silver-coated gold (Ag/Au) composite nanoparticles are prepared in two step by a
seeding growth method. The absorption spectra of bimetallic nanoparticles prepared in
two steps suggested the formation of core–shell structure.
Figure 2. Schematic of plasma chemical formations MNPs and characteristic
silver nanoparticles prepared by discharge plasma/ trisodium citrate [6]
The one step plasma chemical synthesis of Au–Ag alloy of bimetallic particles
was obtained. For Au/Ag alloy of bimetallic particles the surface plasmon absorption
maxima appeared in between the peaks corresponding to pure silver and pure gold. The
surface plasmon absorption maxima for bimetallic nanoparticles changes linearly with
increasing of gold content in the alloy (Table 1).
NPs with a tunable plasmon resonance wavelength and demonstrating a high
intensity in the visible region were obtained by adjusting the molar ratio of Ag to Au
precursors. Experimental results show that blended Au/Ag NPs exhibit a solar
photothermal conversion efficiency of 29.11%, which lies between the values of pure
Au and Ag NPs under the same NP volume fraction due to the independently scatter
light of the Au and Ag NPs in this composite system.
The DPPH free radical scavenging assay, total antioxidant capacity, reducing
power assay, total flavonoid contents and total phenolic contents determination
confirmed that synthesised Ag,
Ag/Au
NPs
are potent antioxidant agents; can be used
as an effective scavenger of free radicals.
Silver and bimetalic nanoparticles-alginate
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