Abstract

Numerous studies constantly showed that gold clusters react with O2 only forming molecularly adsorbed products, and the reactions are closely correlated with clusters' global electronic properties, such as the spins, the electron affinities, and the energy gaps. Combining cluster reaction experiments and theoretical calculations, this work shows that gold clusters doped by a silicon atom, AunSi– (n = 3–8 and 16), react with O2 in peculiar ways, in which the influence of the doping sites takes precedence over clusters' global electronic properties. At the doping sites where the silicon atom retains its covalent character by having dangling gold atom(s), the O2 molecule is inclined to be adsorbed on a dangling gold atom. At the exohedral doping sites where silicon atoms are exposed, the O2 molecule undergoes significant activation, resulting in its dissociation, and the energy released during this process actively facilitates the detachment of a resulting SiO2 unit. The site-dependent reaction pathways of O2 on silicon-doped gold clusters suggest the potential for intentionally designing active sites on gold catalysts through non-metal doping, and also shed light on the stability of microstructures on surfaces of gold–silicon alloy systems. They can additionally be used as structural probes due to the large sizes within this doped gold cluster family.