Aqueous Synthesis of UiO‐66 Metal‐Organic Frameworks With Enhanced Crystallinity and Surface Area

Metal‐organic frameworks (MOFs) have emerged as critical and powerful materials for applications requiring a high surface area and tunable chemistries, including CO 2 capture, energy harvesting, and catalytic applications. However, despite the broad interest in MOFs, their translation from lab scale to industrial scale production is stymied due to expensive and toxic solvents such as N,N‐dimethylformamide (DMF). Thus, transitioning to green chemistry methods for MOF synthesis using inexpensive and benign solvents is imperative to translate MOFs for real‐world applications. Unfortunately, in the vast majority of cases, the use of such benign solvents leads to MOFs with significantly inferior properties, including crystallinity and surface area. Here, a water‐based method is employed to produce UiO‐66(Zr) MOFs with high crystallinity and surface area. This method is enabled by varying NaOH concentration to control both the deprotonation of terephthalic acid and pH, facilitating efficient cluster–ligand coordination at 65 °C and atmospheric pressure. An industrially recyclable solvent such as ethanol is used in the purification process, enhancing scalability and sustainability. In contrast to prior reports, this method yielded highly crystalline MOF particles with a high surface area of 741 m 2 g −1 , demonstrating the effectiveness of aqueous synthesis and green purification for producing high‐quality UiO‐66 materials.