Unraveling a Ligand-initiated Oxidative Etching Pathway in Gold Nanoclusters

Chemical etching is a crucial strategy for engineering metal nanoclusters, and understanding the etching pathway can facilitate their precise fabrication. While previous studies have highlighted the roles of oxygen and thiols, the reaction pathways involving these two reactants remain underexplored. This study revisits the oxidative etching of [Au25(p-mercaptobenzoic acid)18]- by manipulating ligand concentrations, revealing two distinct pathways. The etching process may be initiated by the reaction with either thiols or oxygen, with thiol concentration serving as the key factor in pathway selection. These findings provide mechanistic insights into the etching process and illuminate the potential for nanocluster diversification.