Influence of Different Percentages of Copper on the Size and Optical Properties of Ag-Cu Nanoparticles Formed by Wet-Chemical Method

In this work, Ag-Cu nanoparticles (with different percentages of copper, 10%, 25%, 50%, 75% Cu) were synthesized by wet chemical method. Copper(II) sulfate and silver nitrate were taken as metal precursors, ascorbic acid as reducing agent and anhydride maleic (MA) as a modifier. The prepared nanoparticles were characterized by means of X-ray diffraction (XRD) technique and scanning electron microscopy (SEM-EDAX), Fourier transform infrared spectroscopy (FT-IR) and UV-Vis spectroscopy. SEM indicated the formation of uniform spherical crystalline nanoparticle in a well distributed size and morphology. It can be seen from these pictures that the particle size decreased with increasing of the copper percent. When the molar ratio of Cu2ﰈ is 75/25 (>50%), mixture of the spherical and hexagonal nanoparticles was prepared. Three pronounced Ag diffraction peaks (111), (200) and (220) appeared at 2θ = 38°, 43.9° and 64.1°, respectively. The three most intense peaks of the XRD pattern of sample showed a slight shifting of the center of the diffraction peaks toward a lower angle. No shifting was observed in XRD lines with the increase of Cu2 to Ag ratio in the Cu2ﰈ mixed solution (> 50% Cu). Fourier transform infrared spectroscopy (FT-IR) showed that nanoparticles are coordination between oxygen atoms and nanoparticles, because functional unit C=O present in MA, shifts to 1652.69 cm-1 after embedding nanoparticles. The position of the surface plasmon resonance (SPR) absorption band on the nanoparticles could be shifted from 380-350 nm via the change of their percentage of Cu.