Seed Mediated Formation of Bimetallic Nanoparticles by UV Irradiation: A Photochemical Approach for the Preparation of “Core−Shell” Type Structures

Abstract

Bimetallic gold and silver particles, a core−shell type structure, have been prepared by a UV-photoactivation technique. The optical absorption spectra are recorded and compared with various absorption profiles due to Au−Ag particles described in the literature. Initially Au particles formed by UV irradiation, which act as the seed particles, catalyzed the reduction of added silver ion in the presence of UV light to yield bimetallic (Aucore−Agshell) particles. Preferential dissolution of Au particles by cyanide and TEM images of the particles corroborates the “core−shell” type configuration.