. This study investigates a green strategy using a water modulator that competes with the terephthalic ligand to coordinate with zirconium clusters, thereby accessing open sites for hierarchical micro- and mesopores in UiO-66. Using a hydro-modulator induced the formation of a mesoporous structure and enhanced the hydrophilic properties of UiO-66-X due to the presence of hydroxyl groups. Also, model calculations using density functional theory (DFT) support the observed structural chemical geometry. The advantages of a hierarchical pore structure, increased hydrophilicity, and the presence of open sites in the robust structure of UiO-66-X led to a significant enhancement in both antibiotic adsorption and the catalytic activity of ring-opening epoxide reactions compared to the pristine microporous UiO-66. Therefore, utilizing water as a green modulator presents a simple and environmentally friendly approach to introducing hierarchical pore structures in MOFs. It offers a promising strategy for enhancing their performance across various applications. © 2024 Elsevier Ltd