Transition-Metal-Ions-Induced Coalescence: Stitching Au Nanoclusters into Tubular Au-Based Nanocomposites.

Abstract

Rod-shaped assemblages of Au nanoclusters (AuNCs) can serve as self-templating solid precursors to produce tubular Au-based nanocomposites via the coalescence induced by transition metal ions. Specifically, when the AuNC assemblages react with transition metal ions with relatively high standard oxidation potentials such as Cu(II), Ag(I), Pd(II), and Au(III), a series of polycrystalline and ultrathin Au and Aux My (where M = Cu, Ag, and Pd) alloy hollow nanorods (HNRs) can be obtained with further reduction; these metallic products are evaluated for electrooxidation of methanol. Alternatively, the above transition metal ions-induced transformations can also be carried out after coating the AuNC assemblages with a layer of mesoporous SiO2 (mSiO2 ), giving rise to many mSiO2 -coated Au-based HNRs. Onto the formed AuPd0.18 alloy HNRs, furthermore, a range of transition metal oxides such as TiO2 , Co3 O4, and Cu2 O nanocrystals can be deposited easily to prepare metal oxide-AuPd0.18 HNRs nanocomposites, which can be used as photocatalysts. Compared with those conventional galvanic replacement reactions, the controlled coalescence of AuNCs induced by transition metal ions provides a novel and efficient chemical approach with improved element efficiency to tubular Au-based nanocomposites.