Electrostatic Interactions Induced Ligand Re‐orientation for Catalytic Performance Improvement of Metal Nanoclusters

Comprehensive Summary Catalytic activity and durability represent a long‐lasting dilemma in catalytic applications of metal nanoparticles. Herein, we report a dehydration‐rehydration strategy for immobilizing metal nanoclusters (NCs, <3 nm nanoparticles) on MgAl layered double hydroxides (MgAl‐LDHs) for simultaneously promoting their catalytic activity and durability. This approach relies on the reversible dehydration‐rehydration process of MgAl‐LDHs, in which anionic Au 25 ( p ‐MBA) 18 NCs ( p ‐MBA = para ‐mercaptobenzoic acid) can be effectively tethered on positively charged MgAl hydroxide layers to yield Au 25 /LDH composites. The strong electrostatic interactions of 2D MgAl hydroxide layers with carboxylate groups of p ‐MBA ligands are effective in re‐orientating the p ‐MBA ligands on cluster surface, exposing more active Au sites for catalytic reactions. Such enhanced active Au site accessibility is conducive to improving catalytic activity of Au 25 /LDH composites toward selective reduction of 4‐nitrophenol to 4‐aminophenol. Au 25 /LDH composites achieve complete conversion of 4‐nitrophenol within 180 s with a rate constant of 0.0183 s –1 , while their catalytic activity remains uncompromised within ten catalytic cycles. This study not only provides a simple yet effective strategy for stabilizing and activating metal NCs for catalytic applications, but also affords an alternative mechanism for engineering the catalytic activity of metal NCs via ligand re‐orientation.