Estimation of Surface Oxide on Surfactant-Free Gold Nanoparticles Laser-Ablated in Water

Abstract

Surfactant-free gold nanoparticles were prepared by laser ablation of a gold metal plate in water. The nanoparticles were characterized by absorption spectroscopy, ζ-potential measurements, and XPS spectroscopy. The nanoparticles are negatively charged because the surface atoms are partially oxidized to Au-O -, according to the literature by Sacher and co-workers (J. Phys. Chem. B, 2004, 108, 16864). We further examined electrostatic interactions between nanoparticle and cationic surfactants. It was found that the surfactant cations attach to the particle surface, neutralizing the particle charge. Taking advantage of the electrostatic interactions, we estimated that 3.3-6.6% of the surface gold atoms was oxidized in water.

Pulsed-Laser Ablation of Au Foil in Primary Alcohols Influenced by Direct Current

“…First of all, Au nanoparticles are preferred by many applications as it has been well documented in Introduction. Furthermore, they do not undergo surface oxidation as easily as Ag and/or Cu nanoparticles (Muto et al, 2007). Primary alcohols as ablation medium have been chosen because of a good stability of Au nanoparticles in ethanol and other aliphatic alcohols as reported in the literature many times (Amendola et al, 2006(Amendola et al, , 2007Amendola & Meneghetti, 2009;Compagnini et al, 2002Compagnini et al, , 2003.…”

Surfactant-free solution-based synthesis of metallic nanoparticles toward efficient use of the nanoparticles’ surfaces and their application in catalysis and chemo-/biosensing

“…Owing to electrostatic repulsion, there was a significant reduction in their size when different salts were used (7 ± 5 nm for 10 m m KCl, 5.5 ± 4 nm for 10 m m NaCl, and 8 ± 5 nm for NaOH at a pH of 9.4). It has been reported 3.3 -6.6 % of the gold atoms on the surface were negatively charged [100] . More recently, Co and Au nanoparticles have been synthesized by femtosecond-long laser ablation in various liquids (n-hexane, diethyl ether, toluene, 2-propanol, acetone, and methanol) in the absence of a surfactant to investigate the effect of the liquids on the size of the nanoparticles [102] .…”

Synthesis and characterization of gold/water nanofluids suitable for thermal applications produced by femtosecond laser radiation

“…Moreover, femtosecond radiation, compared to laser ablation at relatively long time scales (e.g., nanosecond and picosecond), can effectively minimize the laser-plume interaction and reduce the heat affected zones, 34,35 thus obtaining the highest quality and best shape-controlled NPs. Moreover, gold NPs generated by laser ablation in liquids are electron acceptors because of surface atom oxidation, 36,37 which produces a relatively high particle surface charge. The NPs attract oxygen species, and the resulting surface charge triggers electrostatic repulsion providing stable colloids of metallic particles in aqueous media without the need for any stabilizer.…”