Ligand Body Reorganization of Metal Nanoclusters for Enhanced Electrocatalytic CO2 Reduction Reactivity

Abstract The reactivity of metal nanoparticles depends on the adsorption of molecules or ions on their active sites, which are often limited by surface ligands. Unlike conventional surface activation methods that involve ligand removal, this study presents an alternative surface regulation technique to adjust the reactivity of metal nanoparticles. This method reorganizes ligand bodies while maintaining the size and metal packing structure of the nanoparticles. Using atomically precise [Au 25 ( p ‐MBA) 18 ] − nanoclusters, where p ‐MBA represents para ‐mercaptobenzoic acid, this study demonstrates that synergistic hydrogen bonds and ion‐pairing interactions between foreign guanidinium cations and anionic p ‐MBA ligands effectively reorganize the ligand bodies on the cluster surface, thereby enhancing the accessibility of active gold sites to small molecules such as CO or CO 2 . This approach enables further size‐growth reaction of [Au 25 ( p ‐MBA) 18 ] − , facilitating cluster growth into larger sizes such as Au 38 ( p ‐MBA) 24 and Au 84 ( p ‐MBA) 40 . The electrocatalytic performance of Au 38 ( p ‐MBA) 24 and Au 84 ( p ‐MBA) 40 in CO 2 reduction can be significantly improved by guanidinium‐assisted ligand body reorganization, without affecting their durability.