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Abstract:
The treatment of a silver polycrystalline foil with a 1:100 NO/O2 mixture at atmospheric pressure and room temperature led to the formation of a AgNO3/Ag2O/Ag “sandwich” in which no sharp boundary between the superimposed layers could be detected. The morphology of the as obtained structure was studied by means of X-ray photoelectron spectroscopy and scanning electron microscopy. The upper layer consisted of AgNO3 crystals of average size between 0.1 and 0.4 μm. It is suggested that silver(I) oxide was the product of the oxidation of metallic silver, whereas AgNO3 resulted from the subsequent reaction of Ag2O with NO2 in the gas phase. The underlying Ag2O layer, which was characterized by a rough surface and a high porosity, could be characterized after uncovering it by selective dissolution of the AgNO3 in water at room temperature.