Synthesis of nanoparticles using a pulsed electrical discharge in a liquid

Abstract

We used a pulsed electrical discharge in a liquid to obtain Cu-, WC-, and ZnO-containing nanoparticles. The effect of the discharge current and pulse duration on the morphology and phase composition of the synthesized material was studied by spectrophotometry, transmission electron microscopy, and x-ray diffraction analysis. We discuss possible mechanisms for nanoparticle formation in a discharge submerged in a liquid.

A review of plasma–liquid interactions for nanomaterial synthesis

“…Stimulated by the unique poperties and a great number of potential applications of novel carbon-related NMs, the simple method of discharge plasma in liquid was used in many experiments in last decades, by just modifying some part of the prototype, successes have been made in producing MWCNTs [280][281][282][283], carbon onions [52,[284][285][286], carbon nano horns [287,288], carbon NPs [117,118,[289][290][291][292][293][294][295], and graphene nanosheets [117,[296][297][298][299]. One example of these fabrications is presented in Fig.…”

Spectroscopic diagnostics for an electrical discharge plasma in a liquid

“…When using an arc discharge regime, the electrodes are consumed more slowly and their consumption is accompanied by heating of the liquid all the way to the boiling point temperature. Consequently, the particle production rate is always higher in the spark regime than in the arc regime [8]. The plasma luminescence pulse (the emission integrated over the spectrum was recorded) practically duplicates the current pulse in shape; the luminescence lifetime matches the duration of the corresponding current pulses in the arc and spark discharge regimes.…”

“…Advantages of the electrical discharge method for nanoparticle synthesis include: the possibility of controlling the parameters of the final products by varying the discharge regimes; the rather high throughput, with the possibility of scaling up the synthesis process (in this case, the refractory nature of the metals is not important); the relatively simple equipment needed in the reactor design; the uncomplicated process for preparation of the starting materials. Application of this method also makes it possible to significantly expand the variety of materials that can be obtained (metal powders, metal oxides and carbides, composite materials, particles of mixed composition) [8,9]. The conditions for synthesis of nanosized particles in a plasma may be more favorable than conditions in a gaseous medium [10].…”

“…The conditions for synthesis of nanosized particles in a plasma may be more favorable than conditions in a gaseous medium [10]. This is connected with the fact that generally particles in a plasma are charged and repulsion between particles of like sign limits their growth, promoting formation of a narrower final particle size distribution.Despite the promise shown by the electrical discharge method and the growing number of papers on nanoparticle synthesis in electrical discharges in a liquid [3][4][5][6][7][8][9][10][11][12], in the literature we can only find scattered papers directly studying the discharge itself that is used to obtain the nanoparticles. Nevertheless, such discharge characteristics as electron temperature and the concentration of atoms and electrons are important for optimizing the synthesis process and controlling the parameters of the synthesized particles.…”

“…In order to record the current characteristics of the discharge, shunts of resistance R arc = 0.00375 Ω for the arc discharge regime and R spark = 0.00075 Ω for the spark discharge regime were connected in series in the electrical circuit. The shunt signal was fed to an interference-resistant amplifier (10) and recorded by oscilloscope (9). A protection circuit ensured that the main discharge current was recorded, and eliminated electrical noise arising as a result of the action of the ignition module of the discharge power supply.…”