Adsorption of iodide and iodate on colloidal silver surface

‘Chemically pure’ silver colloids were prepared by laser ablated method to investigate their adsorption-induced spectral and morphologic changes, using UV–visible absorption, Raman and transmission electron microscopy (TEM) techniques, when nucleophilic different anions (IO3− and I−) were added into sols. It reveals that the adsorption of nucleophiles on silver surfaces leads to an excess negative charge in the metal interior and modifies both surface charge density and the Fermi levels of metal, which is responsible for the colloidal aggregation, reconstruction and appearance of new resonance absorption bands or with wavelength shift. In addition, two models regarding different adsorption effects of these two anions on silver surfaces were proposed to explain their variant spectral and TEM phenomena.