Fabrication of Pt nanoparticles by nanosecond pulsed laser ablation in aqueous solution of ethanol using KrF excimer laser

Abstract

The present paper presents the premiere synthesis of platinum nanoparticles (Pt-NPs) by pulsed laser ablation in aqueous ethanol solution (PLAL) using an excimer nanosecond KrF laser. The impact of the laser fluence, repetition rate (RR) and ethanol concentrations on the optical and morphological properties of the obtained Pt-NPs was investigated. The optical characteristics has been assessed by transmission spectroscopy in the UV/Vis region, and the issues associated to the volatile component’s evaporation are discussed. Detailed information on the morphological properties was acquired via High-Resolution Scanning Transmission Electron Microscopy (HR-STEM). Mean size values in the range of 1.7–2.45 nm with narrow standard deviations from ± 0.6 up to ± 1.1 nm, were established for the synthesized Pt-NPs, that showed a certain level of aggregation. The smallest mean size value, 1.7 nm, was found for the sample produced using 2.3 Jcm−2 laser fluence, 10 Hz RR in 60 % ethanol concentration. The narrowest size distribution (±0.6 nm) was achieved with the same laser fluence and RR in 80 % aqueous ethanol solution. In addition, the metallic character (Pt) of the atoms forming the NPs was confirmed by Direct Analysis in Real Time Mass Spectrometry (DART-MS). The formation of face-centered cubic phase for Pt-NPs with interplanar distances of 0.25 and 0.19 nm for (200) and (111) crystalline planes, respectively, was revealed by X-ray diffraction (XRD). These results are in good agreement with those from HR-STEM analysis, where similar interplanar distances were obtained for individual NPs.