Controllable synthesis, characterization and optical properties of Ag@AgCl coaxial core-shell nanocables

Core-shell structures often exhibit improved physical and chemical properties. Developing a relatively general, facile, and low temperature synthetic approach for core-shell structures with complex compositions is still a particularly challenging work. Here we report a general chemical conversion route to prepare high quality Ag@AgCl coaxial core-shell nanocables via the redox reaction between Ag nanowires and FeCl3 in solution. The powder X-ray diffraction of the Ag@AgCl coaxial core-shell nanocables shows additional diffraction peaks corresponding to AgCl crystals apart from the signals from the Ag nanowire cores. Scanning electron microscopy and transmission electron microscopy images of the Ag@AgCl coaxial core-shell nanocables reveal that the Ag nanowires are coated with AgCl nanoparticles. The effect of the molar ratio of Fe:Ag on the morphology and optical absorption of the Ag@AgCl coaxial core-shell nanocables is systematically investigated. The result shows that the optical absorption of Ag nanowires decreases gradually and that of AgCl nanoparticles improves gradually with the increase of the molar ratio of Fe:Ag. The formation process of the Ag@AgCl coaxial core-shell nanocables has been discussed in detail. The present chemical conversion approach is expected to be employed in a broad range of applications to fabricate innovative core-shell structures with different compositions and shapes for unique properties. (C) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim