Unraveling the Solvent Regulation in the Heteroatom-Doped Endohedral Gold Clusters: A Theoretical Study on the Electronic Properties and O Activation.

Liquid-phase synthesis of atomically precise nanoclusters has experienced rapid development recently, where polar solvents are indispensable in such a process. However, the regulation effect of solvents on the structural and electronic properties of different metal clusters and cluster assembly materials is still not well understood. Herein, a comprehensive density functional theory calculation has been performed to explore the solvation effect on heteroatom-doped endohedral gold clusters that always have remarkable stabilities and tunable electronic structures. The solvation free energy of the M@Au clusters (M = Cr, Mo, W, Co, Rh, Ir, Cu, Ag, and Au) was found to be related to the charge distribution of the central doped-atom M and the outer Au cage. Moreover, the aqueous solvent was observed to be able to increase the adsorption capacity of M@Au to O following the activation of O through the charge transfer from M@Au to O, in which the transferred electrons occupy the π antibonding orbital of O. In addition, the water solvent can also improve the hydrogenation reaction of O to form OOH over M@Au, where the activation energy barrier for this process is very low with the participation of the solvent. Considering the importance of solvents in the liquid-phase synthesis of atomically precise clusters, these findings highlighted here could provide valuable theoretical guidance in potential applications of functional gold nanoclusters, especially in the liquid-phase cluster catalysis.