Preparation of anisotropic AgNWs/PVA/Ag2S nanocomposites via a vapor-phase sulfidation process.

This study used a modified polyol technique to synthesize silver nanowires (AgNWs), which were subsequently mixed with polyvinyl alcohol (PVA) polymer and air-dried under ambient conditions. As a result, AgNWs/PVA nanocomposites with a concentration of 2% were prepared by a casting process. After that, the upper surface of the produced samples was treated with H2S gas, as a result of which asymmetric structures were formed depending on the gas concentration, exposure time and penetration into the layers. The structural, morphological, and optical properties of these asymmetric structures were analyzed. Changes in the sample structure were studied using X-ray diffraction (XRD), their optical properties were studied using ultraviolet-visible (UV-Vis), Raman spectroscopy, and their morphology using Transmission electron microscopy (TEM). A simple technique involving H2S gas was used for the sulfidation process of the samples, marking the first exposure of AgNW/PVA nanocomposites to such treatment. Examination of the structural and optical properties of the surfaces revealed clear differences in their physical properties after sulfidation. These obtained results were also supported by TEM images. Finally, the successful production of AgNWs/PVA/Ag2S anisotropic structure was achieved by this method.

Effect of sulphidation process on the structure, morphology and optical properties of GO/AgNWs composites.

In this study, composite materials composed of graphene oxide (GO) synthesized by a modified Hummers' method and silver nanowires (AgNWs) synthesized by a modified polyol method were prepared. The prepared composites were subjected to sulfidation under the influence of H2S gas. Structural changes in the samples were evaluated using X-ray diffraction (XRD). The binding nature of the composite was characterized using FT-IR spectroscopy. Optical properties and band gap values were investigated using ultraviolet-visible (UV-Vis) spectroscopy. The morphology of the composites was analyzed by transmission electron microscopy (TEM). A simple method using H2S gas was applied for the sulphidation process of the samples. The sulfidation process was successful under the influence of H2S gas, resulting in an increased distance between the GO layers and a decrease in the band gap value for the composite post-sulfidation. In addition, AgNWs were observed to decompose into Ag2S nanoparticles under the influence of H2S gas. It was determined that the value of the band gap of the sample changes because of sulphidation.

Features of structure and optical properties GO and a GO/PVA composite subjected to gamma irradiation.

In this study, a modified Hummers' method was employed to prepare graphene oxide (GO), which was then mixed with polyvinyl alcohol (PVA) polymer at varying weight concentrations (1 wt% and 5 wt%). The prepared GO and GO/PVA nanocomposite films were subjected to gamma (γ) radiation at different doses (10, 500, and 1500 kGy) to analyze the effects on their structure and optical properties. The structural changes in the nanocomposites were analyzed using X-ray diffraction (XRD), allowing for the determination of any alterations resulting from exposure to radiation at different doses. Furthermore, elemental analysis was conducted using an energy-dispersive spectrometer (EDS) to gain insights into the elemental composition of the samples. The optical properties of the samples were investigated using ultraviolet-visible (UV-Vis), Fourier-transform infrared (FTIR), Raman spectroscopy, and scanning electron microscopy (SEM). These analysis methods provided valuable information regarding any changes induced by gamma radiation. Notably, in the study, the decomposition and oxidation of residual graphite were observed under the influence of γ radiation. One noteworthy finding was the decrease in the band gap value of the samples with increasing gamma radiation. This observation indicates that the radiation exposure influenced the electronic properties of the nanocomposites, leading to changes in their optical behavior. The Raman spectra clearly showed that the strength of the G and D bands dropped at low doses and reached a maximum at higher doses. FTIR intensity varies with radiation, indicating the separation of oxygenated groups during exposure. The SEM images revealed that as the radiation dose increases, the disintegration of GO on the polymer's surface happens, and at the greatest dose, the distribution of GO and PVA in the pores occurs due to the heating action of radiation.

Cobalt chromium-layered double hydroxide, α- and ß- Co(OH)2 and amorphous Cr(OH)3: synthesis, modification and characterization.

Cobalt-chromium layered double hydroxide (CoCr LDH), α- and ß- Co(OH)2 and amorphous Cr(OH)3 have been synthesized under different reaction conditions. The obtained CoCr LDH was modified by stearic acid (SA) and sodium stearate (SS). The obtained samples have been characterized by X-ray diffraction (XRD), Scanning electron microscope (SEM), Ultraviolet-visible- (UV-Vis), Fourier transform infrared- (FTIR) and Energy-dispersive X-ray- (EDX) spectroscopy. The influence of reaction conditions on product composition, structural and optical properties of the samples have been discussed in detail. The basal spacing of CoCr-LDH increased from 7.366 Å to 7.428 Å and 25.214Å after the intercalation by stearic acid and sodium stearate, respectively. The average particles size by SEM analyze was estimated to be approximately 100-150 nm and 30-50 nm for CoCr-LDH0.6M(90°C) and CoCr-LDH0.6M(90°C)/SS nanostructures, respectively. Mixed hydroxides like α- and ß- Co(OH)2 have been obtained along with LDH at lower pH value (pH ∼ 7). The number of diffraction peaks corresponding to ß-Co(OH)2 has increased with relatively decreasing of Co2+ ions in the reaction medium. At high chromium concentrations (Co2+:Cr3+ = 1:3 and 1:5), amorphous Cr(OH)3 were formed in the experiment.