Room-Temperature Synthesis of Two-Dimensional Metal–Organic Frameworks with Controllable Size and Functionality for Enhanced CO₂ Sorption

Abstract

Two-dimensional (2D) metal–organic frameworks (MOFs), as a newly emerged member of 2D materials, have gained extensive attention due to their great potential in gas separation, sensing, and catalysis. However, it is still challenging to synthesize 2D MOFs with controllable size and functionalities using direct and scalable approaches at mild conditions (e.g., room temperature). Herein, we demonstrated one-step, room-temperature synthesis of a series of 2D MOFs based on Cu­(II) paddle-wheel units, where the intrinsically anisotropic building blocks led to the anisotropic growth of 2D MOF nanoparticles, and the pillared structure led to high surface areas. The size of 2D MOFs can be adjusted by using a DMF/H2O mixed solvent. The thinnest particles were around 3 nm, and the highest aspect ratio was up to 200. The functionalization of 2D MOFs was also achieved by selecting ligands with desired functional groups. The gas sorption results revealed that amino and nitro-functionalized 2D MOFs showed higher CO2 sorption selectivity over CH4 and N2, suggesting these materials can be further applied in natural gas sweetening (CO2/CH4 separation) and carbon capture from flue gas (CO2/N2 separation).

2D Free‐Standing Nitrogen‐Doped Ni‐Ni3S2@Carbon Nanoplates Derived from Metal–Organic Frameworks for Enhanced Oxygen Evolution Reaction

“…Noting that pyridine is not only a kind of monodentate ligand using as inhibitor to suppress the growth of the crystal, but also a good organic solvent for both metal salt and organic ligand . It can be inferred that the increase of pyridine will enhance the solvability of the reaction solution, leading to a higher tolerance for larger pieces before precipitation without obvious effect on the thickness . The X‐ray diffraction (XRD) patterns of nanoplates with different size are depicted in Figure S1 in the Supporting Information.…”

Crystallization of high aspect ratio HKUST-1 thin films in nanoconfined channels for selective small molecule uptake

“…6 †), an improvement on previously reported results. 33,38 Conversely, the larger depth channels ($300 nm) produce aspect ratios on the order of 200. This nding suggests that depth connement was signicant to producing the highest aspect ratio MOF crystals.…”

“…We observed crystal formation with aspect ratios up to 2500, exceeding that of any other previously reported MOFs to the best of the authors' knowledge. 32,33 Finally, the capacity for selective molecular uptake and exclusion in high aspect ratio HKUST-1 crystals is demonstrated using anthracene, methylene blue, rhodamine B and riboavin.…”

2D Metal–Organic Frameworks as Multifunctional Materials in Heterogeneous Catalysis and Electro/Photocatalysis

“…Connected with the control in the synthesis of MOFs, one of the possibilities that is currently attracting much interest are procedures for arresting the growth of the crystals in a 3D structure, allowing the synthesis of lamellar materials with 2D morphology and high lateral area‐to‐thickness aspect ratio . It should be noted that the concept of 2D MOFs not only includes one‐atom thick, single layered lamellar MOFs, but also those crystals with a high lateral to thickness aspect ratio crystallites that may still contain pores between the upper and bottom surfaces.…”