Atomically precise copper dopants in metal clusters boost up stability, fluorescence, and photocatalytic activity

Abstract

The structurally precise alloy nanoclusters have been emerged as a burgeoning nanomaterial for their unique physical/chemical features. We here report a rod-like nanocluster [Au12Cu13(PPh3)10I7](SbF6)2 (Au12Cu13), which was generated through a transformation of a [Au9(PPh3)8]3+ intermediate in the presence of CuI, unveiled by time-dependent UV-vis spectroscopy, electrospray ionization mass spectrometry as well as single crystal X-ray diffraction. Au12Cu13 is comprised of two pentagonal bipyramids Au6Cu units and a pentagonal prism Cu11 unit, where the copper and gold species are presented in +1 and 0 chemical states. The Cu-dopants significantly improved the stability and fluorescence (quantum yield: ~34%, 34-folds of homo-Au25(PPh3)10Br7). The high stability of Au12Cu13 is attributed to the high binding energy of iodine ligands, Au-Cu synergistic effects and its 16-electon system as an 8-electron superatom dimer. Finally, the robust Au12Cu13 exhibited high catalytic activity (~92% conversion and ~84% methyl formate-selectivity) and good durability in methanol photo-oxidation.