Bimetallic nanoparticle generation from Au − TiO₂ film by pulsed laser ablation in an aqueous medium

Bimetallic nanoparticle formation by applying pulsed laser ablation on the gold (Au) - titanium (TiO₂) film was demonstrated. Experiments were conducted at room temperature. Au and TiO₂ nanoparticles were mixed in different ratios and deposited as the starting material on silicon wafer plates, which were dried and placed in a beaker with distilled water. After a pulsed laser beam was applied, the collected aqueous solution products were analysed by ultraviolet–visible (UV–vis) spectrophotometry and characterised by scanning transmission electron microscopy (STEM) with energy-dispersive X-ray spectroscopy (EDS). The UV spectra indicated that the Au, TiO₂, and Au–TiO₂ nanoparticles were dispersed in the aqueous solution product. STEM-EDS images showed that spherical bimetallic nanoparticles containing gold and titanium were generated. A core of TiO₂ nanoparticles was found to be well surrounded by a shell of Au nanoparticles when colloidal Au and TiO₂ nanoparticles at a 1:1 ratio was used as the starting materials. The technique described here is simple and innovative, and this study enhances our understanding of bimetallic nanoparticle synthesis using a pulsed laser beam in a liquid environment.