Hierarchically Micro‐ and Mesoporous Metal–Organic Frameworks with Tunable Porosity

Abstract

Porous metal-organic frameworks (MOFs) are crystalline materials with pores and channels self-assembled by the bonding of metal ions with multifunctional organic ligands.

Template synthesis of hierarchical porous metal–organic frameworks with tunable porosity

“…All of the Cu-BTC_An samples exhibit lower Brunauer-EmmettTeller (BET) surface areas (S BET ) than C-Cu-BTC, which can be attributed to the increased fraction of meso-and macropores decreasing S BET . Similar conclusions were drawn from the works of Qiu et al, 20 Yue et al, 22 and Huang et al 14 However, all Cu-BTC_An products have much higher total pore volumes (V t ) and mesopore volumes (V meso ) than C-Cu-BTC, conrming the generation of mesopores in the Cu-BTC_An samples. In addition, as the amount of template is increased from 0.45 to 4.5 mmol during synthesis, V t of the MOF products is increased from 0.66 (for Cu-BTC_A1) to 0.81 cm 3 g À1 (for Cu-BTC_A3), and V meso is also increased from 0.19 to 0.31 cm 3 g À1 .…”

“…Finally, the template was removed to yield mesopores and/or macropores with walls formed by the crystalline microporous MOF. 26 Qiu et al, 20 and Sun et al, 63 also reported a similar mechanism for synthesizing hierarchically structured MOFs by using a template strategy.…”

“…To solve the diffusion and accessibility problems that guest species face in conventional MOFs with micropores, hierarchical porous MOF materials (HP-MOFs; MOFs with micro-and mesopores, or MOFs with micro-, meso-, and macropores) with tunable porosity, such as Cu-BTC, 20 ZIF-8, 21 and Zn-MOF-74, 22 have been successfully synthesized since 2008. The extended pore structures (mesopores or macropores, or both mesopores and macropores) in HP-MOF materials can improve the diffusion rate and facilitate mass transfer of reactants or products.…”

“…20,29 The triblock copolymers P123 and F127, which are widely applied to synthesize mesoporous zeolites, have also been used as templates to prepare stable HPMOFs (e.g., Cu-BTC). [30][31][32] Other new kinds of templates have also been reported for the synthesis of HP-MOFs, such as amphiphilic dodecanoic acid (DDA),…”

Metal–organic framework growth at functional interfaces: thin films and composites for diverse applications

“…Cationic quaternary amine-based surfactant assemblies are commonly used for the preparation of mesoporous silicas, and Qiu et al have followed a similar strategy to access MOFs with 40 combined micro-and mesoporosity. 175 Cetyl trimethyl ammonium bromide (CTAB) was added to standard HKUST-1 solvothermal synthesis mixtures at various molecular ratios to template mesoporosity within the microporous framework as the metal ions and ligands assemble around the surfactant micelles. 45 ( Fig.…”