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

Abstract

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.