Tuning the Reactivity of Small Metal Clusters by Heteroatom Doping

ConspectusThe reactivity of small metallic clusters, nanoparticles composed of a countable number of atoms (typically up to ∼100 atoms), has attracted much attention due to the fascinating properties these objects possess toward a variety of molecules. Cluster reactivity often is significantly different from the homologous bulk, with gold as prototypical example. Bulk gold is the noblest of all metals, whereas small gold clusters react with carbon monoxide, molecular oxygen, and hydrocarbons, among others. Furthermore, cluster reactivity is strongly size and composition dependent, allowing a wide range of tuning possibilities.The study of cluster reactivity usually follows two routes of investigation. In the first, research aims for fundamental understanding of mechanisms, mainly driven by curiosity. One consequence of the inherent small size of a cluster is that atoms can arrange themselves very differently from the crystallographic structure of the homologous bulk. In addition, quantum confinement effec...