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The nickel ion containing Langmuir–Blodgett (LB) multilayer was prepared by transferring first dissolving nickel acetate and the solution was poured into a subphase of ultrapure water and stearic acid-chloroform. The resultant mixture was then spread onto a hydrophilic water or glass plate. Then the multilayer was converted into nickel ultrathin film after chemical reduction by sodium borohydride. The optimized parameters for monolayer formation, such as concentration of subphase, pH value, barrier speed and standing time, were determined by the measurement of the surface pressure–surface area (Π–A) isotherms. The expended areas after deposition with nickel ions inferred the interaction of stearic acid with nickel ion during the formation of monolayer at air–water interface. The optimized parameters for multilayer deposition, such as surface pressure and dipping speed were determined by the measurement of the transfer coefficient. The Fourier transform infrared spectroscopy (FTIR) was used to investigate the interactions of nickel ions with stearic acid at air–water interface and in nickel ion/stearic acid LB film, as well as the metal transformations of nickel ion in ultrathin film. The disappearance of peak at 1689 cm^-1 verified the interactions between stearic acid and nickel ion. The further reduction made the organic phase dissolve and remove from the multilayer mostly. The surface morphologies of the LB multilayer and ultrathin film after reduction were detected by atomic force microscopy (AFM). A uniform and flat surface of nickel ultrathin film within nanometer ranges were obtained after reduction. The particle sizes of nickel were approximately 50 nm.

This investigation aimed to explore the characteristics of reduced graphene oxide (rGO) through a comprehensive approach. The synthesis of graphene oxide (GO) began with a customized adaptation of the modified Hummer’s method, followed by subsequent chemical and thermal reduction processes. Chemical reduction involved the use of ascorbic acid, hydrazine hydrate, and sodium borohydride, while thermal reduction occurred at various temperatures in the presence of hydrogen. The study employed a diverse array of analytical techniques to unravel the structural and chemical intricacies of the material. X-ray diffraction (XRD) revealed significant changes indicative of structural transformations. Raman spectroscopy meticulously examined defects and layer formations. Scanning Electron Microscopy (SEM) visualized the evolutionary aspects of the material’s structure. UV–VIS spectroscopy is employed to analyze the optical bandgap of the sample, and the primary importance of this study lies in its application potential for solar cells.

Herein, we attempt to study the synthesis process of 3-mercaptopropionic acid (3-MPA) capped gold nanoparticles (Au-MPA) and to optimize the preparation of colorimetric sensor based on the localized surface plasmon (LSP) phenomenon compared to the citrate stabilized gold nanoparticles (Au-Citrate). Both Au-Citrate and Au-MPA were prepared using the reduction method. In our case, the product of Au-MPA shows red-wine color of solution with a plasmonic peak at 527nm, while Au-Citrate has a plasmonic peak at 519nm with the same color of the solution. Both particles have a spherical shape as validated by the TEM image with the average size of Au-Citrate and Au-MPA being 34nm and 51nm, respectively. Different peak values can be explained by the different size distributions and modified local refractive indices due to the adsorbed ligand on the metal surfaces. Vibrational frequency characterization shows shifting and broadening especially in the region of CO stretching as the result of carboxyl group interaction. Functionalization of AuNPs by the use of biocytin (Biotinylated-AuNPs) shows good stability as revealed with no significant change in the absorbance spectra compared to the AuNP capped by citrate or 3-MPA. The addition of various concentrations of avidin into the assay results in the color changes and the red-shift of the absorbance spectra due to the cross-link aggregation with an intermediate value in the sensing characteristic. This research provides preliminary studies for colorimetric colloidal sensor performances tunability by modifying the adsorbed ligand as the linker between the metal and the bioreceptor.

Silver nanoparticles have been synthesized from Poly(N-vinylpyrrolidone) (PVP)/ethanol solutions, and six different PVP to silver nitrate weight ratios (PVP:AgNO₃) are studied in reduction of silver nitrate in ethanol with the presence of PVP as a stabilizer. The produced silver nanoparticles showed strong plasmon resonance peak centered at around 405nm in UV-Vis spectra. The particle morphologies were also examined and compared under secondary electron microscopy (SEM) and transmission electron microscopy (TEM). Energy dispersion X-ray spectroscopy (EDX) was utilized to determine the formation of silver nanoparticles. We found that the particle size and morphology were strongly dependent on the PVP:AgNO₃ weight ratio. The average size of silver particles decreased from 19.25nm to 10.03nm as the weight ratio of PVP:AgNO₃ increased from 1:1 to 20:1.

Synthesis of bona fideN-confused phlorin derivatives through simple chemical reduction of N-confused porphyrin precursors using sodium borohydride, p-toluenesulfonyl hydrazide, etc. is described. Spectroscopic, X-ray diffraction analyses and DFT-assisted calculations of these species support the nonaromatic phlorin electronic structure.

Various methods for the synthesis of copper nanoparticles employing chemical, physical and biological techniques considering bottom-up and top-down methods synthesis have been studied. The properties of copper nanoparticles depend largely on their synthesis procedures. The results from various investigations performed by different scientists using these methods have been summarized. The applications, characterization techniques, advantages and disadvantages of each synthesis method are also the point of discussion. A detailed study of the results reveals that chemical reduction methods are most suitable for the synthesis of copper nanoparticles. Chemical reduction of copper salts using ascorbic acid (Vitamin C) is a new and green approach in which ascorbic acid is used both as the reduction and capping agent. This approach is the most effective and is also economical. Wide applications have been reported in various fields, including heat transfer, catalyst production, electronics and medicine at a commercial scale. This process is nontoxic, environment-friendly and economical. The applications, characterization techniques, advantages and disadvantages of each synthesis method have been presented.

Magnetic Ni micro/nanostructures with controlled morphology have drawn intensive attention due to their interesting physicochemical properties and potential applications in micro/nanodevices. In this study, one-dimensional Ni nanochains with an average diameter of about 140 nm were prepared by a magnetic-field-assisted chemical reduction of Ni²⁺ with hydrazine hydrate free of any template or surfactant. It was found that the morphology and the size of the Ni chains could be adjusted by changing the complexant used in the synthesis. The usage of surfactant in the synthesis would retard the firm connection of Ni nanoparticles and thus resulted in the formation of Ni nanochains consisting of loosely aggregated Ni nanoparticles. The magnetic measurement at room temperature indicated that the coercivity of the Ni sample reached 133.2 Oe, which was much higher than that of bulk Ni metal.

The efficient synthesis of reduced graphene oxide (RGO) nanosheets via chemical reduction process of exfoliated graphene oxide (GO) nanosheets was performed by introducing sodium oxalate (Na₂C₂O₄) as a reducing agent. To study the effects of the reduction time on the synthesized RGO, the GO was reduced within -1/2, 1 and 2 h for RGO-1, RGO-2 and RGO-3, respectively. The C/O atomic ratio of the synthesized RGO-3 has increased from 2.16 to 6.32 after reduction as determined by X-ray photoelectron spectroscopy (XPS). The morphology analysis of the RGO-3 was determined by high-resolution transmission electron microscopy (HRTEM) almost revealed the formation of single layer. The number of RGO layers decreases as the time of the reduction increases. Based on these analysis results, sodium oxalate plays an important role in the efficient removal of the oxygen containing groups in the GO to produce high quality of RGO.