DFT calculations on subnanometric metal catalysts: a short review on new supported materials

Metal clusters have been used in catalysis for a long time, even in industrial production protocols, and a large number of theoretical and experimental studies aimed at characterizing their structure and reactivity, either when supported or not, are already present in the literature. Nevertheless, in the last years the advances made in the control of the synthesis and stabilization of subnanometric clusters promoted a renewed interest in the field. The shape and size of sub-nanometer clusters are crucial in determining their catalytic activity and selectivity. Moreover, if supported, subnanometric clusters could be highly influenced by the interactions with the support that could affect geometric and electronic properties of the catalyst. These effects also present in the case of metal nanoparticles assume an even more prominent role in the "subnano world." DFT-based simulations are nowadays essential in elucidating and unraveling reaction mechanisms. The outstanding position of this corner of science will be highlighted through a selected number of examples present in the literature, concerning the growth and reactivity of subnanometric supported metal catalysts.