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Mg-MOF-74 crystals were successfully prepared in 1 h by a sonochemical method (Mg-MOF-74(S)) after triethylamine (TEA) was added as a deprotonating agent. Mg-MOF-74(S) (1640 m 2 g À1 BET surface area) displayed similar textural properties to those of a high-quality MOF sample synthesized in 24 h by the solvothermal method (Mg-MOF-74(C), 1525 m 2 g À1 ). However, mesopores were formed, probably due to the competitive binding of TEA to Mg 2+ ions, and the average particle size of the former (ca. 0.6 mm) was significantly smaller than that of the latter (ca. 14 mm). The H 2 O adsorption capacity was 593 mL g À1 at 298 K for Mg-MOF-74(S), displaying higher hydrophilicity than Zeolite 13X. The adsorption isotherms of Mg-MOF-74(S) for CO 2 showed high adsorption capacity (350 mg g À1 at 298 K) and high isosteric heats of adsorption for CO 2 (42 to 22 kJ mol À1 ). The breakthrough experiment confirmed excellent selectivity to CO 2 over N 2 at ambient conditions (saturation capacity of ca. 179 mg g À1 ). Ten consecutive adsorption-desorption cycles at 298 K established no deterioration of the adsorption capacity, which showed reversible adsorbent regeneration at 323 K under helium flow for a total duration of 1400 min. Mg-MOF-74(S) also demonstrated excellent catalytic performance in cycloaddition of CO 2 to styrene oxide under relatively mild reaction conditions (2.0 MPa, 373 K) with close to 100% selectivity to carbonate, which was confirmed by GC-MS, 1 H-NMR, and FT-IR. Mg-MOF-74(S) could be reused 3 times without losing catalytic activity and with no structural deterioration.

A polyethylenimine-impregnated hierarchical silica monolith exhibited significantly higher CO(2) capturing capacity than other silica-supported amine sorbents, and produced a reversible and durable sorption performance.

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Herein, we report a novel nanoliter droplet-based microfluidic strategy for continuous and ultrafast synthesis of metal-organic framework (MOF) crystals and MOF heterostructures. Representative MOF structures, such as HKUST-1, MOF-5, IRMOF-3, and UiO-66, were synthesized within a few minutes via solvothermal reactions with substantially faster kinetics in comparison to the conventional batch processes. The approach was successfully extended to the preparation of a demanding Ru3BTC2 structure that requires high-pressure hydrothermal synthesis conditions. Finally, three different types of core-shell MOF composites, i.e., Co3BTC2@Ni3BTC2, MOF-5@diCH3-MOF-5, and Fe3O4@ZIF-8, were synthesized by exploiting a unique two-step integrated microfluidic synthesis scheme in a continuous-flow mode. The synthesized MOF crystals were characterized by X-ray diffraction, scanning electron microscopy, and BET surface area measurements. In comparison with bare MOF-5, MOF-5@diCH3-MOF-5 showed enhanced structural stability in the presence of moisture, and the catalytic performance of Fe3O4@ZIF-8 was examined using Knoevenagel condensation as a probe reaction. The microfluidic strategy allowed continuous fabrication of high-quality MOF crystals and composites exhibiting distinct morphological characteristics in a time-efficient manner and represents a viable alternative to the time-consuming and multistep MOF synthesis processes.

High quality MOF-5 crystals of 5-25 mum in size were prepared for the first time using a sonochemical method in substantially reduced synthesis time (ca. 30 min) compared with conventional solvothermal synthesis (24 h).

Free-radical polymerization inside mesoporous silica has been investigated in order to open a route to functional polymer-silica composite materials with well-defined mesoporosity. Various vinyl monomers, such as styrene, chloromethyl styrene, 2-hydroxyethyl methacrylate, and methacrylic acid, were polymerized after impregnation into mesoporous silicas with various structures, which were synthesized using polyalkylene oxide-type block copolymers. The location of the polymers was systematically controlled with detailed structures of the silica framework and the polymerization conditions. Particularly noteworthy is the polymer-silica composite structure obtained by in situ polymerization after the selective adsorption of monomers as a uniform film on silica walls. The analysis of XRD data and the N(2) adsorption isotherms indicates the formation of uniform polymer nanocoating. The resultant polymer-silica composite materials can easily be post-functionalized to incorporate diverse functional groups in high density, due to the open porous structure allowing facile access for the chemical reagent. The fundamental characteristics of the composite materials are substantiated by testing the biomolecule's adsorption capacity and catalytic reactivity. Depending on the structure and composition of polymers, the resultant polymer-silica composite materials exhibit notably distinct adsorption properties toward biomolecules, such as proteins. Furthermore, it is demonstrated that the nanocoatings of polymers deposited on the mesopore walls have remarkably enhanced catalytic activity and selectivity, as compared to that of bulk polymer resins. We believe that, due to facile functionalization and attractive textural properties, the mesoporous polymer-silica composite materials are very useful for applications, such as adsorption, separation, host-guest complexes, and catalysis.