Cobalt@silver bimetallic nanoparticles: Solution based seedless surfactant assisted synthesis, optical properties, and morphology

摘要

Simple solution based method was used for the synthesis of cobalt@silver bimetallic nanoclusters in presence of cetyltrimethylammonium bromide"(CTAB) at room temperature. In a first step, monometallic cobalt nanoparticles (cobalt nucleus), was obtained which acted as a seed for the growth of silver shell in a second step under potential deposition. The optical images, UV visible spectroscopic, transmission electron microscopic (TEM), scanning electron microscopic (SEM) data revealed that the formation of silver shell around the cobalt core and their thickness were strongly depends on the [W]. Surface resonance plasmon peak increasing with [Ag+] and a red shift was observed. Number of the particles decreases with [Ag+], indicating the number of the nucleation sites decreases, which in turn, provided the less sites to Ag+ ions reduction. The reduction of Ag+ ions occurred on the surface of Co-0 by under potential deposition. Growth of Ag-0 alone occurs on the surface of Co/Ag rather than forming more nucleation sites. The optical properties of as prepared Co@Ag nano composites are dominated by the metallic Ag. The absence of oxygen peak in the EDX spectra, confirmed the formation pure Co@Ag nanoparticles with no oxide, which might be due the strong capping actions of CTAB. (C) 2016 Elsevier B.V. All rights reserved.