Accelerated and scalable synthesis of UiO-66(Zr) with the assistance of inorganic salts under solvent-free conditions

Abstract

UiO-66(Zr) as a member of metal–organic frameworks (MOFs) is an attractive porous material mainly because of its good structural stability and abundant metal Zr centers. Therefore, the accelerated and scalable synthesis of UiO-66(Zr) is of practical importance under solvent-free conditions. In this work, we report that such a synthesis has been successfully realized with the assistance of inorganic salts. During the synthesis, the influence of some parameters including the addition amount of inorganic salt, crystallization temperature and time, and the type of inorganic salt was investigated in detail. The characterization results reveal that UiO-66(Zr) with a large surface area (969 m² g⁻¹) and high yield (∼92%) can be obtained with the aid of NaCl (in a molar ratio of Zr/Na = 4) in a crystalline time of 3 h at 130 °C. What's more, 5.7 g UiO-66(Zr) was produced in a 15 mL autoclave, which is 100 times higher than that (below 50 mg) obtained by a solvothermal method. This result suggests that the synthetic process is conducive to large-scale production. In addition, the approach may be also extended to prepare functionalized UiO-66(Zr) materials like nitro- and amino-functionalized UiO-66(Zr).