Creating hydrophobic nanopockets in metal–organic frameworks to promote hydrodeoxygenation of lignin derivatives under ambient conditions

The construction of homogeneous-like reaction environments in the vicinity of heterogeneous active sites is an effective artificial method for replicating the catalytic activity of natural enzymes. In this work, we fabricated hydrophobic nanopockets in metal-organic frameworks (MOFs) and confined Pd nanoclusters in them to mimic the joint action of metal centers and proximal cofactors in enzyme catalysis. The hydrophobic microenvironment of the MOF pore was introduced by the functional group (-CH₃) modification on the organic linkers, which provide noncovalent interactions for substrate enrichment and ultimately create homogeneous-like conditions for the catalyst to exert its intrinsic activity. The obtained Pd@UIO-66-CH₃ composite with enhanced hydrophobic interaction exhibited high catalytic performance for the hydrodeoxygenation of lignin-derived aromatic alcohols/aldehydes under ambient conditions. This work elucidates the importance of the microenvironment around the active site in catalysis and provides new ideas for designing artificial enzyme catalytic systems with substrate-specific recognition.