On the photocatalysis evolution of heteroatom-doped Ag₄M₂ nanoclusters

Atomically precise metal nanoclusters doped with one or more heteroatom of other metals have exhibited extraordinary catalytic properties. Here we report a series of thiolate-protected Ag₄M₂ (M is dopant Ni, Pd and Pt) nanoclusters that adopt a similar structural framework like a distorted hexahedron, in which four Ag atoms are located at the midpoints of four side edges and two metal heteroatoms reside on the centres of the top and the bottom planes. The opposite orders of the catalytic performances of the three catalysts for the photocatalytic degradation of the methyl orange and rhodamine B dyes are found, which is attributed to two different types of inter-molecular recombination mechanisms. In both photocatalytic systems, both the catalyst and the dye are visible-light active, and the inter-molecular recombination of the photo-excited hole in the catalyst and the photo-excited electron in the dye leads to charge separation across the system comprising the catalyst and the dye. The study represents an important step towards developing the precise tailoring of the composition and structure to control the physicochemical properties of metal nanoclusters.