The wet synthesis and quantification of ligand-free sub-nanometric Au clusters in solid matrices.

The synthesis of ligand-free sub-nanometric metal clusters on a large scale suffers typically from very low yields (<5% yield) and needs very high dilutions. Here we show that Au clusters can be prepared with ethylene-vinyl alcohol copolymers (EVOH), charcoal, and different metal oxides (CeO2, Al2O3, TiO2 and ZnO) in >15% yields, as unambiguously determined using a very simple and extremely sensitive analytical reaction test.