Preparation of silver nanoparticles/nanocomposites and their catalytic/antimicrobial activity
" width="22px">Скиба М. І. , Vorobyova V. I., Dontsova T. A.
Химия и современные технологии
Silver nanoparticles were prepared in aqueous AgNO3 solution by using of contact non-equilibrium low-temperature plasma and different stabilizer reagents: polysorbate 80 (Tween 80), sodium alginate, citrate, PVP, PVA as capping agent. AgNPs were characterized by UV-visible spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The average size of formed AgNPs is 20-65 nm.
The synthesized AgNPs showed significant antibacterial activity against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli, assayed using agar well diffusion method. The catalytic activity of the AgNPs was evaluated for the reduction of 4-nitrophenol using NaBH4 at room temperature. The effect of different synthesis parameters and the catalytic property of the NPs were examined. Silver NP has been decorated on SnO2 nanoparticles to structure the Ag-SnO2 composites by impregnation of SnO2 samples with as synthesized nanoparticles. The difference of structure and properties between SnO2 and composite was characterized by XRD, UV-vis spectroscopy, Brunauer. Emmett. Teller (BET) analysis. Compared to bare SnO2, the surface modified photocatalysts (Ag-SnO2) showed a red shift in the visible region. The photocatalytic activity was monitored via the degradation of rose bengal (RB) dye and the results revealed that Ag-SnO2 shows better photocatalytic activity than that of SnO2. No extra phase changes were observed after Ag doping. UV-visible spectroscopy measurements indicated that the band gap of 3.50 eV for pure SnO2 nanostructures, decreased to 3.29 eV after doping.
The antibacterial activity of the nanostructures against E. coli was evaluated and a continuous decrease of microbial count was observed. The microbial population decreased from 5·105 cfu/ml to 6·104 cfu/ml and 3.5·104 cfu/ml on SnO2 and Ag-SnO2 treatments, respectively.