Journal of Nano Structures
Volume:10 Issue: 3, Summer 2020

We prepared samples including nanoparticles of ZnS via co-precipitation method in room temperature and with microwave heating using water as a “green” solvent. The procedure was repeated with various natural surfactants. XRD and SEM analysis was performed to determine the nanostructural and morphologic characteristics of nanoparticles. The mean diameter less than 100 nm for ZnS particles showed that there was well-formed pure nanostructure. SEM analysis disclosed that temperature and type of surfactant will affect the nanostructures and so we can control the nanostructure and particle size with changing such parameters. With combining of pure Carbon and ZnS nanoparticles in various proportions, Carbon - ZnS nanocomposites was prepared using microwave heating. SEM and FT-IR analysis was performed on these nanocomposites to compare them with pure Carbon and ZnS nanoparticles. We also assessed the photocatalytic potential of prepared nanocomposites using acidic and neutral pH methyl orange and Congo red solutions under UV- IR radiation. This study confirms that these nanocomposites can be used as photo-catalysts for water refinery in home and industries.

In this study, a series of Mg0.3Cu0.2Zn0.5Fe2-xLaxO4 ferrite nanoparticles with x= 0 to 0.15, with step 0.015 were synthesized by sol-gel auto combustion method. The effect of rare earth La which was substituted for Fe3+, on the structural, microstructure and magnetic properties of prepared samples were investigated. The structural characteristics of samples were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The XRD patterns showed the formation of cubic spinel structure for all samples without any extra peak. The microstructural evaluations showed homogeneous particles and also revealed that their size are about 36 – 51 nm. The magnetic properties of samples were investigated using vibration sample magnetometer (VSM) and Impedance analyzer. Results show that On La substitution, the values of saturation magnetization (MS) were slightly decreased. The real part of permeability as well as Curie temperature were dramatically decreased with increasing x.

During the last decade, mechanochemical synthesis, which can provide the nanostructured constituents, has been considered as an alternative technique to the conventional thermite reactions to produce the metallic-ceramic composite. Detection of the reinforcement in such nanocomposite powders has been provided challenges as a result of low volume fraction and high induced lattice strain. In this work, the mechanochemical reaction of a non-stoichiometry Fe2O3-Al system (Fe2O3+Al+Fe powder mixture) was performed to produce the Fe3Al-30 vol.% Al2O3 nanocomposite. The progress of the reaction was followed by X-ray diffractometry (XRD) and transmission electron microscopy (TEM). XRD analysis of mechanochemically synthesized Fe3Al-30 vol.% Al2O3 nanocomposite showed no evidence of the produced Al2O3 phase, whereas TEM analysis revealed the crystalline Al2O3 phase. The X-ray absorption by component higher mass absorption coefficient (Fe3Al matrix) in highly strained nanocomposite leads to a decrease in the diffraction intensity of components with lower mass absorption coefficient and with low volume fraction (Al2O3). High-temperature heat treatment lead to crystallite growth as well as lattice strain reducing, which resulted in the capability of detection of Al2O3 by XRD analysis.

Solid oxide fuel cell (SOFC) is being developed all over the world at present as a future energy conversion device. The alternative anode materials are also being studied in order to develop efficient low temperature SOFCs (LTSOFCs) operating below 800o C. Ni‐based cermets are still the most promising anode materials and some targeted modifications are needed to improve the coking resistance and to enhance their electro-catalytic activity relatively at low temperature (~600 – 700 oC) range. Present work is aimed to develop alternate anode materials such as, NiO-Ce0.9Gd0.1O2-δ-Ce0.9Y0.1O2-δ, NiO-Ce0.8Gd0.2O2-δ-Ce0.8Y0.2O2-δ, NiO-Ce0.9Gd0.1O2-δ-Ce0.9Sm0.1O2-δ, NiO-Ce0.8Gd0.2O2-δ-Ce0.8Sm0.2O2-δ, NiO-Ce0.9Gd0.1O2-δ and NiO-Ce0.8Gd0.2O2-δ for by simple chemical precipitation route and characterize them towards application in SOFC systems. The precursor materials used in this synthesis were cerium nitrate hexahydrate, gadolinium nitrate, yttrium nitrate, samarium nitrate [as basic materials] and sodium hydroxide [as precipitator material]. C-TAB (cetyl trimethylammonium bromide) was used as a surfactant in order to avoid the agglomeration of the nanoparticles. The influence of Gd, Y and Sm doping on the phase structure development of ceria was investigated. The prepared anode materials were characterized by TGA, XRD, FTIR, particle size analysis, SEM and EDAX. The electrical characteristics of the materials were studied by electrochemical impedance spectroscopy. The results obtained were discussed in order to use the materials as alternate anode materials for SOFCs.

Zeolite has presented a unique crystalline structure with an excellent exchange capability formed by Al-O-Si, which it can be used as a good surface for dispersed metal particles. In this work, rapid synthesis of zeolite Y-platinum nanoparticles by ultrasonic treatment was studied. The structure and morphology of the prepared zeolite Y-platinum nanoparticles were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Energy-dispersive X-ray spectroscopy (EDS), Brunauer-Emmett Teller (BET), and EDS mapping analysis. In this work, we successfully developed a rapid and green method for the synthesis of zeolite Y and zeolite Y-platinum nanoparticles with uniform small crystals and high purities by the use of ultrasonic irradiations. The use of ultrasound irradiation has proved to be an environmentally sound, time and cost effective approach for various organic and inorganic compounds. Also, it is an excellent technique for the adherence of nanoparticles to a large variety of substrates. Investigation of the electrochemical characteristics of the prepared Z-Y-Pt NPs was carried out by the use of cyclic voltammetry (CV) test and it displays ratio of jf/jb=1.10 that can be suitable for redox reaction in fuel cell.

At the first step calcium ferrite nanostructures were synthesized via a facile precipitation method in the presence of green and compatible capping agent such as starch, poly vinyl pyrrolidone and glucose in solvent of water. Then cerium oxide nanoparticles and CaFe2O4-CeO2 nanocomposites was made by a fast chemical procedure. The effect of temperature in nanoparticles and nanocomposites concentration and precipitating agent on the morphology and particle size of the products was investigated. The prepared products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared (FT-IR) spectroscopy. Also the crystalline size of nanoparticles was calculated by Debye-Scherrer formula. Vibrating sample magnetometer (VSM) shows the ferromagnetic property of the ferrite nanostructures. The photocatalytic behaviour of CaFe2O4-CeO2 nanocomposites was evaluated using the degradation of three azo dyes (acid black, acid violet and acid blue) under ultraviolet light irradiation. The results introduce a nanocomposite with applicable magnetic and photocatalytic performance.

Isatin based materials can exhibit a wide range of biological activities including antimicrobial, antiviral, antifungal, anthelmintic, antitumor, anti-HIV, anti-inflammatory, antidepressant, antioxidant, anticonvulsant, antitubercular, analgesic, and central nervous system depressant activities. In this study, four compounds containing 5-Fluoro-isatin thiosemicarbazone with methoxyphenyl or methoxyphenyl in different positions and zinc complexes were evaluated based on their biological activities. Compound 2 was the strongest compound affecting gram-negative bacteria compared to the other compounds. Also, this compound indicated better antimicrobial activity than positive control antibiotics. Besides, compound 3 was the only compound that inhibited the growth of Salmonella spp. such as Salmonella enteritidis ATCC 13076 and Salmonella typhimurium NRRLE 4463. 5-Fluoro-Isatin thiosemicarbazone and its derivatives also showed DNA protection property from moderate to good protections. Among them, compound 4 displayed the highest DNA binding affinity. These compounds possessed a capacity for utilization as drugs or drug additives based on their effects on bacteria strains and DNA binding affinity.

Ferrite chromite (FeCr2O4) powders have been synthesized by a hydrothermal method using various alkaline agents and capping agent. For the first time, nanostructured Ferrite chromite was synthesized with utilizing tetraethylenepantamine as a new alkaline agent. The SDS, PVP and PEG as stabilization agent and capping agent in presence of TEPA as alkaline agent were employed to prepare of the Ferrite chromite. The structural character of as-synthesized powders was characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive X-ray microanalysis (EDX). The results indicate that the as-obtained powders are pure. The electronic properties of as-synthesized powders was characterized by UV–Vis diffuse reflectance analysis (DRS), which shows the as-obtained sample has a significant absorption in the UV region. The photocatalytic degradation of the rhodamine B, methyl orange, murexide and methylene blue as water pollutants were investigated. According to the results, photocatalytic activity of FeCr2O4/Ag nanostructures were better than of other samples and degradation percent of rhodamine B as a cationic pollutant was more than the other dyes.

Developing a novel sensor for analysing of ascorbic acid present in food items and nutraceuticals is been very important research topic for materials scientists, medicine and food researchers. In the present work, we demonstrate the detection of an ascorbic acid (AA) by using an electrochemical sensor made from novel rGO@ZnO nanocomposite material. We synthesized a ZnO-nanoparticle-decorated reduced graphene oxide composite (rGO@ZnO) using a one-pot hazard free green-hydrothermal method. Multi characterization techniques like X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy and Raman spectroscopy, were precisely used to understand the structure and properties of the rGO@ZnO nanohybrid. Finally, the synthesized rGO@ZnO nanohybrids were utilized to fabricate low cost screen printed electrode (SPE) electrochemical sensor for highly sensitive detection of ascorbic acid (AA). The observed electrochemical sensing results indicate wide linearity from 0.1 mmol to 1.5 mmol with good repeatability and reproducibility. The results confirm that the synthesized novel rGO@ZnO nanohybrids exhibit excellent electrocatalytic activity towards AA with high stability and sensitivity.

IIn this paper, we proposed a short channel Silicon on Insulator Metal-oxide Semiconductor-Field-Effect-Transistor (SOI-MOSFET), in which a thin layer of n+-type doping has been expanded from top of its entire source region into the channel and also a proportionally heavily p-type retrograde doping has been implanted in its channel, close to the source region. Due to source doping expansion in the channel, we call this structure as Source Expanded Doping Silicon on Insulator (SED-SOI) structure. This expanded n+ doping increases the carrier concentration in the source, which can be injected into the channel. Moreover, it increases the amount of carriers, which can be controlled more effectively by the gate electrode. These two advantages enhance both ON state current and transconductance in the device more than 1.9 mA and 5 mS, respectively. Engineered p-type retrograde doping profile causes impurity scattering and this reduces electron mobility in the depth of the device channel, which in turn OFF current decreases down to 0.2 nA. An immense comparison among our proposed device and a conventional structure (C-SOI) shows that it has better performance in terms of Ion/Ioff ratio (>9.5×105), subthreshold swing (75 mV/dec), leakage current, breakdown voltage, hot carrier injection and DIBL. Our analysis demonstrate that SED-SOI transistor can be an excellent candidate for both low power and high performance applications.

Some researchers have reported the successful experiments to produce nanocellulose-based filaments by several spinning methods, including wet spinning and dry spinning. The addition of nanocellulose to the composites was found to improve the mechanical and thermal properties of produced filaments or continuous fibers. However, there are several parameters of spinning that needs to be considered to achieve better quality of filaments, including high aspect ratio of nanocellulose, low viscosity of dope (low solid content), high shear rate in the spinneret, and high draw ratio. This review article focuses on brief explanation of cellulose structure and how to isolate nanocellulose, nanocellulose-based filaments by wet spinning and dry spinning methods, characteristics of wet and dry spun fibers, as well as parameters that affect spinning process. For example, the strength of filament was attributed to the aspect ratio or slenderness and crystallinity of nanocellulose. Further details of the potential application of nanocellulose for filament production is presented here as the reference for application in textile, medical, and other fields.

In this study, carbon nanotubes (CNTs) were deposited directly on impregnated Fe/carbon paper (CP) substrate (CNT/CP) utilizing chemical vapor deposition (CVD) process with the aim of using them as electrocatalytic electrode. The influence of wet impregnation conditions and CVD growth parameters on the characteristics of CNTs was investigated. Field emission scanning electron microscopy (FESEM), Energy dispersive spectroscopy (EDS), Transmission electron microscopy (TEM) and Raman spectroscopy were applied to characterize nucleation, growth and morphology of CNTs on CP. Measurement of Contact angle (CA) determined 125.9 and 145.0 ⁰C for CP and CNT/CP that displayed an increase in water repellence and degree hydrophobicity of CNT/CP to 15% than CP. Electrochemical impedance spectroscopy (EIS) analysis indicated the reduction of electrode charge transfer resistance from 5000 ohm value from CNT/CP to ohm value for CP that shows the increment in electrical conductivity of CNTCP. Half-cell test analysis represented that the improvement of performance and the increase of power density to ⁓8 % for Pt/CNT/CP compared to commercial catalyst Pt/C/CP (20 wt%) even with about 42% less Pt loading, can be attributed to strong adhesion of in-situ CNTs to the CP and lower agglomeration of CNTs along with outstanding electrical and thermal conductivity of CNTs. The obtained results indicated that the proposed nanostructure serves as a promising candidate for many technological applications specially carbon nanotube-supported catalyst.

We have fabricated novel MnFe2O4@ZnO–GO and MnFe2O4@ZnO–rGO nanocomposites through chemical facile hydrothermal procedure at low temperature of 180 °C for 3h.We reported the successfully synthesis of the MnFe2O4@ZnO nanocomposite via the co-precipitation method and was calcined at 200 °C for 3 h. Our synthesis of MnFe2O4@ZnO modified by the different weight percentages of GO and rGO.The as-synthesized samples were investigated by techniques XRD, FE-SEM, EDS, TEM,FT-IR,UV-DRS, PL, BET. TEM observations have displayed that MnFe2O4@ZnO nanoparticles were deposited on the graphene oxide and reduced graphene oxide surface. Magnetic studies demonstrated that the MnFe2O4@ZnO–GO and MnFe2O4@ZnO–rGO nanocomposites can be used as a magnetically separable photocatalyst.The photodegradation efficiency of the prepared materials was evaluated by the decomposition of Congo Red (CR) in 35 min of natural sunlight irradiation. Among the synthesized materials, the MnFe2O4@ZnO-GO photocatalyst showed maximum photocatalytic activity(99.54 % ).We also investigated the role of some scavengers in the degradation procedures to study the effect of active species. The studies from the radical scavengertests showed that active radicals like •O2 -, e, h+, and •OH were involved in the photodegradation of CR dye. The experimental results were applied to illustrate the proposed mechanism ability for improved photocatalysis. The Kinetics investigations have revealed that the degradation of CR by the prepared photocatalysts follows the pseudo-first-order kinetics and the rate constant attained for MnFe2O4@ZnO-GO (k = 78.10-3 min−1) was higher than of MnFe2O4@ZnO-rGO (k = 57.10−3 min−1).

In this research, a convenient, simple and rapid route for the preparation of Co3O4 nanoparticles using the calcination of Co(NO3)2∙6H2O at the presence of benzoic acid (1:1 weight ratio) is reported. Further, the as-prepared Co3O4 nanoparticles were characterized by X-ray powder diffraction (XRD) and transmission electron microscopy (TEM). XRD result confirmed the Co3O4 nanoparticles are pure phase and the average crystallite size for Co3O4 nanoparticles was found 77 nm. The TEM images reveal nanoparticles with size ranging from 50 to 100 nm, which is in conformity with the calculation of average crystallite sizes from XRD patterns. Furthermore, the prepared Co3O4 nanoparticles were investigated as an anode material for Li-ion batteries. Results showed that the Co3O4 nanoparticles exhibited excellent electrochemical performance and cycling stability, a capacity of 1127 mA h g-1 was obtained at 100 mAg-1 and the samples exhibited stable discharge behavior up to 130 cycles with high rate capability.

Fe3O4 magnetic structure was synthesized with co-precipitation method. Surface of magnetic core was modified with hydrophobic BMIM[PF6] ionic liquid. The samples became antibacterial by loading gold, copper and silver nanoparticles and denoted as Fe3O4/IL/X (X=Ag, Au, Cu). X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), thermal gravimetric analysis (TGA), Atomic absorption spectroscopy (AAS), Fourier transform infrared (FTIR) and vibration sample magnetometer (VSM) technics were applied for catalysts characterization, metal concentration analysis and morphology monitoring. Modified nanostructures were used for inactivation of Escherichia coli as the gram negative and Staphylococcus aureus as the gram positive of bacteria. Transmition electron micrscopy (TEM) images indicated that highest bacteria cell walls destruction is achieved when the surface of the magnetic nanostructure is coated with gold particles. Hydrogen bonds between cell wall and ionic liquid and gradual release of metals from Fe3O4/IL surface facilitate the metals arrive to outer layer of bacteria. Minimum inhibitory concentration (MIC) study approved the positive effect of ionic liquid.

Nanofibers are one of the most widely used materials in various industrial sectors. Among them Titanium Dioxide (TiO2) nanofibers are excelled, moreover they are environmentally friendly and have shown that they have diverse industrial applications. The physical structure of this fiber (diameter and surface characteristics) is a key effective factor on its behavior for corresponding applications. In this study, the effects of different factors influencing the diameter of TiO2 nanofibers were analyzed and quantified using two statistical analyses namely the Response Level Method (RSM) and the Composite Central Design (CCD) method. The preparation parameters of polymer synthesis including the electrical potential, the distance between electrodes tips, flow rate, and ambient humidity were studied. Results marked polymer concentration as the most important factor affecting the diameter of the nanofibers. However the diameter was almost independent from flow rate, and hence marked as the least effective factor. Furthermore, as humidity increased, the diameter of the fibers decreased significantly and surface roughness increased as demonstrated in the SEM and FESEM images. Since the relative humidity has intense impact on the structural properties of titanium dioxide nanofibers, humidity condition of synthesis space must be strictly controlled and kept below a threshold (38%).

Titanium dioxide nanowires have been prepared by the alkali hydrothermal treatment of TiO2 nanoparticles in presence of different hydroxides and characterized using transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive x-ray (EDX), N2 adsorption-desorption measurements, powder x-ray diffraction (XRD) and UV-Vis spectroscopy. Interestingly, only the strong bases (NaOH and KOH) formed mainly anatase titanium dioxide nanowires with the evident collapse of definitive (110) rutile XRD peak. The KOH-based titanium oxide nanowires exhibited comparatively low diameter (∼5 nm), high surface area (228.34 m2/g), and low band gap energy (2.90 eV), and showed the most remarkable photocatalytic degradation (98.87 %). However, the NH4OH-based titanium dioxides were nanoparticles having insignificantly modified morphology and least photocatalytic efficiency. The effect of operating variables on the degradation of aqueous methylene blue (MB) over the obtained alkali hydrothermal TiO2 was studied using response surface methodology, based on a bivariate central composite design (CCD) and optimized numerically.

Recently, attention to polymeric nanocomposites has gained a great extent as they present new opportunities to provide superior properties in microwave absorbing materials. In this study polystyrene (PS) nanocomposites containing various nano-fillers were successfully synthesized and employed as microwave absorbing materials. The mentioned materials are usually designed to solve protection against electromagnetic interference in wireless communication systems and high frequency circuit mechanisms. In this study the performance of three various polystyrene (PS) nanocomposites containing: semi-conductor zinc oxide, non-metallic conductive graphene oxide and magnetic Fe3O4 were compared. The fillers type was selected as variable parameter and its influence on the electromagnetic wave absorption and reflection loss (RL) amount was investigated. The scanning electron microscopy (SEM) was used in morphological and particle size study of the nanocomposites. The electromagnetic wave absorption properties of nanocomposites were studied and compared using a vector network analyzer (frequency range of 5-8 GHz). The results indicate that at the same preparation conditions the polystyrene/graphene oxide nanocomposites have higher absorption compared with others.

SiC nanocrystals are synthesized by sol-gel processing with tetraethoxysilane and green carbon sources (sugar, molasses, and stevia extract) as starting materials. The reactions of carbon precursors and silicon were investigated using density functional theory. To obtain the discrepancy between the energy levels of the interacting orbitals of precursors, molecules were optimized using B3LYP/6-31+G(d,p) method. XRD, FE-SEM, TG-DTA and FTIR analysis were implemented in order to compare the efficiency of different carbon sources. According to XRD experiments, SiC nanocrystals prepared by sugar and molasses had no contamination, while the sample prepared by stevia has impurity in the form of carbon and silica. TG-DTA results revealed that this difference is due to the fact that the carbon source in stevia did not react efficiently with silicon. Moreover, based on the DFT study and HOMO and LUMO analysis on the reactive energy of silicon and carbon precursors, it is revealed that sugar has the best reactivity among carbon sources for SiC formation.

A new nanomaterial based on folic acid functionalized dendritic fibrous nano-silica (FA-KCC-1-NH2) was synthesized and used as a recyclable solid acid and heterogeneous nanocatalyst towards efficient amidation of a variety of carboxylic acids with amines in toluene under reflux conditions. KCC-1 porous nanomaterials were produced utilizing a hydrothermal technique and in the next functionalized with folic acid moieties to yield KCC-1-NH-FA nanocatalyst. The structure of KCC-1, KCC-1-NH2 and KCC-1-NH-FA nanoparticles were investigated by FESEM, DLS, zeta potential and TEM, instrumental techniques. Also, the pore size of KCC-1-NH-FA nanoparticles were moreover investigated with BET where results revealed that the surface of this nanocomposite was expanded. The synthesized KCC-1-NH-FA nanoparticles showed effective catalytic activity in amidation of carboxylic acids with amines affording in high yields (76-89%) and short period of times. Moreover, other advantages of present method are easy workup, no need to use of chromatographic column and excellent recyclability of catalyst without significant loss in its catalytic activity which gives economic rewards.