Facile Exfoliation of Two-Dimensional Crystalline Monolayer Nanosheets from an Amorphous Metal-Organic Framework

The large-scale preparation of monolayer two-dimensional (2D) material remains a great challenge, which hinders its real-world applications. Herein, we report a novel layered metal-organic framework (MOF), IPM-1, which was synthesized from a cage-like organic linker, with extremely weak interlaminar interaction. When subjected to external disturbance, IPM-1 degenerated into an intermediate state between the crystalline and amorphous phase, in which the layers retain the in-plane two-dimensional periodic structure but are misaligned in the third dimension, leading to the loss of apparent porosity and crystallinity. This amorphous IPM-1 is readily exfoliated at gram scale into crystalline 2D nanosheets with a thickness of 1.15 nm, excellent thickness homogeneity, lateral size up to 10 mu m, and restored microporosity. IPM-1 nanosheets exhibit high chemical stability and catalytic activity in the oxidation of alcohol, combining the advantages of both homogeneous and heterogeneous catalyst. This work underscores that MOFs without apparent crystallinity can be ideal precursors for the successful preparation of 2D crystalline monolayer nanosheets. [GRAPHICS]

Automated summary

In this study, a novel metal-organic framework (MOF) IPM-1 was synthesized and found to be capable of being exfoliated into two-dimensional nanosheets with excellent thickness homogeneity and restored microporosity. These nanosheets exhibited high chemical stability and catalytic activity in the oxidation of alcohol, combining the advantages of both homogeneous and heterogeneous catalysts.