In the present work, silver nanoparticles were prepared by using the extract of Camellia Sinensis. The extract contains phytochemicals which are mainly polyphenols acting as the natural reducing and stabilizing agents leading to the formation of uniformly dispersed and stabilized silver nanoparticles. The synthesis of silver nanoparticles was significantly influenced by the impact of the pH, as well as temperature conditions. It was found that at pH 5 and 25 °C, nanoparticles of different morphologies (spherical, polygonal, capsule) and sizes were formed. However, with the increase in temperature from 25 °C to 65 °C but at the same pH, these particles started attaining the spherical shape of different sizes owing to an increase in the reduction rate. Furthermore, for the reaction of the mixture at 65 °C, an increase in pH from 5 to 11 led to an increase in the monodispersity of spherically shaped nanoparticles, attributed to the hydroxide ions facilitated reduction. The prepared nanoparticles were investigated for their antibacterial activity using Nathan’s Agar Well-Diffusion method. It was found that AgNPs prepared at pH 9 and 65 °C demonstrated strong antibacterial activity against gram-negative Escherichia coli in contrast to gram-positive Staphylococcus aureus. In reference to the cytotoxic potency, the prepared AgNPs showed clear cytotoxicity for HeLa cells and showcased a close relationship between activity and concentration as evidenced by the decrease in the percentage (100 to 30%) of metabolically active cells up to 25 µM–75 µM concentration of silver nanoparticles.

This paper demonstrates homogeneous dispersion of Au, Ag and Cu nanoparticles (size ∼ 5, 11 and 13 nm) into the mesopores of 3-aminopropyltriethoxysilane modified SBA-15 for improved catalytic reduction of m-dinitrobenzene to m-phenylenediamine.

In the last decade, the whole scientific community has witnessed great advances and progression in the various fields of nanoscience. Among the different nanomaterials, zirconia nanomaterials have found numerous applications...

Piezoelectric energy harvester has attracted considerable attention as an independent power source for applications in biocompatible, implantable, and flexible electronic devices. However, the lacuna of getting enhanced piezoelectric response from flexible lead‐free polymer‐based composite persists in this field. Here, we present a detailed study on the electrical characteristics such as dielectric, ferroelectric, and piezoelectric properties of (PVDF)‐[0.5Ba(Zr0.2Ti0.8)O3–0.5(Ba0.7Ca0.3)TiO3]‐graphene oxide (GO) three‐phase composite films synthesized by solvent‐casting followed by a hot pressing method. Structural investigations reveal that the fraction of β‐phase of PVDF in all the composites is more than 65%. The dielectric constant of the composite increases up to the threshold value (0.16 wt% for GO and 0.08 wt% for rGO), and further loading causes a decrease in the dielectric constant. The composite with GO concentration of 0.16 wt% (G‐0.16) shows a dielectric constant of 25.6 with a loss tangent of 0.0498. In contrast, composite with reduced graphene oxide (rGO) concentration of 0.08 wt% (R‐0.08) are 24.3 and 0.0681, respectively, at 1 kHz. Remnant polarization and d33 value of G‐0.16 are 0.012 μC cm−2 and 11 pC N−1, respectively, which are six times and four times more than pure PVDF. The piezoelectric harvester from G‐0.16 produces an open‐circuit voltage of ~4 V and a short‐circuit current of ~1.6 μA with simple hand tapping, which is the highest among the compositions, makes it a suitable candidate for piezoelectric energy harvesting applications.

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