Dynamics of formation and decay of supercritical fluid silver colloid under pulse laser ablation conditions

Synthesis of Supported Heterogeneous Catalysts by Laser Ablation of Metallic Palladium in Supercritical Carbon Dioxide Medium

“…First, as known by the example of laser ablation of silver [ 28 ], conducting the process at a low scCO 2 density (0.2 g/cm 3 ) leads to the formation of small Ag particles (several nm). Conversely, a higher fluid density (0.8 g/cm 3 ) fosters the formation of large particles and their agglomerates, which, due to their tendency to sedimentation, settles to the bottom and walls of the reactor.…”

“…The density of the scCO 2 medium affects the destruction of alumina particles in the laser focusing region. It can be assumed that under low-density conditions, i.e., with a more effective laser action [ 28 , 29 ], the process of disintegration of carrier particles proceeds more actively, which leads to a decrease in the number of large particles in the system. As the density of the fluid increases, the destruction of Al 2 O 3 significantly slows and the fraction of large particles (>250 μm) of the support remains predominant.…”

“…Machmudah et al [ 27 ] showed that the morphology and sizes of gold and silver nanoparticles obtained by laser ablation in scCO 2 and deposited on a silicon plate strongly depend on the properties of the CO 2 medium (pressure and temperature). It was found in [ 28 ] that an increase in the colloidal density of supercritical fluid from 0.24 to 0.82 g/cm 3 caused a strong decrease in the rate of formation of silver particles, aggregation of small particles, and their faster sedimentation. The formation of composites from gold and silver nanoparticles with a polytetrafluoroethylene–vinylidene fluoride copolymer obtained by laser ablation in the scCO 2 medium was described [ 29 ].…”

Two Approaches to the Laser-Induced Formation of Au/Ag Bimetallic Nanoparticles in Supercritical Carbon Dioxide

“…An important advantage of supercritical fluids is the ability to adjust the density and a number of other characteristics of the medium within a wide range by changing the temperature and pressure. This allows the ablation process to be controlled by selecting the optimal parameters of the medium, including during laser exposure [22]. The supercritical state of CO 2 is characterized by extremely low viscosity at the level of gases, and high mobility of molecules, which allows ablation products to penetrate into hard-to-reach cavities and pores of various materials.…”

“…This work is devoted to the development of approaches to the synthesis of Ag/Au BMNPs using the method of laser ablation of massive targets in supercritical fluid media. As in our first experiments on this topic [7,22], we used targets consisting of silver and gold plates. The scCO 2 medium was chosen as the working medium in which the production of nanoparticles occurred.…”