Chemical and Morphological Evolution of Copper Nanoparticles Obtained by Pulsed Laser Ablation in Liquid

Abstract

Pulsed laser ablation in liquid (PLAL) is a promising method to prepare copper/copper oxide nanoparticles (NPs), with the liquid used being an important factor to control their properties. The roles of the species dissolved in the liquid in the course of NP formation during the PLAL as well as the effects of organic solvents in the stabilization of the colloids obtained remain a debate. The peculiarities of the formation and alteration of the particles in ethyl alcohol as well as the effect of low amounts of oxidizing and acid–base species on the composition, structure, morphology, and stability of the NPs in the water colloids are examined. The observed high resistance of Cu NPs toward deep oxidation in ethyl alcohol suspension is shown to be connected with a competitive adsorption mechanism rather than the formation of the carbon shell. Pulsed laser ablation (PLA) of copper in distilled water yields cubic Cu2O NPs, while low amounts of NaOH and H2O2 species change the transformation route of copper NPs in the colloids formed. In the case of H2O2, the primary formation of the sheetlike and flowerlike Cu­(OH)2 particles occurs in the course of PLA followed by their pseudomorphous transformation into CuO particles during the suspension aging. The presence of NaOH yields leaflike CuO mesostructures via the tetrahydroxocuprate anion mechanism. On the basis of the results obtained, the schemes for the formation of the particles are proposed.

Synthesis of Air-Stable Cu Nanoparticles Using Laser Reduction in Liquid

“…The formation of two distinct size distributions of Cu NPs strongly suggests the participation of two different reaction mechanisms [33], although specific identification of these mechanisms is beyond the scope of this work. Nevertheless, on the basis of the PLAL literature demonstrating that substantial control over Cu NP size and morphology can be achieved by changing solvent mixtures [27][28][29][30], we anticipate that further exploration of different solvents will enable better control over Cu NP sizes using LRL. Finally, we note that the catalytic activity of the LRL Cu NPs to PNP reduction is comparable to that reported for PLAL Cu NPs [30], despite the presence of a thick carbon shell around our NPs.…”

“…Hence, greener synthesis routes to Cu NPs are of primary importance. To address this need, pulsed laser ablation in liquid (PLAL) has been widely employed to generate Cu NPs [ 26 , 27 , 28 , 29 , 30 ]. In these syntheses, copper oxides are a major product when ablation is conducted in water [ 26 , 27 , 28 , 29 ], and Cu phases are only stable when the ablation liquid contains an organic solvent, such as acetone, methanol, or ethanol [ 28 , 29 , 30 ].…”

“…In PLAL of Cu metal in water, Cu oxides are formed due to the presence of OH· radicals in the laser plasma from water, dissolved O 2 , or both [ 28 ]. Oxide formation during PLAL can be hindered through the use of organic solvents [ 27 , 28 , 29 , 30 ], which also can result in the formation of a protective carbon shell around the Cu NPs [ 27 , 28 ]. On the basis of these results, we designed an air-free LRL synthesis route to Cu NPs using an isopropyl alcohol/methanol solvent mixture.…”

Highly Defective Dark Nano Titanium Dioxide: Preparation via Pulsed Laser Ablation and Application

“…The Nd:YAG laser LS2131M-20, LOTIS TII (Minsk, Belarus) was used for the LAL. The ablation was carried out in a 100-mL cylindrical reactor for 3 h. Then, the solution was dried in air at 60 • C. The initial sample was annealed in the temperature range of 200-1000 • C. Detailed equipment and the experiment on the preparation of nanopowders were described in [26,46] and Supplementary Materials.…”

“…The high-energy nonequilibrium LAL method is currently used to obtain a wide range of nanoparticles (NPs) [26][27][28][29] and for surface structuring [30,31]. The LAL also allows for the production colloids of dark titanium oxide.…”