Facile synthesis of MOF-177 by a sonochemical method using 1-methyl-2-pyrrolidinone as a solvent

Abstract

High quality MOF-177 crystals in the size range of 5–20 μm were successfully synthesized via a sonochemical route in a substantially reduced synthesis time (40 min) in the presence of low-cost NMP (1-methyl-2-pyrrolidone) as a solvent. Microwave heating in NMP also produced MOF-177 under similar conditions (35 min, 5–50 μm) but exhibited inferior crystallinity. In comparison, a conventional solvothermal route in DEF (diethylformamide) took 48 h to produce MOF-177 crystals 0.5–1.5 mm in size. The BET surface areas of the MOF-177 samples decreased in the order of sonochemical (4898 m² g⁻¹) > conventional (4833 m² g⁻¹) > microwave route (4197 m² g⁻¹). In line with this trend, MOF-177 prepared via the sonochemical route resulted in the highest CO₂ adsorption capacity, 1315 mg g⁻¹ at 30 bar and 298 K. The product yield of MOF-177 synthesized via the sonochemical route was 95.6%, and was significantly higher than the product yields of other methods.