Search

Ni 1-x Ag x O nanoparticles (NPs) with x = 0.00, 0.02, 0.04, 0.06, and 0.08) were fabricated using the composite hydroxide mediated (CHM) method. The effects of Ag doping on the structural, magnetic, and antimicrobial characteristics of NiO NPs have been reported. The stretching mode of the Ni–O molecules was identified at 443 cm−1 in the Fourier transform infrared spectra. The aggregation of nanoparticles with different sizes and shapes is seen under transmission and scanning electron microscopes. The blocking temperature (T B) peak in zero-field cooled (ZFC) magnetization curves display the magnetization from the core of NPs. This peak is absent for the samples with x = 0.00 and 0.02 , which show instead a small net magnetization from the antiferromagnetic core of these NPs. However, a T B peak was found for the samples with x = 0.04 , 0.06 and 0.08 , at 22, 72, and 65 K, respectively, which indicates that the magnetization is induced from the AFM core of NiO NPs for higher Ag doping. With an increasing concentration of Ag in the NiO NPs, the net magnetization did increase and a maximum was found for x = 0.04 at 300 K. For a higher doping concentration of 8 % Ag, a sharp decrease in magnetization was observed. Furthermore, the efficacy and synergistic effect of Ag doping had been analyzed for the effective improvement of the antibacterial properties of NiO NPs. Pure and Ag-doped NiO NPs were exploited to assess their anti-microbial activity against Enterobacter sp., E. coli, P. aeruginosa, and S. pyrogens. The study revealed that anti-bacterial or anti-biofouling properties were introduced as an additional attribute to NiO NPs by incorporation of Ag ions due to its inherent nature as an antimicrobial agent and enhanced its capability to sterilize microbial pathogens. [ABSTRACT FROM AUTHOR]

Magnetite nanoparticles (Fe3O4) were prepared by chemical coprecipitation method using ferric chloride (FeCl3) and heptahydrate ferrous sulfate (FeSO4·7H2O) salts employing sodium hydroxide (NaOH) as a precipitant. To determine the size, shape, and chemical makeup of the produced magnetite nanoparticles, the generated powders were examined by transmission electron microscope, scanning electron microscope, atomic force microscope, and X-ray diffractometer. It was found that the magnetite powder had made a face-centered cubic crystal structure and spherical-like particle form with particle diameters of about 30 nm. The magnetic properties of magnetite nanoparticles were evaluated using a vibrating sample magnetometer. The obtained superparamagnetic properties of the produced nanoparticles, with saturation magnetization and coercivity of 50.75 emu/g and 30.09 Oe, respectively, allow them for applications in drug delivery, MRI contrast agent, catalysis, degradation of antibiotics, antibacterial activity, removal of heavy metals and organic dyes, etc. [ABSTRACT FROM AUTHOR]

The present research is focused on synthesis of silver/gold nanoparticles using Caralluma sarkariae root extracts (CSR-AgNPs and CSR-AuNPs) used as capping/reducing agents and successfully carry out the pharmacological studies. The as-prepared CSR-AgNPs and CSR-AuNPs were systematically characterized using various analytical techniques. Moreover, the formation of CSR-AgNPs & CSR-AuNPs was confirmed by SPR values observed at 432 and 537 nm in UV–Visible spectroscopic. Morphological information of CSR-AgNPs & CSR-AuNPs were investigated using scanning electron microscope (SEM) and high-resolution transmission electron microscope (HR-TEM) analysis and as-synthesized nanomaterials were spherical in nature with mean size of 20 and 22 nm, respectively. The prepared nanoparticles clearly proven that the as-prepared nanoparticles exhibit high performance efficiencies in terms of in vitro antioxidant, anti-inflammatory, antibacterial and antifungal activities. The wound healing activity of as-fabricated CSR-AgNPs and CSR-AuNPs were carried out separately using three different methods such as in vitro scratch assay, MTT assay, and fluorescence staining methods. Furthermore, the fibroblast L929 cells were used for the wound healing activity of both nanoparticles and aqueous CSR extract in in vitro scratch assay. Moreover, the wide range of diseases could be treated by using the nanoparticles as-synthesized due to their outstanding pharmacological activities. [Display omitted] • Biosynthesis of AgNPs and AuNPs using Caralluma Sarkariae root extract. • Both AgNPs and AuNPs examined here has excellent pharmacological activities. • The formation of AgNPs and AuNPs were confirmed by different analytical techniques. • Compared to plant extract, both nanoparticles showed greater anticancer activity. [ABSTRACT FROM AUTHOR]

The reproducible synthesis of boron nitride (BN) nano-onions by lamp ablation is reported, exclusively from hexagonal BN precursor powder in vacuum, in a one-pot procedure that is free of toxic or harmful reagents, uncomplicated, potentially scalable and rapid. A high-resolution Scanning Electron Microscope image shows a "forest" of such nano-onions as they evolve between precursor flakes. A Transmission Electron Microscope image illustrates the range of nano-onion sizes and shapes. A coarse schematic of the proposed formation mechanism is also shown. [Display omitted] We report the generation of boron nitride nano-onions (BNNOs) from pure hexagonal-BN crystallite powder in vacuum, via a one-pot, non-toxic, catalyst-free, rapid and potentially scalable high-temperature lamp ablation procedure. An array of characterization procedures revealed nanoparticle (a) shapes and sizes, morphing from polyhedral for diameters of order 101 nm to quasi-spherical at diameters of order 102 nm, and (b) composition, with a 1:1 B:N ratio while also confirming the absence of contaminants. A formation mechanism is proposed whereby BNNOs evolve from the initial thermal exfoliation of the bulk precursor powder into nano-platelets. They fold and close into hollow nano-cages that are more stable thermodynamically. Reactor temperatures were measured to be ∼ 1500–1600 K for experiments yielding the largest amounts of BNNOs. A relatively narrow range of ∼ 1300–1800 K can be established for viable BNNO generation. Structural modeling sheds light on the relative stability of the nanostructures as a function of shape, size and number of layers. [ABSTRACT FROM AUTHOR]

ZnO and cadmium (Cd)-doped ZnO (Zn1-xCdxO) nanoparticles with various compositions (0.0 ≤ x ≤ 0.8) were synthesized by sol-gel method. Structural, morphological, and photocatalytic properties as well as blood compatibilities of Zn1-xCdxO nanoparticles were investigated. While X-ray diffraction (XRD) applying the Rietveld refinement method was used to characterize the structural properties, scanning electron microscope (SEM) and transmission electron microscope (TEM) were used to investigate the surface morphology. It was found that the nanoparticles up to x < 0.03 Cd concentration had single phase of ZnO hexagonal wurtzite structure. Above x ≥ 0.03 Cd concentration, two phases (ZnO and cadmium oxide (CdO)) were observed. SEM images with different magnifications revealed the dense, quasi-spherical, and agglomerated morphology of Zn1-xCdxO nanoparticles. The elemental compositions of Zn1-xCdxO nanoparticles have also been studied by EDX analysis. The photocatalytic activities and blood compatibilities of Zn1-xCdxO nanoparticles were studied by the photocatalytic degradation tests of crystal violet (CV) and hemolysis tests and respectively. In the photocatalytic activity tests, two samples Zn0.90Cd0.10O and Zn0.80Cd0.80O stood out with photodegradation percentages of 69.9% and 72.8%. Among the Cd-doped nanoparticles, the Zn0.40Cd0.60O sample showed the highest blood compatibility with the weakest photocatalytic performance (degradation percentage; 32.2%). Structural properties, photocatalytic performance, and hemolytic potential of Zn1-xCdxO nanoparticles were investigated and compared with those of pure ZnO nanoparticles. [ABSTRACT FROM AUTHOR]

Since the development of bacterial resistance towards antibiotics has the potential to limit the effectiveness of antibiotics in the treatment of infectious diseases, it is necessary to try different strategies to provide alternatives. In order to solve the problems, this work used silver nanoparticles‐loaded polydopamine‐modified montmorillonite (AgNP/PDA−Mt) to cope with the infection of the gram‐negative bacteria Escherichia. Coli and the gram‐positive bacteria Staphylococcus. aureus. Polydopamine‐modified montmorillonite (PDA−Mt) was used to reduce silver ions into silver nanoparticles through the hydroxyl groups of polydopamine. The chemical properties and morphology of AgNP/PDA−Mt were analyzed by X‐ray diffraction spectroscopy (XRD), fourier transform infrared spectroscopy (FT‐IR), transmission electron microscope (TEM), scanning electron microscope (SEM), etc. Also, its antimicrobial property has been investigated. The results showed that AgNP/PDA−Mt possessed significant sterilization at low doses. And the results had been shown its acceptable biocompatibility. [ABSTRACT FROM AUTHOR]

Niobium pentoxide (Nb2O5) is a promising heterogeneous acid catalyst because of its water‐tolerant acidity. However, the reactivity of Nb2O5 is limited to the surface of a bulk material; thus, its catalytic activity is generally lower than homogeneous catalysts. Nano‐sized Nb2O5 shows superior activity but has low stability and recoverability. We develop spiky‐shaped Nb2O5 composed of radially grown nanorods, which show high stability but low acidity. In this study, an Al‐doping method and the doping effect on the acidity and nanostructure of the spiky‐shaped Nb2O5 are demonstrated. Al of 1–6 mol% is doped in Nb2O5 while maintaining the spiky nanostructure using an Nb–Al composite oxalate as a precursor. Scanning transmission electron microscope analysis results show that the doped Al ions are homogeneously dispersed in the structure. Al doping increases the catalytic activity, where 4 mol% Al‐doped Nb2O5 shows the highest production rate of 2‐phenyl‐2‐phenylaminoacetonitrile in a Strecker reaction. From the acid analysis and Raman spectroscopy, it can be concluded that the Al doping is effective in adjusting acidity and in enhancement of catalytic activity due to creation of NbO4 and distorted NbO6. These are produced by defect formation and lattice distortion caused by differences in valence and ionic radius between Al and Nb. [ABSTRACT FROM AUTHOR]

In this study, zinc ferrite nanoparticles with a diameter of less than 50 nm were synthesized. Using XRD (X-ray Diffraction), Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM) the morphology and structure of this ferrite was investigated. The formation of spinel phase in Zn-Mn ferrite was shown by X-ray analysis. SEM photograph has shown spherical shape of nanoparticles and the dimensions of the samples were confirmed by Transmission Electron Microscope (TEM) at the nanoscale. Using the Debye-Scherrer formula, the size of Mn ferrite nanoparticle crystals was calculated to be about 13 nm. To check the properties related to the sensitivity of this ferrite, a fully insulated Plexiglass box was used and placed in it. By injecting 1 mL of liquid and vapor it, we will have 200 ppm concentration of each sample in this box. Then the injected vapored sample in this box is exposed to the ferrite. After this step, the conductivity of the ferrite in a closed circuit was changed. By changing the sample type, amount of this conductivity was varied. Five gases were tested in this project: ethanol, dimethyl formamid, carbon tetrachloride, acetonitrile and acetone. Among these samples the carbon tetrachloride had the best sensitivity performance. Finally, the sensor equation for carbon tetrachloride was extracted by applying different concentrations of it from 20 to 200 ppm. [ABSTRACT FROM AUTHOR]

This study aims at the characterisation of red and orange glass tesserae from the 4th-century Roman villa of Noheda (Spain). Due to the limited number of analyses available for such ancient materials, many questions remain unanswered about the production processes in the Roman period. Six samples were chosen for their hue variations, including two samples showing banded patterns of red and orange. Differences in copper speciation were investigated by X-ray absorption spectroscopy and compared with colour and compositional variations obtained by EPMA. The shapes and sizes of colouring crystals could be investigated using scanning and transmission electron microscope imaging. The brown-red colour is due to metallic copper nano-particles and corresponds to a low-copper and low-lead group usually described in the literature. The orange samples and bands are coloured by copper oxide C u 2 O nanoparticles with remaining Cu+ in the glass and have greater contents of Cu. Compositional analyses reveal that the same base glass is used in the red and orange bands with additions of Cu, Sn, Pb and probable Fe. Furthermore, based on our results and on the literature review, a high-copper low-lead group of glasses highlights the variability of compositions observed in cuprite colours. [ABSTRACT FROM AUTHOR]

Zinc oxide and zinc sulphide nanoparticles were produced using the sol-gel method. We employed nanoparticle identification methods for the examination of several factors. The precursor solutions are converted into an intermediate state that mimics gel during the sol-gel process, and then solidified. This technique provides fine control over the size, shape, and crystallinity of the resultant ZnO nanoparticles, hence modifying their electrochemical behaviour in the context of supercapacitor applications. An X-ray diffraction (XRD) examination revealed that the synthesized ZnO nanoparticles had a hexagonal character, while the ZnS nanoparticles had a cubic nature with diameters of around 22 nm and 36 nm, respectively. A transmission electron microscope (TEM) and a scanning electron microscope (SEM) are used to study the morphology and structural analysis. A particle size, surface area, production methods and testing settings are only a few of the variables that affect certain capacitances. In general, ZnO is recognized for displaying a certain capacitance that is frequently cited as being higher than ZnS. At a scan rate of 5 mV, the specific capacity of ZnO nanoparticles was found to be 33.2 F/g, whereas that of ZnS nanoparticles was found to be 6.5 F/g at a scan rate of 10 mV. One way to monitor pseudo capacitive behavior is by cyclic voltammetry. [ABSTRACT FROM AUTHOR]

Background: Nanotechnology is a fast developing science which has various applications in agriculture. Nanoparticles are broadly defined as the small particles with at least one-dimension size between 1 and 100 nm in diameter. Nanomaterials have the potential to penetrate the seed coat and enhance the ability of absorption and utilization of water, which stimulates enzymatic system and ultimately improves germination and seedling growth. The present study was undertaken to investigate the effects of nanoparticles and commercially used chemicals on breaking dormancy of Amorphophallus corms. Methods: Silver (Ag), zinc oxide (ZnO), titanium dioxide (TiO2 ), cerium oxide (CeO) and zero valent iron (ZVI) nanoparticles were synthesized successfully using chemical method and characterized for its size, shape and properties using Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), Particle Size Analyzer (PSA) and Raman spectroscopy. Freshly harvested corms of Amorphophallus were treated with different concentrations (50 and 100 mg kg-1) of these five nanoparticles and commercially used chemicals viz., thiourea (100 and 200 mg kg-1) and potassium nitrate (1000 and 2000 mg kg-1), with three different soaking periods (2, 4 and 6 h). Result: The analysed data indicated that corms treated with ZnO @ 100 mg kg-1 for six hours registered the minimum number of days (47.0 days) for sprout emergence. The maximum sprout length (23.50 cm), sprout diameter (6.35 cm), pseudo stem length (31.00 cm), pseudo stem girth (7.35 cm) and vigour index (1591.7) were recorded in TiO2 @ 50 mg kg-1 for two hours. [ABSTRACT FROM AUTHOR]

Composite materials are materials that are made of two or more materials that remain separate and differ on a macroscopic level while forming a single component so as to produce a composite material that has different mechanical properties and characteristics from the material it forms. Particle composite materials consist of particles held together by a matrix. In this study, an epoxy resin matrix was used with Polymesoda erosa clam shell nanopowder filler. Nano-sized fillers have many advantages over macro-sized ones. The nano-sized particles will have a high surface area, thereby increasing the mechanical strength of the material. The powdered nanoparticles produced will be analyzed using Fourier Transform Infrared (FTIR), Transmission Electron Microscope (TEM), and Scanning Electron Microscope (SEM). Based on the results of SEM and TEM, the nanopowder of clamshell has a size below 100 nm. The FTIR results of the powdered shellfish showed the presence of carbonate bonds C-O, C=O, and Ca-O. [ABSTRACT FROM AUTHOR]

Starch stain is a common stain on paper artifacts. This stain leads to deformation of the surface of the paper and promotes the growth of microbiological deterioration. This study aims to use nanoparticles with an α-amylase enzyme to improve its quality for removing this type of stain from the surface of paper artifacts. Accelerated heat aging was used on starch stain applied on the new paper samples. The α-amylase enzyme was prepared. Silver and gold nanoparticles were biosynthesized by local fungal isolation. The produced silver and gold nanoparticles were characterized by using different techniques of analysis (UV- Visible spectroscopy, Transmission Electron Microscope (TEM), and X-Ray diffraction (XRD) analysis). Different concentrations of Ag-NPs and Au-NPs were added to the α-amylase reaction mixture to enhance its activity for removing starch stains. Some analytical techniques were also used for the evaluation of the efficiency of α-amylase and nanoparticles for removing starch stains (Color measurement, Scanning Electron Microscope (SEM), and pH measurement). The results proved that Ag-NPs at 20 microliters increased the activity to about 160%, whereas Au-NPs enhanced the activity to about 140% at a concentration of 5μL. The results showed that α-amylase enzyme incorporated with Ag-NPs exhibited better results more than its use alone. The addition of Ag-NPs to α-amylase enzyme for the removal of starch stain reduced the total color differences, improved the surface morphology. [Display omitted] [ABSTRACT FROM AUTHOR]

In this work, a novel DHA-loaded nanoparticle with PLGA and chitosan (PCSDNP) was successfully prepared. The structure of PCSDNP and DHA-loaded PLGA nanoparticles was measured by transmission electron microscope, scanning electron microscope, and differential scanning calorimeter. The interaction strength between DHA, PLGA, and chitosan was evaluated through Fourier transform infrared spectroscopy. The curves of controlled DHA release and stabilities for different environmental factors of two NPs were evaluated. Importantly, two NPs were almost regularly spherical and the interactions were hydrogen bonds and electrostatic interactions between PLGA and chitosan. These NPs had a good encapsulation rate (80.45%) and high-water solubility than the free DHA molecule. In simulated gastrointestinal fluid, two NPs showed a controlled-release pattern. Overall, PCSDNP had better stability and controlled-release effect with the synergy between CS and PLGA under the conditions of pH (2– 7), ionic strength (0– 500 mM), storage time (0– 42 d), and temperature (30– 80 °C). [Display omitted] [ABSTRACT FROM AUTHOR]

The present work reports a simple approach for large-scale synthesis of hausmannite manganese oxide, Mn3O4 nanoparticles. The as-synthesized nanoparticles were subjected to different characterization techniques such as X-ray diffraction, FT-Raman, Fourier transform infrared spectroscopy, scanning electron microscope with energy-dispersive X-ray spectroscopy, transmission electron microscope and vibrating sample magnetometer analysis. The electrical properties are examined with current–voltage characteristics. Crystal phase and hausmannite structure were confirmed by X-ray diffraction and Raman analysis. The resulting nanoparticles exhibited uniform size distribution and good stability as confirmed from electron microscopy studies. The synthesized nano-Mn3O4 is further evaluated for its potential in dye degradation and photocatalytic applications. The coexistence of Mn3O4 and H2O2 plays an important role on efficient decomposition of methylene blue dye from water. [ABSTRACT FROM AUTHOR]

The present study focuses on the novel synthesis of cerium oxide (CeO 2) nanoparticles from cerium nitrate hexahydrate by using Azadirachta indica (neem) leaf extract. The parameters associated with the green synthesis process were optimized utilizing the response surface methodology (RSM) paired with the genetic algorithm (GA) to produce a higher yield rate. The experiment run order for the CeO 2 green synthesis is then generated using the central composite design in RSM. The regression equation was used as an optimization function, and the optimal values were identified through GA. Using optimized input process parameters, 0.3 g/10 mL of precursor concentration and 5 mL of Azadirachta indica leaf extract centrifuged for 20 min in the green synthesis process resulted in a maximum yield of 15.49 % CeO 2 nanoparticles. The synthesized CeO 2 nanoparticles are characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), particle size distribution, and zeta potential analyses, which are used to ensure their presence in the green synthesis process. Subsequently, the green synthesized CeO 2 nanoparticles are dosed as an additive to the cotton seed biodiesel (CSB) at different proportions of 25, 50, and 75 ppm, respectively. The prepared biofuel's physico-chemical properties were measured as per ASTM standards and are closer to the diesel fuel. As a result, it was noted that optimizing the green synthesis process parameters gives a maximum rate of CeO 2 yield. It is possible to efficiently use the CSB with CeO 2 nanoparticles as a suitable replacement for diesel fuel. [Display omitted] • Novel leaf extract for the sustainable synthesis of CeO 2 nanoparticles. • Green synthetic CeO 2 yield forecasted by RSM's central composite design. • A hybrid RSM-genetic algorithm approach to process parameters optimization. • A characterization study was done on environmentally friendly CeO 2 nanoparticles. [ABSTRACT FROM AUTHOR]

Supported Pt nanoparticles are used extensively in chemical processes, including for fuel cells, fuels, pollution control and hydrogenation reactions. Atomic-level deactivation mechanisms play a critical role in the loss of performance. In this original research paper, we introduce real-time in-situ visualization and quantitative analysis of dynamic atom-by-atom sintering and stability of model Pt nanoparticles on a carbon support, under controlled chemical reaction conditions of temperature and continuously flowing gas. We use a novel environmental scanning transmission electron microscope with single-atom resolution, to understand the mechanisms. Our results track the areal density of dynamic single atoms on the support between nanoparticles and attached to them; both as migrating species in performance degradation and as potential new independent active species. We demonstrate that the decay of smaller nanoparticles is initiated by a local lack of single atoms; while a post decay increase in single-atom density suggests anchoring sites on the substrate before aggregation to larger particles. The analyses reveal a relationship between the density and mobility of single atoms, particle sizes and their nature in the immediate neighbourhood. The results are combined with practical catalysts important in technological processes. The findings illustrate the complex nature of sintering and deactivation. They are used to generate new fundamental insights into nanoparticle sintering dynamics at the single-atom level, important in the development of efficient supported nanoparticle systems for improved chemical processes and novel singleatom catalysis. This article is part of a discussion meeting issue 'Dynamic in situ microscopy relating structure and function'. [ABSTRACT FROM AUTHOR]

Green synthesized metallic nanoparticles are continually receiving attention as antimicrobial agents and catalyst for degradation of a host of organic compounds. In this study, silver nanoparticles were synthesized using Aspilia pluriseta extracts and evaluated for their antimicrobial and photocatalytic activity. Using a UV–Vis spectrophotometer, the surface plasmon resonance observed at 427 nm indicated the materialization of silver nanoparticles. Probable vibrational stretches that are characteristic of silver nanoparticles such as –OH stretching vibrations and –CH2 vibrational stretch, were identified using an FT-IR spectrophotometer. In order to understand the morphology and composition of the synthesized nanoparticles, they were studied further using scanning electron microscope (SEM), dynamic light scattering analyzer (DLS), transmission electron microscope (TEM) and X-ray diffractometer (XRD) hence revealing formation of crystalline, spherically shaped silver nanoparticles. The synthesized silver nanoparticles (AgNPs), exhibited broad-spectrum activity which was concentration dependent against; two-gram positive bacteria (Bacillus subtilis and Staphylococcus aureus), two-gram negative bacteria (Escherichia coli and Pseudomonas aeruginosa) and the fungal (Candida albicans). Effectiveness of the nanomaterials in photocatalytic degradation was based on irradiation time. Decolorization and degradation of the dye took less than 30 min. [ABSTRACT FROM AUTHOR]

A well-organized, simplistic, and green route of chitin-glucan based zinc oxide nanoparticles (ChGC@ZnONPs) was synthesized using reducing and capping agent both in one as chitin-glucan complex (ChGC). Herein we report the bio-synthesis of Cur-ChGC@ZnONPs by the conjugation of curcumin (Cur) with ChGC@ZnONPs for the improvement of antioxidant and antibacterial activity. The synthesized nanoparticles were characterized by the UV–Visible (UV–Vis), particle size analyser, scanning electron microscope (SEM) with Energy-dispersive X-ray spectroscopy (EDX), Transmission electron microscope (TEM), X-ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FT-IR). Structure analysis, shape and crystalline size of nanomaterials were confirmed by scanning electron microscopy (SEM) and Transmission Electron Microscopy (TEM). The particle size analyser showed the particle size of nanomaterials and stability. Crystalline nature of both ChGC@ZnONPs and Cur-ChGC@ZnONPs were confirmed by the XRD spectra and FT-IR spectrum was used to examine the functional groups of nanomaterials. The antioxidant potential of conjugated nanomaterials were estimated using a DPPH free radical scavenging assay and ABTS+⁎ assay. This analysis showed that after loading of Cur, antioxidant activity increases. The antibacterial assessment of conjugated nanomaterials were tested by different microorganisms and showed excellent antibacterial activity. [ABSTRACT FROM AUTHOR]

Nanozymes exhibit excellent enzyme‐like activities but lack specificity. Here, molecularly imprinted polymers (MIPs) based on polypyrrole (PPy) and using methylene blue (MB) as template were grown on Fe3O4 nanozymes to enhance the catalytic selectivity. The obtained composite Fe3O4@PPy MIPs were characterized using a scanning electron microscope, transmission electron microscope, powder X‐ray diffractometer, and vibrating sample magnetometer. The PPy‐encapsulated Fe3O4 nanozymes retained their catalytic ability and almost completely removed MB within 30 min in the presence of sodium persulfate. In comparison with bare Fe3O4 nanozymes, the Fe3O4@PPy MIPs showed superior catalytic selectivity for MB. The apparent rate constants (kapp) for MB, rhodamine B, and methyl orange were 0.073, 0.035, and 0.012 min−1, respectively. Even after five recycling steps, the obtained Fe3O4@PPy MIPs could degrade more than 80% of MB. [ABSTRACT FROM AUTHOR]

Layered metal/dielectric hyperbolic metamaterials (HMMs) support a wide landscape of plasmon polariton excitations. In addition to surface plasmon polaritons, coupled Bloch‐like gap‐plasmon polaritons with high modal confinement inside the multilayer are supported. Photons can excite only a subset of these polaritonic modes, typically with a limited energy and momentum range in respect to the wide set of high‐K modes supported by hyperbolic dispersion media, and coupling with gratings or local excitation is necessary. Strikingly, electron energy loss spectroscopy (EELS) in a scanning transmission electron microscope allows nm‐scale local excitation and mapping of the spatial field distribution of all the modes supported by a photonic or plasmonic structure, both bright and dark, and also all other inelastic interactions of the beam, including phonons and interband transitions. Herein, experimental evidence of the spatial distribution of plasmon polaritons in multilayered type II HMM nanostructures is acquired with an aloof electron beam adjacent to structures of current interest. HMM pillars are useful for their separation and adjustability of optical scattering and absorption, while HMM slot cavities can be used as waveguides with high field confinement. The nature of the modes is confirmed with corresponding simulations of EEL and optical spectra and near‐field intensities. [ABSTRACT FROM AUTHOR]

Green synthesizes of nanoparticles made a curiosity in the field of nanobiotechnology and they have a wide range of application. In this investigation, the leaf extract of Andrographis serpyllifolia was used to synthesis silver nanoparticles as a greener approach. These green silver nanoparticles characterized by UV-Spectrophotometer, Fourier transform-infrared spectroscopy (FTIR), X-ray diffraction (XRD), Scanning Electron Microscope (SEM), Energy-dispersive X-ray spectroscopy (EDX), Transmission Electron Microscope (TEM), Zeta potential and particle size analysis. The silver nanoparticles were of spherical in nature with a minimum of 3.4 nm to a maximum of 71.6 nm with the average size of 24.1 nm. The larvicidal study showed that the AgNPs were highly active against the Culex quinquefasciatus larvae and the LC50 value observed was 68.889 µg/ml and LC90 value observed was 392.117. In addition, the antimicrobial study revealed that the A. serpyllifolia intervened AgNPs have shown prominent activity against the clinical pathogens viz., Staphylococcus aureus, Streptococcus pneumoniae, Pseudomonas fluorescens, and Escherichia coli. The maximum zone of inhibition observed against the S. pneumoniae was 21.33 ± 0.88 mm (75 µg/ml). Whereas, the lowest was observed against the S. aureus 14.66 ± 0.57 mm (25 µg/ml). The A. serpyllifolia mediated AgNPs demonstrated prominent bioactivity and used to control the emerging mosquito population and pathogenic microorganisms. [ABSTRACT FROM AUTHOR]

Ceria nanoparticles (CeO2 NPs) are generally considered in various functional applications, such as catalysts in fuel cells, sensors, and antioxidant and oxidase-like enzymes in the biological environment. The CeO2 NPs were synthesized using the E. globulus leaf extract-mediated hydrothermal technique. The synthesized NPs were characterized by various analytical instruments including powder X-ray diffractometer (PXRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and dynamic light scattering (DLS) analysis. The XRD results showed an average NPs sizes of 13.7 nm. Cytotoxic study results showed an IC50 value of 45.5 µg/L for A549 and 58.2 µg/L for HCT 116, indicating that CeO2 NPs are more toxic to A549 compared to HCT116 cell lines. The generation of ROS was responsible for its cytotoxic activity against cancer cell lines. Specific surface area (40.96 m2/g) and pore diameter (7.8 nm) were measured using Brunauer-Emmett-Teller (BET) nitrogen adsorption-desorption isotherms. CeO2 NPs with a high surface area were used as photocatalyst in degrading sunset yellow (SY) dye under UV-irradiation and 97.3% of the dye was degraded within 90 min. These results suggest that the synthesized CeO2 NPs could be used as a good photocatalyst as well as a cytotoxic agent against human cancer cell lines. [ABSTRACT FROM AUTHOR]

The influence of different calcination temperatures on the molecular structure, optical, morphological and antimicrobial activity were investigated for Zinc Oxide nanoparticles (ZnO NPs) synthesized using green sol-gel method. The prepared ZnO NPs are calcined at 70 °C, 300 °C, 400 °C and 800 °C. The effect of different calcinations temperature on the characterization of the prepared samples were studied using X-ray Diffraction (XRD), High Resolution Transmission Electron Microscope (HRTEM), High Resolution Scanning Electron Microscope (HRSEM), Fourier Transform Infrared (FT-IR), and Ultraviolet–Visible Spectroscopy (UV–Vis). In addition, the potential antimicrobial activity of ZnO NPs were investigated against four different pathogenic bacterial strains: two strain of gram negative bacteria (Pseudomonas Aeruginosa and Klebsiella Pneumonia) and two strain of gram positive bacteria (Bacillus subtilis and Staphylococcus Aureus). The results showed that XRD, UV–Visible and FT-IR confirmed the presence of ZnO nanoparticles. HRTEM and HRSEM reveal that as the temperature increase the size of prepared sample increased and the agglomeration increases. The best size of rod shape ZnO NPs found at 300 and 400 °C. Zinc oxide NPs prepared at 300 °C calcination temperature have the superior antibacterial effect on the gram positive and gram-negative pathogenic bacteria. Image 10946 • Synthesized ZnO NPs by the Sol-Gel method with different calcination temperatures. • As the temperature increased both the size and agglomeration increases. • HRSEM and HRTEM showed the best size of rod shape ZnO NPs found at 300 and 400 °C. • ZnO NPs at 300 °C have the superior antibacterial effect on pathogenic bacteria. [ABSTRACT FROM AUTHOR]

In this study, the preparation and consolidation of nanocrystalline LaB 6 powders originating from powder blends of La 2 O 3 , B 2 O 3 and Mg were reported. A consecutive route of mechanochemical synthesis (MCS) and purification was utilized for the achievement of nano-sized LaB 6 powders. As-synthesized powders were leached out from intermediate reaction products or impurities. Then, a sequential step of cold pressing (uniaxial pressure at 800 MPa) and pressureless sintering (at 1700 °C for 5 h under Ar gas flow) were utilized for the consolidation of the purified LaB 6 powders. The type of mill (vibratory and planetary high-energy ball mills) was employed as a MCS parameter to reveal its effect on the physical, microstructural and mechanical properties of the LaB 6 powders, and their bulk structures. Compositional, physical and microstructural properties of the products after powder processing were determined via X-ray diffractometer (XRD), particle size analyzer (PSA), differential scanning calorimeter (DSC), stereomicroscope (SM), scanning electron microscope (SEM), transmission electron microscope (TEM), energy dispersive spectrometer (EDS) coupled with both SEM and TEM, and vibrating sample magnetometer (VSM). The bulk properties of the LaB 6 consolidated from nanocrystalline powders with a minimum 99.99% purity, and ∼62 nm (for vibratory ball mill) or ∼74 nm (for planetary ball mill) average particle size were compared according to various properties. LaB 6 powders were synthesized in planetary mill at an approximately six times longer duration than that of in vibratory mill. According to the results, density, surface area and mean particle size values of the vibratory ball-milled samples (containing paramagnetic powders) are better than those of planetary ball-milled (containing diamagnetic powders) ones. However, mechanical properties such as hardness, surface roughness, wear rate, friction coefficient, and also electrical conductivity were improved in the planetary ball-milled LaB 6 bulks. [ABSTRACT FROM AUTHOR]

In this study, Copper-Polyaniline nanocomposite (Cu-PAni) has been synthesized by gamma radiolysis as a novel method and was confirmed by different analytical techniques such as Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), X-ray powder diffraction (XRD). The copper nanoparticle completely covered by a layer of polyaniline with different thickness. The particle mean size was determined from XRD by using the Debye-Scherrer's formula and the particle size was found to be 21 nm. The thermal conductivity of the nanofluid has been measured at different nanofluids volume fractions of 0.2%, 0.4%, 0.6%, 0.8% and 1.0%. The effect of nanofluid temperature on the nanofluid properties is measured in the range from 10 °C to 90 °C. The thermal conductivity ratio of the Copper-Polyaniline nanocomposites water nanofluid increases 107% at nanofluid temperature of 10 °C and 159% at 90 °C for a volume fraction of 1.0%. The Cu-PAni nanocomposite is a potential material for thermal conductivity enhancement of water based nanofluid. [ABSTRACT FROM AUTHOR]

In this study, Ru, Pt, Pd-based catalysts supported on Co 3 O 4 with microwave irradiation-polyol method is used for the hydrogen generation from NaBH 4 hydrolysis. Surface morphology and structural properties of the catalysts were studied by using X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS) and inductivity coupled plasma-mass spectrometer (ICP/MS). In addition to, an on-demand hydrogen generation system, which can produce hydrogen from NaBH 4 solution and in order to determine the activity of the prepared catalysts, is designed by our group. The effects of solution temperature, amount of catalyst and the initial concentrations of NaBH 4 /NaOH on the hydrogen generation rate are investigated. The highest hydrogen generation rate at 25 οC is obtained from Ru–Co 3 O 4 catalyst with 6514 ml/g cat.min. In addition, the highest hydrogen generation rate from hydrolysis of NaBH 4 with Pt–Co 3 O 4 catalyst is achieved at 55 οC as 23916 ml/g cat.min. The Ea values were calculated as 28.26 kj mol−1, 43.52 kj mol−1 and 65.82 kj mol−1 for Ru–Co 3 O 4 , Pt–Co 3 O 4 and Pd–Co 3 O 4 , respectively. Furthermore, it is observed that the increase in solution temperature had a very positive effect on the hydrogen generation rate of Pd based catalyst. • Ru, Pt and Pd nanoparticles supported on Co 3 O 4 by microwave irradiation method. • The activities of these catalysts were tested for hydrogen generation rate (HGR). • Solution temperature, catalyst amount and initial concentrations were investigated. • Ru–Co 3 O 4 catalyst showed the highest HGR at 25 οC as 6514 ml/g cat.min. • Temperature and NaOH concentration positively affect HGR of Pd–Co 3 O 4 catalyst. [ABSTRACT FROM AUTHOR]

The study compared the antibacterial activity of synthesized ZnO nanoparticles (NPs) from fresh leaf and fresh stem bark aqueous extracts of Carica papaya against five selected microbes: Staphylococcus aureus, (Gram positive (+ve)), Escherichia coli (Gram negative (-ve)), Acinetobacter baumanni (Gram-ve), Exiguobacterium aquaticum (Gram+ve), and Klebsielia pneumonia (Gram +ve). The morphological features of the biosynthesized ZnO NPs were analyzed using transmission electron microscope (TEM) and scanning electron microscope (SEM); the Fourier-transform infrared spectrometer (FTIR) technique was used to observe the surface functional groups. The experimental results indicated that ZnO NPs were successfully synthesized using modified hydrothermal technique, which showed agglomerated flake-like or petal-like shapes with the organic extract surrounding the formed particles. The average particle size of the synthesized ZnO nanoparticles determined by SEM ranged between 54-97 nm with the width and length of the petal-like structures been 30 nm and 62 nm respectively. The average ZnO NPs from fresh stem bark extract of Carica papaya with higher concentrations (100-1000 ppm) demonstrated a higher antibacterial activity than the fresh leaf extracts. On the other hand, ZnO NPs from fresh leaf extracts of lower concentrations (25-50 ppm) rather showed a suitable result than the fresh stem bark. In general, ZnO NPs showed a positive antibacterial result towards the selected microbes. This shows that, the synthesized ZnO NP can be a substitute to chemical methods. [ABSTRACT FROM AUTHOR]

Abstract Metallic nanoparticles such as gold, zinc, copper possess anti-microbial activity. These nanoparticles have a small size which provides a large surface area for the interaction with microbes and there are various mechanisms through which copper nanoparticles (CuNPs) act. The demand of these nanoparticles are increasing in the textile industry as they decrease the catalytic degradation property of various dyes as well as being helpful in the treatment of various topical infections. Our aim is to formulate the copper nanoparticle which is capped with Tinospora cardifolia and incorporate these nanoparticles on fabric and to study the anti-microbial activity of these nanoparticles formulated along with their study on the fabric. Formulated nanoparticles were tested for various characterizations such as SEM (Scanning Electron Microscope), TEM (Transmission Electron Microscope) for the microscopical study. The interaction of excipients with the drug was studied using FTIR, XRD, and Raman and the anti-microbial study was studied to determine the activity of the nanoparticles on gram-positive and gram-negative bacteria. Least particle size of 63.3 nm was used as optimized formulation (CuNPs-5) and further used for testing. Laundry durability, ZOI study and %efficacy of copper nanoparticles along with nanoparticle-coated fabric was tested and it was found that fabric was more efficacious for gram-positive bacteria as ZOI for gram positive and gram negative was 21.99 mm and 11 mm. The %efficacy of copper nanoparticle-coated fabric was 101% and 74% at the highest concentration for gram positive and gram negative bacteria respectively. Graphical abstract Unlabelled Image Highlights • Green synthesis of copper nanoparticles with the help of leaves extract of Tinosporia cardifolia. • Various characterization studies like particle size, zeta potential SEM, TEM ATR-FTIR, etc. were performed. • Anti-microbial study shows good results nano-coated fabric was valuable on gram +ve bacteria rather than gram -ve bacteria. • Laundry durability test for nano-coated fabric was 65% in case of gram-positive bacteria and 50% in case of gram-negative bacteria. [ABSTRACT FROM AUTHOR]

Graphical abstract Temperature dependence of dielectric constant. Highlights • The PCT nanoparticles were prepared by sol-gel & microwave heating method. • The frequency and temperature dependence of electrical properties are studied. • Nyquist plots are drawn to evaluate grain and grain boundary behaviour. • The ferroelectric transition was noticed at 683 K in the ε′ versus temperature plot. • The P-E loops were discussed as a function of temperature. Abstract The lead cobalt titanate nanoparticles were synthesized via the sol-gel technique followed by microwave heating at 750 °C for 45 min. The X-ray diffraction study revealed the formation of tetragonal PbCoTiO 3 phases. The average crystallite size was found to be 26 nm. The surface morphology was examined using field emission scanning and transmission electron microscopes. The dielectric properties such as dielectric constant (ε′), dielectric loss (ε″), ac-conductivity (σ ac), real (M′) and imaginary part (M″) of dielectric modulus were investigated as a function of temperature and frequency. The impedance analysis was carried out using Cole-Cole plots to elucidate the electrical conduction mechanism. The ferroelectric behavior of PCT was described by polarization versus input electric field (P-E) loop as a function of temperature. [ABSTRACT FROM AUTHOR]

A prospective novel technique has been developed for green synthesis of iridium nanoparticles of rod shapes for the first time with simultaneous formation of keto-derivative oxidation product with a yield of 98.3 %. This takes place by reduction of hexacholoroiridate (IV) by using sustainable pectin as a powerful reducing agent biomacromolecule in acidic media. The formation of nanoparticles (IrNPS) was identified by Fourier transform infrared (FTIR), Transmission electron microscope (TEM), X-ray diffraction (XRD), and Scanning electron microscope (SEM) investigations. The TEM morphology showed that the iridium nanoparticles were of crystalline rod shapes on contrary to the spherical shapes reported on all synthesized IrNPS earlier. The rates of nanoparticles growth were followed kinetically using a conventional spectrophotometer. The kinetic measurements revealed a unity order reaction in [IrCl 6 ]2− as oxidant and fractional first-order in [PEC] as a reducing agent, respectively. A decrease in the reaction rates was noticed with increasing the acid concentration. Kinetic evidence reveals the creation of intermediate complex as transient species prior to the slow step. Such complex formation may be facilitated by the participation of one chloride ligand from [IrCl 6 ]2− oxidant forming a bridge between the oxidant and reductant in such formed intermediate complex. Plausible reaction mechanisms for electron transfer pathway routes consistent with the kinetics observations were discussed. • Novel methodology for synthesis of nanoparticles using carbohydrate polymers • Green synthesis of iridium (0) nanoparticles of rod shapes by reduction of [IrCl6]2- by pectin • Identification of nanoparticles by FTIR and TEM techniques • Determination of the nanoparticles growth rates and nature of electron-transfer pathway routes • A plausible reaction mechanism for nanoparticles formation has been suggested and discussed. [ABSTRACT FROM AUTHOR]

Silver nanoparticles (AgNPs) were synthesized via green route with the aid of Pithecellobium dulce pod mesocarp aqueous extract. The appearance of the yellow color with surface plasmon resonance band at ca. 400–450 nm in UV–visible spectroscopy reveals the formation of AgNPs. The morphology of AgNPs strongly depends on the cetyltrimethylammonium bromide (CTAB). Transmission electron microscope (TEM) and scanning electron microscope (SEM) were used to determine the size, shape and the size distribution of AgNPs. To overcome the serious problems related to environment like discharge of hazardous dyes to water bodies, AgNPs have been found to be very important catalyst for the degradation of methyl orange (MO) and eosin yellow (EY) in presence of NaBH 4 . The pseudo-first order rate constant, activation energy, turnover frequency were found to be 2.2 × 10 −3 s −1 , 49.7 kJ mol −1 , 1.2 × 10 −3 s −1 and 1.4 × 10 −3 s −1 , 55.1 kJ mol −1 , 0.8 × 10 −3 s −1 , respectively, for methyl orange and eosin yellow degradation catalyzed by AgNPs. [ABSTRACT FROM AUTHOR]

Hexagonal Bi 2 Te 3 nanosheets with uniform morphology were facilely synthesized through a hydrothermal method at 180 °C. X ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and selected area electron diffraction (SAED) were employed to characterize the Bi 2 Te 3 nanosheets. The results clearly indicate that uniform Bi 2 Te 3 nanosheets with a side length of 300–400 nm were obtained. Bi 2 Te 3 nanosheet/ZnO nanoparticle (Bi 2 Te 3 NS/ZnO NP) composite photoanodes were fabricated with Bi 2 Te 3 NS concentration in the range of 0–0.25 at.%. The effect of Bi 2 Te 3 NS contents in composite photoanode on the performance of dye-sensitized solar cells (DSSCs) was systematically investigated. The photocurrent density-voltage ( J-V ) characteristics indicate that the DSSCs with Bi 2 Te 3 NS/ZnO NP composite photoanode exhibit significantly improved photovoltaic performance. Typically, the highest energy conversion efficiency of 4.10% which is increased by 46.95% compared with that of the bare ZnO can be achieved in the DSSC with 0.15 at.% Bi 2 Te 3 NS embedding. The EIS results further confirm that a moderate amount of Bi 2 Te 3 NS in photoanode could not only improve the electrons transport and suppress the charge recombination rate, but also enhance the electron collection efficiency. Furthermore, the excellent thermoelectric performance of Bi 2 Te 3 NS in the photoanode could greatly increase the electron density and lower the temperature of the DSSCs effectively. All these results suggest that the Bi 2 Te 3 NS/ZnO NP composite photoanode could highly enhance the performance of the DSSCs. [ABSTRACT FROM AUTHOR]

In the present study, this report discusses the preparation and photocatalytic properties of pure, Ag and Zn doped and Ag-Zn codoped TiO nanoparticles by sol-gel method. The powder X-ray diffraction study showed that crystallite size of doped and codoped TiO nanoparticles was decreased compared with pure TiO. The decreased particles size was confirmed by high resolution transmission electron microscope and the particle size was in the range of 7-19 nm. The influence of codopant on the morphology of Ag-Zn codoped TiO was clearly observed in the field electron scanning electron microscope. From the UV-Vis diffuse reflectance spectrum, it was observed that the doping and codoping of Ag and Zn reduce the energy gap of TiO. The reduced emission intensity of doped and codoped TiO in the photoluminescence spectrum suggests that the Ag and Zn lower the recombination of electron-hole pairs. The increase of Zn dopant level (0.2, 0.4 and 0.6 mol%) at 1 mol% of Ag in the codoped TiO further reduces the emission intensity. The 0.6 mol% of Zn at 1 mol% of Ag in the codoped TiO shows higher photocatalytic degradation ability against Reactive Yellow 145 under visible light compared with all other nanoparticles. [ABSTRACT FROM AUTHOR]

Zn(II) and Cd(II) metal complexes of 1-cyano-1-carboethoxyethylene-2,2-dithiolato–κ S , S ’–bis(N,N-dimethylthiourea–κ S ) have been synthesized and characterized with analytical and spectroscopic techniques. The complexes were thermolysed in hexadecylamine at 200 °C to prepare ZnS and CdS nanoparticles. The nanoparticles were characterized with scanning electron microscope (SEM), transmission electron microscope (TEM), and powder X-ray diffraction (p-XRD). TEM images showed spherically shaped nanoparticles, whose sizes are in the range 4.33–7.21 nm for ZnS and 4.95–7.7 nm CdS respectively and XRD confirmed cubic crystalline phases for the nanoparticles. The optical band gap energy evaluated from the absorption spectra are 2.88 eV (430 nm) and 2.81 eV (440 nm) for the ZnS and CdS nanoparticles respectively. The as-prepared metal sulfide nanoparticles were further incorporated into polyvinyl alcohol (PVA) to give ZnS/PVA and CdS/PVA composites. The polymer nanocomposites were studied to investigate their morphology and thermal properties relative to the pure PVA. XRD diffractions indicated that the crystalline phases of the nanoparticles and the sizes in PVA matrices remained unaltered. Infra-red spectra studies revealed interactions between the PVA and the metal sulfide nanoparticles and TGA studies show that the ZnS/PVA and CdS/PVA nanocomposites exhibit better thermal stability than the pure PVA. [ABSTRACT FROM AUTHOR]

[Display omitted] • CuO nanoparticles are successfully synthesized using green approach. • The energy band-gap was calculated to be 1.92 (papaya peel extract), and 1.22 eV (banana peel extract), respectively. • The degradation of MB is facilitated using CuO NPs under visible light. • Pseudo-first-order kinetics describes the degradation reaction satisfactorily. Copper Oxide (CuO) nanoparticles were synthesized through a green approach using the papaya and banana peel reducing as well as a stabilizing agents and copper (II) nitrate trihydrate salt as a precursor. The sample was characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), Scanning electron microscope (SEM), Transmission electron microscope (TEM), and UV–visible diffuse reflectance spectroscopy (DRS). The characterization results revealed about the CuO NPs structure, shape, energy gap, and functional group variations. The energy band-gap was calculated to be 1.92 (papaya peel extract), and 1.22 eV (banana peel extract), respectively. Under visible light irradiation, the photocatalytic activity of CuO NPs was investigated by degrading Methylene blue (MB) dye. It depicts that synthesized CuO NPs have a great potential for application as a photocatalyst to degrade textile colours in wastewater treatment in a short period. Moreover, the pseudo-first-order reaction rate constants were found to be 0.00359 min−1 (papaya peel extract) and 0.00335 min−1 (banana peel extract), respectively. [ABSTRACT FROM AUTHOR]

[Display omitted] • Non noble Copper oxide (CuO) NPs is synthesized with controlled size by quercetin mediated hydrothermal method. • The material is applied as heterogeneous catalyst for 'Click' Synthesis of 1, 2, 3-Trizoles. • The use of hazardous organic azides were avoided. • Quick formation of product was observed with excellent yields under mild reaction conditions. • The catalyst is recyclable, reusable and environmental friendly. 'Quercetin' a simplest flavanoid possessing five hydroxyl groups, is employed as a capping agent in CuO nanoparticles preparation with the help of hydrothermal autoclave. The CuO nanoparticles acted as an efficient and cost effective catalyst for 'click' synthesis of 1,4-disubstituted 1,2,3-triazoles. The physical and chemical properties of the prepared catalyst were characterized by various techniques such as, Fourier-transform infra red (FTIR), Simultaneous thermal analysis (STA or TG-DTA), Powder X-ray diffraction (P-XRD), Scanning electron microscope (SEM), Transmission electron microscope (HR-TEM) analysis and surface area analyzer BET (Brunauer-Emmett-Teller). The CuO nanoparticles prepared with quercetin were found to possess smaller size. The catalytic reaction was carried out under mild conditions and the yield of the products was reasonable. Even up to 6 catalytic cycles the CuO nanoparticles could give considerable yield of triazoles products. [ABSTRACT FROM AUTHOR]

• Fe, Co, and Ni doped MnO x was grown on NG. • Doped catalysts show better ORR activity than the undoped one. • Doping can tune the Mn valence. • Enhanced activity for doped MnO x owing to increase in Mn valence on doping. We report the electrochemical activity of transition metal ion (Fe, Co and Ni) doped MnO x @ N -graphene (MnO x @NG) hybrid catalysts towards oxygen reduction reaction (ORR). The doped catalysts displayed significantly enhanced electrochemical performance than the undoped one. The Fe doped MnO x @NG exhibited highest positive shift in onset potential (0.93 V vs. RHE), highest electron transfer number (n) (3.87) and lowest peroxide yield (6.35 %) in 0.1 M KOH solution. The Co doped catalyst showed highest current density, which is comparable to that of benchmark 20 wt% Pt/C. The XRD analysis showed that the catalyst samples are poorly crystalline and the doping of either Fe or Co or Ni cation induces formation of Mn 2 O 3 , whereas the undoped catalyst consists of both Mn 2 O 3 and MnOOH. The STEM (scanning transmission electron microscope) micrographs revealed that in all the samples the MnO x nanostructures are well dispersed on NG and the elemental mapping of the doped catalysts showed uniform distribution of dopants. The X-ray photoelectron spectroscopy (XPS) studies revealed that doping of either cation results an increase in the average Mn valency of the host MnO x. The change in crystal structure and corresponding ORR activity has also been investigated with increase in dopant amount for Fe doped samples. [ABSTRACT FROM AUTHOR]

Reduced graphene oxide-supported tungsten carbide composite (WC/RGO) was prepared by program-controlled reduction-carburization technique. Scanning electron microscope (SEM) and transmission electron microscope (TEM) show that WC nanoparticles with a narrow distribution (10-20 nm) are highly dispersed both on the edge and between the layers of RGO. And then it was used as a support to load different low contents (no more than 0.4 wt%) of Pt via sacrificial Cu adlayers. The morphology and the electrocatalytic activity of the prepared catalysts were characterized by TEM and cyclic voltammograms (CV), respectively. The results indicate that a small amount of isolated Pt atoms show low or even no activity for methanol oxidation. With the increasing deposition cycles, the content of Pt and the ensembles of neighboring Pt atoms are increased, which makes the onset potential shift negatively and mass current density increase. The results demonstrate that controllable amount of Pt can be deposited on WC/RGO by galvanic displacement with Cu, and the extent and domain of Pt loading affect the electrochemical performance. Meanwhile, this research also provides another route to prepare a catalyst with ultra low noble metal on WC/RGO for solving the problem of high cost of the catalyst. [ABSTRACT FROM AUTHOR]

The composite microwave absorbing coatings reinforced with carbonyl iron nanoparticles were systematically studied. The morphologies of Fe–Si–Al powders (FSA), carbonyl iron nanoparticles (nmCIP) and the corresponding composite coating sections were characterised by scanning electron microscope (SEM) and transmission electron microscope (TEM). The electromagnetic performances of the microwave absorbents mentioned above were measured by vector network analyser and vibrating sample magnetometer, and the corresponding attenuation mechanisms ofthe absorbents were discussed. The composite coatings with polyurethane as matrix were fabricated by employing carbon black, FSA and nmCIP as absorbents. Moreover, the microwave absorption properties of these composite coatings with different absorbents were measured by the arch method. Results showed that nmCIP was an efficient magnetic loss absorbent with lowdensity. The microwave absorption properties of the coatings were significantly enhanced: the peak value of reflection loss (RL) reached -25.8 dB, and bandwidth (RL<-10 dB) was expanded to 3.6 GHz. While it was composited with FSA, which had the same loss mechanism with nmCIP, the location of effective absorption band could be modified with reduced areal density. [ABSTRACT FROM AUTHOR]

The article focuses on the usefulness of cryogenic focused ion beam (FIB) technology with scanning electron microscope (SEM) for analyzing the failure of compound semiconductors which allows gallium FIB milling at room temperature. It discusses the preparation of transmission electron microscope (TEM) lamella from indium nitride (InN) nanoparticles and mentions the FIB milling and cryogenic SEM in one system allowing in situ "mill and view" at high resolution at cryogenic temperatures.

A simple preparation process for the monodispersed pH-sensitive core-shell magnetic microspheres was carried out consisting of chitosan self-assembled on magnetic iron oxide nanoparticles. Meanwhile, glucoamylase was immobilized as a model enzyme on this carrier of FeO/CS microspheres by ionic adsorption. The morphology, inner structure, and high magnetic sensitivity of the resulting magnetic chitosan microspheres were studied, respectively, with a field emission scanning electron microscope (SEM), transmission electron microscope (TEM), FT-IR spectroscopy, thermogravimetric analysis (TGA), and a vibrating sample magnetometer (VSM). Subsequently, the properties of glucoamylase immobilized on the regenerated supports were also investigated by determining storage stability, pH stability, reusability, magnetic response, and regeneration of supports. The results from characterization and determination remarkably indicated that the immobilized glucoamylase obtained presents excellent storage stability, pH stability, reusability, magnetic response, and regeneration of supports. Therefore, this kind of magnetic FeO/CS microspheres with perfect monodispersity should be an ideal support for enzyme immobilization. [ABSTRACT FROM AUTHOR]

Abstract: By means of a facilely designed strategy, we successfully fabricated the multilayer and conductive organo-silica/polystyrene/polyaniline (organo-silica/PS/PANi) composite particles. First, organo-silica/PS core/shell composite particles were synthesized by seeded emulsion polymerization and the vinyl groups located on the surface of organo-silica nanoparticles were used to induce in situ polymerization of styrene. The influence of the route of the addition of styrene on the morphology of organo-silica/PS composite particles was investigated. Then, the coating of organo-silica/PS composite particles with PANi was achieved by virtue of the “Swelling–Diffusion–Interfacial-Polymerization Method” (SDIPM). The whole preparation process was monitored by transmission electron microscope, scanning electron microscope, Fourier transform infrared, Raman spectroscopy, dynamic light scattering, and thermogravimetry. As a result, the multilayer and conductive organo-silica/PS/PANi nanocomposites possessed of a uniform size and well-defined morphology, and furthermore, their structure could be well controlled by simply changing the weight ratio of aniline/PS. [Copyright &y& Elsevier]

Abstract: A new synthesis method of α-Fe2O3 nanoparticles was developed, in which the ferrous and ferric salts as well as polyaniline acted as the precursor and dispersant, respectively. From the investigation of X-ray diffraction and FT-IR spectra, the α-Fe2O3 nanoparticles can be directly prepared by the co-precipitation method without high-temperature calcining. Transmission electron microscope (TEM) and scanning electron microscope (SEM) observation revealed that the α-Fe2O3 nanoparticles had average diameters ranging from 30.0 to 75.0nm. Compared with previous methods, this present method shows an easy processing and can be applied on the large-scale produce of α-Fe2O3 nanoparticles in one step. [ABSTRACT FROM AUTHOR]

Abstract: SiC/SiO2 core–shell nanoparticles were firstly successfully synthesized by using a novel route of thermal CVD and thermal annealing process. The properties of the nanoparticles were characterized by scanning electron microscope, Transmission electron microscope, and X-ray diffraction. A possible growth mechanism was proposed for the nanoparticles according to the characterization results. The photoluminescence spectrum of the untreated nanoparticles revealed broad visible luminescence emission band. After the annealing treatment, the nanoparticles showed good blue emission, indicating potential applications in blue-light optoelectronic devices. [Copyright &y& Elsevier]

PVC/nano CaCO3 composites were prepared on Brabender Plasticorder. For comparison purposes, commercial CaCO3 composites were also prepared. Characterization of the nano CaCO3 and nanocomposites were done using scanning electron microscope (SEM) and transmission electron microscope (TEM). Their mechanical and thermal properties were also studied. Exfoliation was observed with the addition of different sizes of nano CaCO3 filled in PVC composites. Best properties were observed with 9 nm CaCO3 PVC composites. Tensile strength and modulus improved significantly even though the amount of addition of nano filler is low. Thermal properties of PVC/nanocomposites were found to be better compared to that of commercial filled CaCO3 in PVC composites. [ABSTRACT FROM AUTHOR]