HIGHLIGHTS• The advantages of macroporous metal-organic frameworks (MOFs) in comparison with micro-and mesoporous MOFs are discussed.• A range of synthetic methods for the fabrication and characterisation of hierarchical MOFs with macroporosity are reviewed.• The applications, advancements, and challenges of each method are compared and assessed in detail.ABSTRACT Introduction of multiple pore size regimes into metalorganic frameworks (MOFs) to form hierarchical porous structures can lead to improved performance of the material in various applications.In many cases, where interactions with bulky molecules are involved, enlarging the pore size of typically microporous MOF adsorbents or MOF catalysts is crucial for enhancing both mass transfer and molecular accessibility. In this review, we examine the range of synthetic strategies which have been reported thus far to prepare hierarchical MOFs or MOF composites with added macroporosity. These fabrication techniques can be either pre-or post-synthetic and include using hard or soft structural template agents, defect formation, routes involving supercritical CO 2 , and 3D printing. We also discuss potential applications and some of the challenges involved with current techniques, which must be addressed if any of these approaches are to be taken forward for industrial applications.

No abstract

International audienceMetal–organic frameworks (MOFs) have attracted considerable attention in the past several years in the area of hydrogen storage. Various modification strategies have been performed to enhance the hydrogen storage capacity in MOFs both at room temperature and cryogenic temperatures. In this study a hybrid composite MOF was synthesised by adding activated carbon (AC) NORIT-RB3 in situ during the synthesis of MIL-101 and lithium doping at various lithium ion concentrations were done in the synthesised composite material. Hydrogen adsorption–desorption studies were performed at 77 K and 298 K up to 100 bar in all the samples. For all materials studied, isosteric heat of adsorption has been calculated from the measured isotherms of adsorption. The results of adsorption showed that the hydrogen uptake capacity of MIL-101 could be considerably enhanced by the combined modification of MIL-101 using activated carbon and lithium doping. Here we present a simple way which can enhance the hydrogen uptake capacity of MIL-101 material at 77 K and 298 K. Activated carbon NORIT-RB3 is not costly compared to other carbon materials such as carbon nanotubes and thus this method is very cheap also. However the percentage of lithium doping should be controlled since large concentrations of lithium destroy the framework structure of MIL-101

No abstract

No abstract

No abstract

Lithium doped MIL-101 and MIL-53(Al) was prepared by solution impregnation method from MetalOrganic Frameworks (MOFs), MIL-101 and MIL-53(Al) using lithium naphthalenide (C 10 H 7 Li) solution. The doping was repeated to get two different concentrations of lithium doped MIL-101 and MIL-53(Al) respectively. The powder X-ray diffraction studies of the doped materials showed that the framework crystallinity of the synthesized materials was not affected by lithium doping. However N 2 adsorption-desorption studies at 77 K showed a decrease in the BET surface area and pore volume values as the concentration of Li ions increases inside the framework. Hydrogen adsorption-desorption measurements were performed in lithium doped MIL-101 and MIL-53(Al) samples both at 77 and 298 K under high pressure (up to 100 bar). The results obtained were original and also useful considering that the experimental studies of high pressure hydrogen adsorption in lithium doped MOFs are scarce. This study also showed that the hydrogen adsorption capacities of MIL-101 and MIL-53(Al) can be significantly enhanced by lithium ion doping but controlled doping of lithium is necessary for good adsorption capacities as higher concentration of lithium destroys the framework structure of the materials.