Chemical composition of silver-copper nanoparticles prepared by femtosecond laser ablation in water and organic solvents for biomedical and catalytic applications

Bimetallic silver-copper nanoparticles (AgCu NPs) are of significant interest for biomedical and catalytic applications due to their antibacterial activity, tunable surface chemistry, and enhanced catalytic performance. Pulsed laser ablation in liquids (PLAL) offers a versatile, ligand-free route to produce stable colloidal solutions of such NPs. However, the influence of the liquid medium on the physicochemical properties of AgCu nanoparticles remains unexplored. Here, we report a systematic study of AgCu NPs synthesized by femtosecond PLAL of a hot-pressed AgCu target in deionized water, isopropanol, acetone, and acetonitrile. The obtained NPs are predominantly spherical, exhibit a lognormal size distribution with a mode diameter of 30 ± 10 nm, and display a distinct localized surface plasmon resonance centered at 560 nm. Energy dispersive spectroscopy (EDS) analysis reveals a systematic dependence of the Cu/Ag, Cu/O, and Ag/O ratios on the solvent type, demonstrating that the chemical composition and surface oxidation state of AgCu NPs can be effectively tailored by the choice of ablation medium. These findings establish solvent selection as a critical parameter for fine-tuning the properties of laser-synthesized AgCu NPs and provide a straightforward strategy to optimize their performance in biomedical and electrocatalytic applications.