Pendant Group Design Toward Molecular Packing of Metal‐Organic Frameworks Nanosheets in Micrometer‐Scale for Photo‐Thermal Catalysis

Abstract Attempts that can fabricate metal‐organic frameworks (MOFs) into large‐scale nanosheets with high crystallinity and multi‐functions are much desired for their extended applications. Here, through the pendant group design of ligands, we have successfully prepared a kind of two‐dimensional MOFs (i.e., 2D‐Cu(NDI‐NHEt)) and a contrast three‐dimensional Cu 3 ‐based MOFs (i.e., 3D‐Cu(NDI‐H)) via different side chain induction effects. Interestingly, 2D‐Cu(NDI‐NHEt) can be easily exfoliated into micrometer‐scale nanosheets (i.e., 2D‐Cu(NDI‐NHEt) NSs), while 3D‐Cu(NDI‐H) is hard to exfoliate under similar conditions. Notably, the obtained 2D‐Cu(NDI‐NHEt) NSs possesses high crystallinity, porous structure, ultrathin thickness (∼1.3 nm) and abundant functional units that can be successfully applied in photo‐thermal catalysis, demonstrating much better performance than 2D‐Cu(NDI‐NHEt) and 3D‐Cu(NDI‐H). The structure‐to‐property relationships and possible mechanisms have been revealed by various characterizations coupled with theoretical calculations. These findings offer key understanding of molecular assembly in fabrication of MOFs into large‐scale nanosheets for efficient photocatalytic applications.