experimental data, it was determined that the average size of plasmochemically
prepared particles depends on the initial concentration of silver ions in the solution and
equals 36.5–60.1 nm for 0.25–3.0 mmol/l.
Table 1 The yield of silver nanoparticles depending on the synthesis method
Synthesis method
Yield of nanoparticles, %
Contact nonequilibrium low-
temperature plasma
without the stabilizer
95.10
in the presence of AlgNa
97.17
Chemical deposition
without the stabilizer
93.9
in the presence of AlgNa
93.9
Photochemical deposition
20.0
The kinetics of chemical conversion in aqueous solutions of silver nitrate under
plasma treatment conditions in a gas-liquid plasmochemical batch reactor is
investigated. The curves of Ag
+
dependence on duration of plasmochemical treatment
of solutions and initial concentration of silver ions are given. It is found that the process
of plasmochemical formation of silver nanoparticles is the second-order reaction [5].
The rate constant of formation of silver nanoparticles is k=0.07–1.53 mol
-1
∙dm
3
∙min
-1
depending on the initial concentration of silver ions.
It is found that in the plasma-chemical synthesis of silver nanodispersions, the
introduction of different stabiliser agents (sodium alginate, trisodium citrate, polyvinyl
alcohol, polyvinyl pyrrolidone) into the reaction mixture increases the yield of silver
nanoparticles and allows synthesizing stable colloidal silver solutions. The effect of
reaction conditions such as the concentration of silver ions, molar ratio Ag
+
/stabiliser
agents, irradiation time on the synthesis of AgNPs was studied. It is shown that the
formation of silver nanodispersions under plasma discharge is characterized by the
presence of the peak λ
max
=378–480 nm. The formation of silver nanoparticles was
confirmed by the X-ray diffraction analysis (Table 2, Fig. 2).
Table 2 Characteristics of monometallic and bimetallic nanoparticles prepared
in plasma treatment conditions
Type NPs
Stabilization agent
SPR, nm
Size
distribution,
nm
Zeta potential,
(mV)
Ag
–
400-480
20-70
– 14.2 to –10.1
sodium alginate
400-440
20-70
–32.8 to –39.3
trisodium citrate
380-450
15–75
–28.2 to – 32.0
polyvinyl alcohol
400-440
20-58.4
–37.8 to – 42.1
polyvinyl pyrrolidone
378-400
7–150
–20.1 to – 21.3
Au/Ag alloy
polyvinyl alcohol
485-490
5–70
–25.1 to – 27.2
Bimetallic silver/gold nanoparticles have been prepared using low-temperature
contact non-equilibrium plasma in one and two steps. Gold-coated silver (Au/Ag) and
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