Synthesis Of Crystalline Nanoparticles Research Articles

The effects of Ag-ions on the physiochemical characteristics and visible-light catalytic activity of ZnS nanoparticles

In this case of study, the pure and different weight percentages of Ag ions doped ZnS Nanoparticles were synthesized by beneficial solid-state reaction method. Further, the synthesized nanoparticle’s physiochemical properties were thoroughly examined by the appropriate characterization tools. The structural examination demonstrates that the synthesis of crystalline nanoparticles with an average crystallite size of 2.41 nm was reduced from 3.68 nm to 2.41 nm and increased further due to the influence of Ag-ions on ZnS matrix. The FT-IR investigation validated the Zn-S functional molecule presence. A considerable quantity of spherical-shaped nanoparticles with uniform distribution enhances the possibility of aggregation due to heterogeneous particle interactions. The optical research demonstrates that the bandgap wideness is decreasing due to Ag-ion interstitial secondary energy levels. Due to the limitations in charge carrier recombination caused by Ag-influences, the catalytic capability of ZnS nanoparticles under renewable sunlight irradiation is enhanced. As a result, the Ag-doped ZnS nano-catalyst degraded 95 % of the detrimental MO dyes within a short sun light irradiation period.

Synthesis of spinel cobalt oxide nanoparticles using a modified polymeric precursor method

Metal oxide nanoparticles have been raising increasing interest. In this work, spinel cobalt oxide (Co3O4) nanoparticles of around 29nm were synthesized using a modified polymeric precursor method. This method is based on the complexation of polyacrylate and cobalt ions in aqueous media by a chelation reaction, resulting in the synthesis of crystalline nanoparticles, confirmed by X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM). Some advantages of this technique are the fast, simple and efficient synthesis of nanoparticles after only 2h of thermal decomposition at 480°C and elimination of the aging step, which is an essential step in polymeric precursor-based methods such as sol–gel.

Green synthesis and characterization of silver nanoparticles using Lantana camara leaf extract.

In this work, we have investigated on Lantana camara mediated silver nanoparticles (AgNPs) with different leaf extract (LE) quantity for the evaluation of efficient bactericidal activity. The AgNPs were prepared by simple, capable, eco-friendly and biosynthesis method using L. camara LE. This method allowed the synthesis of crystalline nanoparticles, which was confirmed by X-ray diffraction (XRD) and selected area electron diffraction (SAED) patterns. The X-ray photoelectron spectroscopy (XPS) analysis confirmed the formation of metallic silver and elucidates the surface state composition of AgNPs. UV-vis spectra of AgNPs and visual perception of brownish yellow color from colorless reaction mixture confirmed the AgNP formation. Involvement of functional groups of L. camara leaf extract in the reduction and capping process of nanoparticles was well displayed in Fourier transform infrared spectroscopy (FTIR). Decrement of particle size with an increment of leaf extract volume was evident in AFM, TEM images and also through a blue shift in the UV-vis spectra. The rate of formation and size of AgNPs were dependent on LE quantity. Meanwhile, these AgNPs exhibited effective antibacterial activity with the decrement of particle size against all tested bacterial cultures.

Efficient nanoparticle synthesis

Nanoparticles are essential building blocks for many energyrelated applications, ranging from lithium ion batteries, catalysis, and photocatalysis to electrochromic windows. The ability to synthesize nanoparticles with well-defined size, shape, and structure is critically important. In recent years, there have been two main trends to improve the efficiency of nanoparticle synthesis by use of microwave or microfluidic reactors.1, 2 Microwave reactors provide a higher nanoparticle yield in shorter reaction times than conventional batch reactors,1 and microfluidic reactors have the separate advantage that reaction conditions, such as heat and mass transfer rates, can be independently controlled for small volumes of reaction solution.2 Integrating such miniaturized reactors with microwave heaters would combine the advantages of both and so improve nanoparticle synthesis. Several such devices have been developed for aqueous solutions, which are suitable for biochemical applications such as heating a polymerase chain reaction.3 However, water is not a suitable solvent for low-temperature, low-pressure synthesis of crystalline nanoparticles. Recently, colleagues and I have developed a microfluidic-microwave device, operating at 700–900MHz, which allows precise tuning of the temperature of non-aqueous solvents such as benzyl alcohol, n-butanol, and ethylene glycol.4 We used two independent non-contact methods to determine the temperature of benzyl alcohol droplets flowing in fluorocarbon-based oil. Infrared temperature imaging provided quantitative information about the microwave heating of the benzyl alcohol droplets and heat transfer from the droplets: see Figure 1. Additionally, we measured the microwave heating of the benzyl alcohol droplets by fluorescence imaging with high temporal resolution. We can heat the benzyl alcohol droplets to 50C in 15ms. We used our microfluidic-microwave device to synthesize tungsten oxide nanoparticles within benzyl alcohol droplets using the synthesis protocol for a conventional reaction in oil bath. Figure 1. Top: A 2D temperature map measured at the surface of the microwave-microfluidic device with an IR camera. Bottom: A schematic of the microfluidic-microwave device. (Copyright the Royal Society of Chemistry.4)

Low Temperature Synthesis of Nanocrystalline ZnFe<sub>2</sub>O<sub>4</sub> Powders

Advances in nanoscale electronics require superior ceramic powders, preferable prepared with techniques for the direct synthesis of crystalline nanoparticles. Zinc ferrite (ZnFe2O4) nanopowders were prepared by co-precipitation method, from nitrate precursors. Crystalline powders having the single-phase cubic spinel structure were directly synthesized at temperature ≥80°C in the presence of NaOH. The obtained powders are agglomerated with ultra-fine crystallites having the average crystallite size about 3-4 nm.