From 2D to 3D: Postsynthetic Pillar Insertion in Electrically Conductive MOF

Abstract

The emergence of 2D electrically conductive metal–organic frameworks (MOFs) has significantly expanded the scope of metal–organic framework applications from electrochemical energy storage to electronic devices. However, their potentials are not fully exploited due to limited accessibility to internal pores in stacked 2D structures. Herein we transform a 2D conjugated MOF into a 3D framework via postsynthetic pillar-ligand insertion. Cu-THQ was chosen due to its ability to adopt additional ligands at the axial positions at the copper nodes. Cu-THQ demonstrates that structural augmentation increases ion accessibility into internal pores, resulting in an increased gravimetric capacitance up to double that of the pristine counterpart. Beyond this, we believe that our findings can further be used to functionalize the existing 2D conductive MOFs to offer more opportunities in sensing, electronic, and energy-related applications by utilizing additional functions and increased accessibility from the pillars.

A Ni(II) Metal–Organic Framework with Mixed Carboxylate and Bipyridine Ligands for Ultrafast and Selective Sensing of Explosives and Photoelectrochemical Hydrogen Evolution

“…As the water reduction potential lies at 0 V vs NHE, so it can be concluded that photogenerated electrons of Ni-SIP-BPY with a more negative potential (−0.37 V vs NHE) may have ability to reduce the water and are capable of H 2 generation. Furthermore, we have also calculated the electrochemically active surface area (ECSA) through electrochemical double-layer capacitance measurement ( C dl ) . The electrochemical double-layer capacitance was evaluated by measuring cyclic voltammetry (CV) data in the non-Faradic region at different scan rates from 20 to 200 mV/s (Figure S19b) in 0.1 M Na 2 SO 4 medium, and the observed value was 0.026 mF cm –2 .…”

“…Furthermore, we have also calculated the electrochemically active surface area (ECSA) through electrochemical doublelayer capacitance measurement (C dl ). 66 The electrochemical double-layer capacitance was evaluated by measuring cyclic voltammetry (CV) data in the non-Faradic region at different scan rates from 20 to 200 mV/s (Figure S19b) in 0.1 M Na 2 SO 4 medium, and the observed value was 0.026 mF cm −2 .…”

Reversibly Phase-Transformative Zeolitic Imidazolate Framework-108 and the Membrane Separation Utility

“…22,23 For example, researchers found that a nonporous interpenetrated framework, Zn(cyanide) 2 , underwent lattice distortion at the high pressure of 1.50−1.58 GPa, and transformed into noninterpenetrated porous phases with three different kinds of topologies in pressure-transmitting fluids. 21 Another example highlighted a transformation from two-dimensional (2D) MOFs to three-dimensional (3D) frameworks by pillar insertion, 24 corresponding to an increment of surface area with structural augmentation.…”

“…Lattice transition commonly includes (1) breathing triggered by guest molecules, that is, lattice switching between the large pore and narrow pore; − (2) structural distortion as a result of linker rotation and reorientation; , (3) lattice contracting/expanding via external stimuli such as temperature; , and (4) complete topological transformation with respect to the reorganization of secondary building units driven by the cleavage and reconstruction of metal-linker chemical bonds. , For example, researchers found that a nonporous interpenetrated framework, Zn­(cyanide) 2 , underwent lattice distortion at the high pressure of 1.50–1.58 GPa, and transformed into non-interpenetrated porous phases with three different kinds of topologies in pressure-transmitting fluids . Another example highlighted a transformation from two-dimensional (2D) MOFs to three-dimensional (3D) frameworks by pillar insertion, corresponding to an increment of surface area with structural augmentation.…”

Decoupling layer metal–organic frameworks via ligand regulation to achieve ultra-thin carbon nanosheets for oxygen reduction electrocatalysis

“…benzene and triphenylene) are optimal because the coordination tends to form strong inplane conjugation and π-π stacking. 17,18 This in-plane conjugated effect possesses the ability to interact with out-of-plane van der Waals, which promotes the intrinsic charge transport of 2D MOF layers. 19,20 Such a strong interaction caused by electron coupling at a large plane greatly restricts the exfoliation of 2D MOF-derived carbon sheet layer, resulting in inadequate exposure of active sites.…”