Facile synthesis of copper, nickel and their bimetallic nanoparticles: optical and structural characterization

This paper reports the synthesis and characterization of some spherical crystalline copper (Cu), nickel (Ni), and their bimetallic (Cu-Ni) nanoparticles (NPs) produced in deionized (DI) water via pulse laser ablation in liquid (PLAL) technique. XRD and SAED patterns showed the high crystallinity of the synthesized nanostructures with face-centered cubic structure. The TEM and HRTEM images revealed the nucleation of spherical nanocrystals with a size range of 2.5-25 nm, and no remarkable aggregation was seen. Some core-shell oxidized Cu and Ni nanostructures related to the dissolved oxygen in DI water were detected. The UV-Vis absorption spectra at different aging times showed that pure metal nanoparticles are more stable than bimetallic nanoparticles. Localized surface plasmon resonance (LSPR) absorption peaks were recorded at 645 nm and 596 nm wavelengths for Cu and Cu-Ni colloidal solutions, respectively. The PL emission peaks at shorter wavelengths indicated that synthesized nanoparticles are blue luminescent. The achievement of pure and spherical copper, nickel, and their bimetallic nanoparticles with enhanced optical properties could be beneficial for advancing photocatalysis and antibacterial activity.