Fabrication of optically tunable silica nanocapsules containing Ag/Au nanostructures by confined galvanic replacement reaction

Silica nanocapsules containing Ag/Au alloy nanostructures (SNCAs) are fabricated by galvanic replacement (GR) reactions between silver core nanoparticles within silica shells and aqueous HAuCl4 in a confined nano-space. The structure and morphology of the resulting SNCAs are diversified by controlling the relative amount of Ag/Au, exhibiting tunable optical absorptions in visible region. The GR reactions in a confined nano-space include alloying and de-alloying processes that determine the evolution of morphology and optical absorption of SNCAs.Graphical abstractSilica nanocapsules containing Ag/Au alloy nanostructures with tunable optical properties arefabricated by confined galvanic replacement reactions between silver core nanoparticles withsilica shells and aqueous HAuCl4 in a confined nano-space.