Ligand codes: 1,3,5-BTC – benzene-1,3,5-tricarboxylic acid; 1,2,4-BTC – benzene-1,2,4-tricarboxylic acid; BDC – benzene-1,4-dicarboxylic acid; CA – citric acid; and MIM – 2-methyl imidazole. Binder codes: MSE – methoxy-siloxane ether; PVA – polyvinyl alcohol; PVC – polyvinyl chloride; KH570 – 3(trimethoxysilyl)propyl methacrylate; and MC – methyl cellulose. Plasticizer codes: MHPC – methyl hydroxyl propyl cellulose and DMF – N, N-dimethylformamide. “—” not specified. a Measured by Hg intrusion. Fig. 9 Schematic representation of the 3D printing process via the Direct Ink Writing (DIW) method. The “Meilleur Ouvrier de France”competition was created in France in 1924 with the objective to revive the dwindling number of traditional craftsmen in France and recognize those who represent “high qualification in the exercise of a professional activity in the craft, commercial, service, industrial or agricultural.”

The extrudates were further applied for CO 2 and water-vapor adsorptions. The latter revealed identical isotherm shapes for both the powder and extrudates. This suggests that the intrinsic hydrophilicity/hydrophobicity balance of HKUST-1 was not altered upon shaping. Besides, CO 2 adsorption experiments at 25 °C revealed gravimetric uptakes of 218 and 129 mg g −1 for the MOF in powder and extruded forms, respectively. The decrease of CO 2 uptake demonstrated by the latter is in agreement with the loss in specific surface area upon extrusion. C. Wang, Y. V. Kaneti, Y. Bando, J. Lin, C. Liu, J. Li and Y. Yamauchi, Metal–organic framework-derived one-dimensional porous or hollow carbon-based nanofibers for energy storage and conversion, Mater. Horiz., 2018, 5, 394–407, 10.1039/C8MH00133B.Therefore, each of the shaping techniques provides unique features to the final objects in terms of size and appearance for a defined application. This review will focus on conventional shaping techniques such as granulation, pelletization, extrusion, and spray-drying and challenges associated upon formulation of MOF powders. This will also include the 3D printing method as it can be referred to as a type of extrusion with controlled deposition of the forming paste in three dimensions in space. Therefore, 3D printing allows shaping powders with desired shapes and dimensions for a wide variety of applications. They will be as well discussed in the corresponding section along with the challenges related to the formulation of MOF powders. Besides, a separate section will be dedicated to the so-called non-conventional techniques which include freeze granulation, ice templating and biopolymer precipitation. Membranes and coatings, and sol–gel-based monoliths have been excluded from this review on purpose as they have been recently reviewed. 19 Finally, Lawson et al. 111 studied the post-printing crystallization of HKUST-1 starting from a gel containing all precursors. In this case, a mixture of bentonite (21 wt%), methylcellulose (2 wt%) and PVA (6 wt%) was used to obtain satisfactory rheological properties. The as-printed grids presented a fair replication of the initial model, and they were further placed in a convection oven at 120 °C for 20 hours to induce crystallization of the MOF. The resulting material presented a S BET of 500 m 2 g −1, slightly higher than that of a comparative solid directly 3D-printed starting from the HKUST-1 powder (470 m 2 g −1). While the solids were extensively washed with acetone, residual DMF was observed by FTIR spectroscopy as characterized by a band at 2100 cm −1. Finally, the CO 2 capacities of both solids at 25 °C were compared. While the solid prepared from the HKUST-1 powder presented a CO 2 capacity 50% higher (2.1 mmol g −1 against 1.4 mmol g −1), which is not in line with their respective S BET, the solid obtained by growing HKUST-1 crystals on the as-printed solid displayed enhanced mass transfer kinetics (diffusivity × 10 8 (cm 2 s −1): 8.75 against 5.25). This was attributed to the presence of a larger extent of mesopores ( V meso (cm 3 g −1 STP) = 0.16 against 0.09). V. Finsy, L. Ma, L. Alaerts, D. E. De Vos, G. V. Baron and J. F. M. Denayer, Separation of CO 2 / CH 4 mixtures with the MIL-53 (Al) metal–organic framework, Microporous Mesoporous Mater., 2009, 120, 221–227, DOI: 10.1016/j.micromeso.2008.11.007.

R. R. Salunkhe, Y. V. Kaneti and Y. Yamauchi, Metal−Organic Framework-Derived Nanoporous Metal Oxides toward Supercapacitor Applications: Progress and Prospects, ACS Nano, 2017, 11, 5293–5308, DOI: 10.1021/acsnano.7b02796.Typically, MOFs are produced in polycrystalline powder form, with the size of individual crystals ranging from several tens of nanometers to a few microns. Continuous studies on synthesis optimization and product characterization have stimulated the production of MOFs on a larger scale. Thus, a number of them are now commercially available and provided by BASF (HKUST-1/Basolite C300, ZIF-8/Basolite Z1200, Fe-BTC/Basolite F300), Strem Chemicals (CAU-10, MIL-53(Al), MIL-101(Al), PCN-250(Fe), UiO-66), and others. A further study done by Boix et al. 143 in Maspoch's group led to the incorporation of inorganic nanoparticles into UiO-66 microbeads. The process followed the same sequence of steps, including the formation of primary nuclei in the flow reactor at 115 °C with a feed rate of 2.4 mL min −1, an inlet temperature of 180 °C, and a flow rate of 336 mL min −1. The thus-formed UiO-66 microbeads exhibited an average size of 1.5 ± 1.0 μm with a crystalline framework corresponding to the UiO-66. Additionally, the beads had a high surface area ( S BET = 945 m 2 g −1), which was slightly below than the one obtained by Garzon-Tovar et al. ( S BET = 1106 m 2 g −1) 138 following the same method. The difference might be attributed to the Zr-source used in each case: zirconium propoxide and zirconium tetrachloride, respectively. Interestingly, the UiO-66 itself was shown to be active towards the adsorption of toxic heavy metals such as Cr( VI) and As( V) with removal efficiencies of 99 and 45%, respectively. However, once functionalized with thiol (–SH) groups and doped with CeO 2 nanoparticles, it became active and efficient towards heavier metal species including Cd( II), Cu( II), Pb( II) and Hg( II) with removal efficiencies of 87, 99, 99 and 98%, respectively. Importantly, CeO 2-doped UiO-66-(SH) 2 microbeads retained their removal efficiency after 10 adsorption/desorption cycles in a continuous flow column, making them appropriate for further developments as water-purifying adsorbents. Linker codes: BDC – benzene-1,4-dicarboxylic acid; BTB – 1,3,5-benzenetribenzoate; MIM – 2-methyl imidazole; MIC – 4-methyl-5-imidazolecarboxaldehyde; BTC – benzene-1,3,5-tricarboxylic acid; DHBDC – 2,5-dihydroxy-1,4-benzenedicarboxylic acid; BPDC – biphenyl-4,4′-dicarboxylic acid; and FA – formic acid. Binder codes: PVA – polyvinyl alcohol; SB – pseudoboehmite; and PVB – polyvinyl butyral. “—” not specified. a Used as an additive to improve thermal conductivity. The craftsmanship exhibition has been held every three to four years and showcases different professions including florists, carpenters, butchers, jewelry makers, and of course pastry chefs, to name just a few. Along with the title, winners receive a medal and state diploma.

F. Lorignon, A. Gossard and M. Carboni, Hierarchically porous monolithic MOFs: An ongoing challenge for industrial-scale effluent treatment, Chem. Eng. J., 2020, 393, 124765, DOI: 10.1016/j.cej.2020.124765.The MOF competition and its preparation are definitely in my top lifetime memories. The hours of preparation, the stress of the competition, the recognition for all the work and commitment, have alla All has changed me forever. I have pushed myself beyond what I imagined possible and it certainly contributed in making me a better professional.” continues Meilleur Ouvrier de France Chef Thomas Marie The culinary connection In 2014 Ahmed et al. 156 proposed a different method for MOF shaping based on controlled freezing. According to it, a MOF powder in suspension can be shaped into monoliths upon controlled freezing of the solvent with its subsequent elimination via freeze-drying. The authors applied this methodology to obtain Cu-based HKUST-1 monoliths. For this, the MOF precursors were dissolved in DMSO and left for 24 h at 80 °C. After that, the solution was frozen in liquid nitrogen for 1 min and placed into a freeze-dryer to sublime the solvent. This procedure yielded highly crystalline HKUST-1 monoliths as confirmed by XRD. Moreover, the specific surface area was 870 m 2 g −1 with characteristics of both micropores and mesopores, as visible from the N 2 physisorption isotherms. Additionally, as shown by Hg intrusion, the monoliths exhibited macropores with diameters around 0.4 and 10 μm. Importantly, these macropores generated upon ice-templating were oriented in one particular direction due to the orientational growth of ice crystals during freezing. Lastly, the authors showed that the size of these macropores could be varied by altering the freezing temperature. Thus, upon freezing at 5 °C the macropores were two times bigger (∼50 μm) than the macropores generated upon freezing at −80 and −20 °C (32 and 25 μm, respectively). A. Dhakshinamoorthy, Z. Li and H. Garcia, Catalysis and photocatalysis by metal organic frameworks, Chem. Soc. Rev., 2018, 47, 8134–8172, 10.1039/C8CS00256H. J. J. Purewal, D. Liu, J. Yang, A. Sudik, D. J. Siegel, S. Maurer and U. Mu, Increased volumetric hydrogen uptake of MOF-5 by powder densification, Int. J. Hydrogen Energy, 2012, 37, 2723–2727, DOI: 10.1016/j.ijhydene.2011.03.002.