Electrochemical synthesis, characterisation and phytogenic properties of silver nanoparticles

Abstract

This work exemplifies a simple and rapid method for the synthesis of silver nanodendrite with a novel electrochemical technique. The antibacterial activity of these silver nanoparticles (Ag NPs) against pathogenic bacteria was investigated along with the routine study of optical and spectral characterisation. The optical properties of the silver nanoparticles were characterised by diffuse reflectance spectroscopy. The optical band gap energy of the electrodeposited Ag NPs was determined from the diffuse reflectance using Kubelka-Munk formula. X-ray diffraction (XRD) studies were carried out to determine the crystalline nature of the silver nanoparticles which confirmed the formation of silver nanocrystals. The XRD pattern revealed that the electrodeposited Ag NPs were in the cubic geometry with dendrite preponderance. The average particle size and the peak broadening were deliberated using Debye-Scherrer equation and lattice strain due to the peak broadening was studied using Williamson-Hall method. Surface morphology of the Ag NPs was characterised by high-resolution scanning electron microscope and the results showed the high degree of aggregation in the particles. The antibacterial activity of the Ag NPs was evaluated and showed unprecedented level antibacterial activity against multidrug resistant strains such as Staphylococcus aureus, Bacillus subtilis, Klebsiella pneumonia and Escherichia coli in combination with Streptomycin.

Biosynthesis of silver nanoparticles using Haloferax sp. NRS1: image analysis, characterization, in vitro thrombolysis and cytotoxicity

“…K = 0.89 is the Debye–Scherrer constant. The lattice strain, ε, were estimated using the Williamson–Hall (WH) plot, determined according to Singaravelan and Alwar ( 2015 ) using the following equation (Eq. 2 ).…”

Preparation and characterization of multi‐walled carbon nanotubes decorated with silver nanoparticles through ultraviolet irradiation reduction

“…In addition, the UV–visible absorption spectrum of Ag is closely connected with its structure and can directly reflect the size and shape of Ag NPs . According to Mie theory, spherical Ag NPs exhibit a single absorption peak; however, Ag NPs of other shapes, such as rods, triangles, dendrites and prisms, show two or three absorption peaks.…”

“…In addition, the UV-visible absorption spectrum of Ag is closely connected with its structure and can directly reflect the size and shape of Ag NPs. [30,31] According to Mie theory, spherical Ag NPs exhibit a single absorption peak; however, Ag NPs of other shapes, such as rods, triangles, dendrites and prisms, show two or three absorption peaks. Thus, the single peak at 422 nm of MWNT-Ag illustrates that Ag NPs on the surface of MWNTs have a spherical shape, which is in agreement with the analysis of the FE-SEM images of MWNT-Ag.…”

The Influence of Plasmonic Au Nanoparticle Integration on the Optical Bandgap of Anatase TiO2 Nanoparticles

“…In this study, the optical bandgap (Eg) of the as-prepared nanoparticles was determined using the Kubelka-Munk method (Singaravelan & Alwar, 2015). The optical bandgap energy was calculated according to the Tauc equation (Tauc, 1968), which can be expressed as follows:…”

“…Measurement of optical bandgap has been considered one of the key factors in determining the potential applicability of a particular semiconducting material such as TiO2 in various types of applications, including photocatalysis. Typically, highly crystalline anatase TiO2 nanoparticles would have a bandgap value in the range of ~3.2 (Singaravelan & Alwar, 2015). Nevertheless, recent studies have also reported that several factors, such as the crystallinity, presence of impurities, crystal defects, nanoparticle grain size, and oxygen deficiencies could often alter the bandgap value of a typical semiconducting material such as TiO2 (Hidalgo et al, 2007).…”