Electron Dispersive X-ray Spectroscopy Research Articles

Deposition of Pd, Pt, and PdPt Nanoparticles on TiO2 Powder Using Supercritical Fluid Reactive Deposition: Application in the Direct Synthesis of H2O2.

In this study, we investigated the catalytic properties of mono- and bimetallic palladium (Pd) and platinum (Pt) nanoparticles deposited via supercritical fluid reactive deposition (SFRD) on titanium dioxide (TiO2) powder. Transmission electron microscopy analyses verified that SFRD experiments performed at 353 K and 15.6 MPa enabled the deposition of uniform mono- and bimetallic nanoparticles smaller than 3 nm on TiO2. Electron-dispersive X-ray spectroscopy demonstrated the formation of alloy-type structures for the bimetallic PdPt nanoparticles. H2O2 is an excellent oxidizing reagent for the production of fine and bulk chemicals. However, until today, the design and preparation of catalysts with high H2O2 selectivity and productivity remain a great challenge. The focus of this study was on answering the questions of (a) whether the catalysts produced are suitable for the direct synthesis of hydrogen peroxide (H2O2) in the liquid phase and (b) how the metal type affects the catalytic properties. It was found that the metal type (Pd or Pt) influenced the catalytic performance strongly; the mean productivity of the mono- and bimetallic catalysts decreased in the following order: Pd > PdPt > Pt. Furthermore, all catalysts prepared by SFRD showed a significantly higher mean productivity compared to the catalyst prepared by incipient wetness impregnation.

Synthesis and Antibacterial Activity of Ultrasmall Silver Nanoparticles by Pulsed Laser Ablation in Deionized Water

Background: The main objective of this work is the synthesis and evaluation of silver nanoparticles (Ag NPs) by using pulsed laser ablation of a silver (Ag) target in deionized water and examining their antibacterial activity. Methods: Colloidal solutions of silver nanoparticles were prepared with different pulsed laser energies (620, 880, and 1000) mJ of wavelength 1064 nm and frequency 10 Hz. To determine their structure, optical, morphology, elemental composition, and infrared spectra, the synthesized Ag NPs were characterized using various high-throughput analytical techniques such as (UVVis) spectroscopy, transmission electron microgram (TEM), electron dispersive X-ray spectroscopy (EDX), Fourier transform infrared (FTIR) spectra, and Zeta potential. Results: The results show that the properties of synthesized Ag NPs depend much more on the laser energy. The laser energy can be used to control the properties of the prepared nanoparticles. Uniform distributions of spherical ultrasmall Ag NPs with an average size of (3) nm were obtained suspended in deionized water, which is the most effective size for antibacterial activity. However, the result indicated that the ablated Ag NPs were stable for 4 months in deionized water. The antibacterial activity of the colloidal solution of synthesized Ag NPs against Gramnegative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus) bacteria was then examined using the agar-well diffusion method. Conclusion: It was found that the prepared nanoparticles exhibited strong activity against E. coli and S. aureus bacteria growth. The average zones of inhibition of Ag NPs were found to be about (26) mm for E. coli and (32) mm for S. aureus bacteria.

Corrosion inhibition of martensitic stainless steel by sodium benzoate in acidic medium: Solanum tuberosum extract as surfactant

Research on corrosion inhibitor efficacy has been seen as essential to enhancing the robustness of martensitic stainless steel (MSS), which finds use in a variety of industrial settings. Thus, the aim of this study is to examine the inhibitory efficacy of sodium benzoate with solanum tuberosum (potato) extract as surfactant in a 0.5 M HCl solution for MSS. The techniques of electrochemical measurements and weight loss were adopted for the MSS samples cut into corrosion coupons and submerged in 0.5 M HCl solution at room temperature. A scanning electron microscopy equipped with an electron dispersive x-ray spectroscopy (SEM-EDS) was utilized for the morphology analyses of the samples. From the obtained results, the maximum inhibition efficiency of 32.58 % was recorded at 1.0 M inhibitor concentration, indicating that sodium benzoate is an effective corrosion inhibitor. It was noticed that the rise in the inhibitor concentration up to 1.0 M results in the reduction on corrosion rates being recorded, hence, the inhibition performance. However, 1.5 M and 2.0 M inhibitor concentration had higher corrosion rates compared to others. This study demonstrated that the inhibitor produces a film which adhere strongly to the MSS surface based on the Langmuir adsorption isotherm. Consequently, the combination of sodium benzoate with solanum tuberosum extract would be beneficial to significantly prolong MSS in industrial applications like oil drilling rigs, heat exchangers and marine installations.

Investigation of tool wear and energy consumption in machining Ti6Al4V alloy with uncoated tools

This research studies the energy consumption and wear mechanism of carbide cutting tools in dry machining of Ti6Al4V alloy. In the first phase of experiments, full factorial design experiments were employed to study the tool wear rate (R) and specific cutting energy (SCE) with respect to the machining conditions (cutting speed and feed rate). Results showed that machining responses such as tool wear and energy consumption are affected by cutting conditions, thus requiring investigation to understand the wear mechanisms. Therefore, in the second phase, additional experiments were performed to investigate the tool-workpiece interactions at the cutting conditions reported to have low, moderate, and high tool wear. It was revealed that strong adhesion and material transfer between the tool and workpiece caused high wear. Electron dispersive X-ray spectroscopy (EDX) analysis of worn tools showed that the transfer of tungsten (W) and cobalt (Co) to the workpiece and titanium to the tool surface is the primary cause of tool deterioration. As a result, diffusion and dissolution have degraded cutting performance and weakened the tool edge, leading to rapid wear. Furthermore, worn tools resulted in relatively higher energy consumption per unit volume of material removed at the tooltip. The degradation of cutting performance and weakening of the tool edge results in rapid wear and higher energy consumption. The study suggests that minimizing tool wear is crucial for energy reduction, improved sustainability, and cleaner production goals in dry machining of titanium-based alloys.

Electrochemical charge storage performance of (Mn, Ni, Mo, Co, Fe)3O4 high entropy oxide nanoparticles produced via thermal plasma route

Highly complex high entropy metal oxides (HEOs) have several unique characteristics, such as more active sites and material stability that improve the electrochemical charge storage capacity. In this study, HEOs (Mn, Ni, Mo, Co, Fe)3O4 nanoparticles were synthesized using a thermal plasma route and its electrochemical energy storage performance was studied with two distinct electrolytes such as 1 M KOH and NaOH. The X-ray diffraction analysis revealed the phase pure spinel structured HEOs with crystalline size ranging from 13 to 29 nm. Scanning electron microscopy and electron dispersive X-ray spectroscopy results revealed the quasi-spherical morphology and uniform distribution of constitutional cations in the as-synthesized HEOs. The X-ray photoelectron spectroscopy results identified the oxidation states of cations in spinel HEOs. The charge/discharge studies of as-synthesized HEOs showed a specific capacitance of 215 F g-1 /26.9 mAh g-1 at a current density of 2 A g-1 in 1 M KOH electrolyte which is 156 % greater than 1 M NaOH electrolyte. Furthermore, a high capacitance retention of 91 % was achieved after completing 3000 cycles at 10 A g-1 current density which indicates that the HEOs have excellent charge/discharge reversibility. Electrochemical impedance spectroscopy revealed that the solution and charge transfer resistances of HEOs electrodes were 1.04 and 3.2 Ω, respectively. This novel synthesis strategy attempts to overcome the difficulties experienced by established methods for bulk manufacture of phase pure HEOs since thermal plasma method is a rapid and a single-step approach for the bulk production of nanomaterial.

Synthesis of Cu3Fe4V6O24 Nanoparticles to Produce 1,2,3-Triazoles by Azide-Alkyne Cycloaddition Reactions.

This paper presents the fabrication of novel Cu3Fe4V6O24 nanoparticles (NPs) via a facile sol-gel method as efficient nanocatalysts (NCs) to produce azide-alkyne 1,3-dipolar cycloaddition compounds. The effect of the calcination time on the formation of NPs was investigated. The as-prepared NPs were characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR), scanning electron microscopy (SEM), electron-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), and Brunauer-Emmett-Teller (BET) analyses. Cu3Fe4V6O24 NCs were applied to azide-alkyne 1,3-dipolar cycloaddition reactions. The effect of the catalyst loading, temperature, and time of reaction was optimized to improve the efficiency of the NC function by the response surface methodology-central composite design (RSM-CCD) method. In optimal conditions, the yield of the reaction was 96%. In addition, the effect of different solvents on the yield of the reaction was investigated. Moreover, Cu3Fe4V6O24 NPs efficiently catalyze different 1,2,3-triazoles in excellent yields.

Performance assessment of graphene oxide decorated with silver nanoparticles as adsorbent for removal of metformin from water: Equilibrium modeling, kinetic and thermodynamic studies

In the present study, graphene oxide decorated with silver nanoparticles (GO@AgNPs) was synthesized for the effective removal of metformin from water. The prepared GO@AgNPs was characterized by using Fourier transform Infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric-differential thermal analyses (TGA-DTA), scanning electron microscopy (SEM) coupled with electron dispersive X-ray spectroscopy (EDX) and transmission electron microscopy (TEM). Response surface methodology via Box-Behnken design was adopted for optimizing the variables of adsorption of metformin on GO@AgNPs. Under the optimized conditions (contact time = 50 min; pH = 6.5; adsorbent dose = 0.015 g; initial concentration = 50 mg/L) the adsorption capacity and removal efficiency for metformin were 131.7 ±.0.30 mg/g and 99.34% ±.0.33, respectively. The adsorption data obtained at 305, 310, 315 and 320 K were assessed by non-linear adsorption isotherm and kinetic models. Freundlich isotherm model fits best to the measured data. The pseudo second order kinetic equation fits well to the measured kinetic data. The study of impact of temperature on the adsorption demonstrated that the sorption process was endothermic (∆H° = 31.335 kJ/mol; Ea = 32.009 kJ/mol) and spontaneous in nature (∆G° = −11.162, −11.876, −12.537 and −13.268 kJ/mol at 305, 310, 315 and 320 K, respectively). Moreover, the value of sticking probability (S* = 0.00082) illustrated high probability for metformin sticking on the surface of GO@AgNPs. The adsorption/desorption study shows that there was no loss in adsorption capacities upto 6 cycles which demonstrated the effectiveness of GO@AgNPs as a potential adsorbent for remediation of metformin from aqueous system.

Bacterial Metal Accumulation as a Strategy for Waste Recycling Management

Sustainable mechanisms for efficient and circular metal recycling have yet to be uncovered. In this study, the metal recycling potential of seven metal-resistant bacterial species (Deinococcus radiodurans, Deinococcus aerius, Bacillus coagulans, Pseudomonas putida, Staphylococcus rimosus, Streptomyces xylosus and Acidocella aluminiidurans) was investigated in a multi-step strategy, which comprises bioleaching of industrial waste products and subsequent biosorption/bioaccumulation studies. Each species was subjected to an acidic, multi-metal bioleachate solution and screened for potential experimental implementation. Bacterial growth and metal acquisition were examined using scanning transmission electron microscopy coupled to electron dispersive X-ray spectroscopy (STEM-EDS). Two of the seven screened species, D. aerius and A. aluminiidurans, propagated in a highly acidic and metal-laden environment. Both accumulated iron and copper compounds during cultivation on a multi-metallic bioleachate. Our findings suggest that extremotolerant bacteria should be considered for waste recycling operations due to their inherent polyextremophily. Furthermore, STEM-EDS is a promising tool to investigate microbial–metal interactions in the frames of native industrial waste products. To develop further experimental steps, detailed analyses of adsorption/accumulation mechanisms in D. aerius and A. aluminiidurans are required to design a circular metal recycling procedure.

Investigation of the microstructure of He+ ion-irradiated TiBe12 and CrBe12 using ex-situ transmission electron microscopy

Titanium and chromium beryllides, TiBe12 and CrBe12, are materials of potential future importance as neutron multipliers for tritium breeding in nuclear fusion reactors. Beryllium experiences extremely high transmutation according to a n →2n transmutation reaction in which both tritium and helium are produced, which normally form bubbles in solids at the relevant concentration range. Neutron irradiation from the fusion plasma also introduces point defects into solids. The ensuing effect of this environment on the beryllides’ microstructure is poorly characterised, but important for understanding beryllides’ mechanical properties and their evolution in the irradiative environment inside a fusion reactor. This study is intended to initially determine and describe the microstructural features that occur in TiBe12 and CrBe12 when He and fast-particle-induced point defects have been introduced at fusion reactor neutron breeder relevant temperatures. In this study, beryllide samples were implanted with 300 kV He at a range of temperatures between 387 and 900 °C, sectioned down through the implantation surface with a focused ion beam post-irradiation, and the resulting microstructures examined using transmission electron microscopy, electron-dispersive X-ray spectroscopy (EDX/EDS) and precession diffraction mapping.Nanometre-scale bubbles grew in both TiBe12 and CrBe12 at 600 °C and larger (100+ nm) bubbles, some faceted, grew at 900 °C. Some bubbles in CrBe12 were lined with Cr, with some of the Cr oxidised. TiBe12 developed planar faults, on {110} planes at 600 °C and below but on to {111} at 900 °C. Faults were preferentially associated with large bubbles. The displacement vectors of faults on the {110} planes had some commonality with previous studies that found displacement vectors of the two types R=12〈011〉 and R=12〈110〉; the present study also found faults that did not match either previously found type. CrBe12 also developed planar faults but the appearance of these was quite different from the typical striped appearance of planar stacking faults and their nature remains unknown. Oxide particles from manufacture were found in both beryllides, most prominently in CrBe12.

Effect of carbon dots nanomaterial concentration on luminance spectral bandwidth via Kirchoff-Bunsen spectroscope

This study aims to determine the effect of the concentration of Carbon Dots on the bandwidth of the Carbon Dots luminescence spectrum. Carbon Dots are produced by ultrasonification method and characterized using UV-Vis spectroscopy, photoluminescence (PL) spectroscopy, scanning electron microscopy (SEM), electron dispersive X-Ray spectroscopy (EDX), X-ray diffraction (XRD), and particle size analyzer (PSA). Measurement of the bandwidth of the Carbon Dots fluorescence spectrum for various concentrations was carried out by irradiating the Carbon Dots sample using a laser with a wavelength of 405 nm and looking at the spectrum of light emitted using a Kirchoff-Bunsen spectroscope.The characterization results show that the resulting Carbon Dots have a light absorption peak at a wavelength of 303 nm, a light wave emission peak at a wavelength of 508.87 nm, the surface structure of the Carbon Dots is in the form of a porous layer, the presence of the dominance of carbon and oxygen atoms in Carbon Dots, an amorphous Carbon Dots structure is observed, and the smallest measured Carbon Dots particle size is 1.12 nm. The results show that increasing the concentration of Carbon Dots causes a tendency to increase the bandwidth of orange, green and blue light spectra emitted by the particles, and in the red color there was no significant effect of increasing the concentration of Carbon Dots on the spectrum. However, increasing the concentration of Carbon Dots actually causes a narrowing of the yellow and violet color spectra.

Exploring the Potential of Utilizing Aquatic Macrophytes for Enhanced Phytoremediation of Zinc in Artificial Wastewater: Characteristics and Parameter Studies

Heavy metal pollution due to industrialization can threaten the surrounding environment and living organisms. Phytoremediation is a green technique that uses hyperaccumulator plants to eliminate or decrease heavy metals in polluted water bodies. The aim of this study was to investigate the changes in morphology of Pistia stratiotes (water lettuce) and Eichhornia crassipes (water hyacinth) before and after phytoremediation of zinc (Zn) by using scanning electron microscopy (SEM), electron dispersive X-ray spectroscopy (EDX) and Fourier transform infrared spectroscopy (FTIR). The SEM images showed the formation of small granular aggregates on the surfaces of the leaf and root. EDX results confirmed the uptake of Zn metal, especially in the plant roots. The FTIR spectra showed the Zn metal binding with several characteristic functional groups (O-H, C-H and C=O bonds). Different parameters were also studied to optimize the Zn uptake rate. Water lettuce achieved 80.1% phytoremediation of Zn after 5 days at optimum conditions (10 ppm of Zn, 6 ppm of sodium chloride and natural solution pH). Meanwhile, water hyacinth reached up to 88% when increasing the sodium chloride up to 9 ppm. In conclusion, Zn phytoremediation using both plants can be a potential remediation method for improving the quality of water.

Fabrication of zirconium borosilicate glasses using municipal waste ash for radiation shielding applications; optical and structural investigations

In this study, three borosilicate glass systems were successfully prepared by using the melting–annealing technique from municipal waste ash and doped with ZrO2 at 0, 0.1, and 0.3 wt.%. The glasses were analyzed by electron dispersive X-ray spectroscopy (EDX), which indicated their rich compositions with various metal ions, and X-ray diffraction analysis (XRD) confirmed their amorphous glassy nature. The effects of gamma radiation at 80 kGy on the optical, physical, structural, and chemical properties of the glasses were evaluated. The optical spectra contained ultraviolet peaks at 260–340 nm and visible peaks at 440–470 nm due to the different valence states of transition metal ions, e.g., Ti4+/Ti3+, Cu2+/Cu+, Zn2+, Fe3+/Fe2+, and/or Zr4+. The optical band gap energy (Egap) decreased from 2.0 to 1.0 eV and from 2.8 to 1.90 eV for indirect and direct transitions after irradiation, respectively, whereas the linear refractive index (n) increased. Fourier transform-infrared spectroscopy (FTIR) indicated high structural stability against irradiation due to the connected borosilicate network comprising trigonal BO3 and tetrahedral BO4 and SiO4 units. The band at 960 cm−1 in the undoped and 0.1% Zr4+ glasses shifted to 980 cm−1 in 0.3% Zr4+ glass because of the different compositions and silica contents of the glasses. Analysis of the chemical durability of the glasses in H2O at 100 °C indicated their high chemical stability before and after irradiation with a weight loss not exceeding 0.05%. BO3, BO4, SiO4, transition metal ions, and ZrO2 all contributed to the compact structure of the glasses, and their high stability against irradiation indicates the potential applications of the glasses in radiation shielding.

Three-Dimensional Reconstruction of Nb3Sn Films by Focused Ion Beam Cross Sectional Microscopy

Niobium has been the material of choice for SRF cavities for several decades due to its formability and superconducting properties. The accelerating gradient of niobium cavities is, however, rapidly approaching a theoretical limit. To achieve higher accelerating gradients a new material is needed that can sustain high fields. Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Sn is a promising competitor with a higher superconducting transition temperature and a higher critical field than pure niobium. However, Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Sn is very brittle and cannot be formed readily into a cavity. The main method for creating Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Sn cavities is to form a Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Sn film into a niobium surface using a tin vapor-diffusion method. This technique creates a microcrystalline Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Sn thin film on the inner surface of the cavity. Tin depleted regions are known to form in the film during this process. Previous studies have analyzed these regions using transmission electron microscopy on cross-sectional lamellae prepared by focused ion beam/scanning electron microscope (FIB/SEM). This method does not provide any three-dimensional (3-D) information about the distribution of tin-deficient regions. In this study we employ a focused ion beam tomographic technique to analyze the 3-D structure of the film. Electron dispersive X-ray spectroscopy is used to image the tin concentration of the film in 3-D. Tin-deficient regions are discovered close to the surface of the Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Sn film.

Green synthesis of Plectranthus amboinicus leaf extract incorporated fine-tuned manganese dioxide nanoparticles: Antimicrobial and antioxidant activity

Plectranthus amboinicus Manganese dioxide (PA-MnO2) nanoparticles were synthesized by the reduction of potassium permanganate (KMnO4) using Plectranthus amboinicus (P. amboinicus) leaf extract at room temperature. A dark brown colour appeared after the addition of leaf extract to the solution of KMnO4. PA-MnO2 nanoparticles showed absorbance maximum at 324 nm. Scanning Electron Microscopy (SEM) study of particle size and morphology revealed that PA-MnO2 nanoparticles have spherical structures in shape. The electron dispersive X-ray spectroscopy confirmed the presence of Mn and O in the sample. Fourier Transforms infrared spectra of PA-MnO2 nanoparticles show the occurrence of O-Mn-O vibrational mode at around 515 cm-1. Based on the spectral and morphological data confirms the prepared compounds are nanometer in size. The structural investigation of MnO2 nanoparticles using the powder X-ray diffraction method reveals that the nanoparticles have a tetragonal configuration. Powder X-ray diffraction measurements were used to estimate crystallite grain diameter. The size of the crystalline grains is 7.5 nm. The PA-MnO2 nanoparticles demonstrated enhanced antibacterial activity against various gram positive bacteria like as S. aureus, S. pneumoniae, Stap. Pneumoniae and B. subtilis and various gram negative bacterial strains like as E. coli, K. pneumoniae, p. mirabilis and P. aeruginosa than standard drug ciprofloxacin. Antifungal activity of PA-MnO2 nanoparticles exhibited abnormal character against various fungal strains such as A. niger, C. albicans, C. tropicalis and M. campestris than the standard drug nystatin. Free radical scavenging study by DPPH assay showed enhanced activity by increasing the concentration of PA-MnO2. This study shows simple and eco-friendly synthesis of PA-MnO2 nanoparticles by plant extract. PA-MnO2 nanoparticles by green approach have potential to resolve emerging drug resistance against pathogenic diseases.

Effect of Traverse Speed Variation on Microstructural Properties and Corrosion Behavior of Friction Stir Welded WE43 Mg Alloy Joints.

The growing demand for Magnesium in the automotive and aviation industries has enticed the need to improve its corrosive properties. In this study, the WE43 magnesium alloys were friction stir welded (FSW) by varying the traverse speed. FSW eliminates defects such as liquefication cracking, expulsion, and voids in joints encountered frequently in fusion welding of magnesium alloys. The microstructural properties were scrutinized using light microscopy (LM) and scanning electron microscopy (SEM). Additionally, the elemental makeup of precipitates was studied using electron dispersive X-ray spectroscopy (EDS). The electrochemical behavior of specimens was evaluated by employing potentiodynamic polarization tests and was correlated with the microstructural properties. A defect-free weldment was obtained at a traverse and rotational speed of 100 mm/min and 710 rpm, respectively. All weldments significantly improved corrosion resistance compared to the base alloy. Moreover, a highly refined microstructure with redistribution/dissolution of precipitates was obtained. The grain size was reduced from 256 µm to around 13 µm. The corrosion resistance of the welded sample was enhanced by 22 times as compared to the base alloy. Hence, the reduction in grain size and the dissolution/distribution of secondary-phase particles within the Mg matrix are the primary factors for the enhancement of anti-corrosion properties.

Fabrication of CuO (p)–ZnO (n) Core–Shell Nanowires and Their H2-Sensing Properties

Unlike the conventional one-dimensional (1D) core–shell nanowires (NWs) composed of p-type shells and n-type cores, in this work, an inverse design is proposed by depositing n-type ZnO (shell) layers on the surface of p-type CuO (core) NWs, to have a comprehensive understanding of their conductometric gas-sensing kinetics. The surface morphologies of bare and core–shell NWs were investigated by field emission scanning electron microscope (FE-SEM). The ZnO shell layer was presented by overlay images taken by electron dispersive X-ray spectroscopy (EDX) and high-resolution transmission electron microscopy (HRTEM). The pronounced crystalline plane peaks of ZnO were recorded in the compared glancing incident X-ray diffraction (GI-XRD) spectra of CuO and CuO–ZnO core–shell NWs. The ZnO shell layers broaden the absorption curve of CuO NWs in the UV-vis absorption spectra. As a result of the heterostructure formation, the intrinsic p-type sensing behavior of CuO NWs towards 250 and 500 ppm of hydrogen (H2) switched to n-type due to the deposition of ZnO shell layers, at 400 °C in dry airflow.

Biosynthesis of silver nanoparticles from Arum dioscoridis plant leaf aqueous extract: anticancer and antimicrobial properties

This study was carried out to synthesize silver nanoparticles (AgNPs) from Arum dioscoridis (AD) leaf extract and to investigate the cytotoxic and antipathogenic effects of them. The plant material had a reducing and stabilizing effect on the synthesized nanomaterial. During the plant-mediated synthesis of nanomaterials, no substances that would cause environmental pollution were used. For the structural characterization of AD-AgNPs, Ultraviolet-visible (UV-vis) Spectroscopy, Field Emission Scanning Electron Microscopy (FE-SEM), Electron Dispersive X-ray (EDX) Spectroscopy, Fourier Transform Infrared (FT-IR) Spectroscopy, Transmission Electron Microscopy (TEM), X-ray Diffractometer (XRD), Atomic Force Microscopy (AFM) and Zetasizer analyses were performed. The produced AgNPs showed maximum surface plasmon resonance at 431.67 nm and had mostly spherical morphology. The zeta potential value of the nanomaterial was -9.76 mV and the average powder crystal size was 31.48 nm. The minimum inhibitory concentration (MIC) values (mg/L) of AD-AgNPs on Staphylococcus aureus, Escherichia coli, Bacillus subtilis, Pseudomonas aeruginosa, and Candida albicans were 0.25, 2.00, 0.125, 4.00, and 1.00, respectively. After 24 and 48 hours of application by MTT [3-(4,5-dimetiltiazol-2-il)-2,5-difeniltetrazolium bromid] assay, the half-maximal inhibitory concentrations (IC50: μg/mL) of AD-AgNPs on human colon adenocarcinoma cell (CACO-2), human breast cancer cell (MCF-7), glioblastoma multiforme cell (T98-G), and healthy human umbilical vein endothelial cell (HUVEC) lines were determined as 2.977, 2.801, 5.694, 4.392; 2.115, 2.300, 2.612, 4.091, respectively.

Facile fabrication of graphene oxide/zinc selenide nanocomposite for efficient oxygen evolution reaction

The electrolysis of water for substantial production of hydrogen and oxygen with very high purity is considered as a potentially practical technology. In the present study, we have fabricated a graphene-oxide hybrid zinc-selenide electrocatalyst and characterized it using different techniques. XRD analysis confirms the phase purity and crystal structure of the electrocatalyst. Furthermore, the elemental arrangement and morphology of the electrocatalyst were examined by electron dispersive X-ray spectroscopy (EDX) and scanning electron microscopy (SEM). To check the activity of electrocatalysts through electrochemical cyclic voltammetry (CV), linear cyclic voltammetry (LSV), and impedance analysis have represented that catalyst activation occurs at lower applied potential because of the decrease of electro-negativity of the anion. The ZnSe also displayed efficient OER catalytic performance in a basic medium, making it a very energetic bifunctional electro-catalyst for water splitting with a cell voltage of 1.38 V and an overpotential of 155 mV at 10 mA/cm2.

Biofunctionalisation of Polypyrrole Nanowires Array with Sulfite Oxidase Coupled with the Integration of Platinum Nanoparticles for Ultrasensitive Amperometric Detection of Sulfite

Sulfite determination in foods and alcoholic beverages is a common requirement by food and drug administration organisations in most countries. In this study, the enzyme, sulfite oxidase (SOx), is used to biofunctionalise a platinum-nanoparticle-modified polypyrrole nanowire array (PPyNWA) for the ultrasensitive amperometric detection of sulfite. A dual-step anodisation method was used to prepare the anodic aluminum oxide membrane used as a template for the initial fabrication of the PPyNWA. PtNPs were subsequently deposited on the PPyNWA by potential cycling in a platinum solution. The resulting PPyNWA-PtNP electrode was then biofuntionalised by adsorption of SOx onto the surface. The confirmation of the adsorption of SOx and the presence of PtNPs in the PPyNWA-PtNPs-SOx biosensor was verified by scanning electron microscopy and electron dispersive X-ray spectroscopy. Cyclic voltammetry and amperometric measurements were used to investigate the properties of the nanobiosensor and to optimise its use for sulfite detection. Ultrasensitive detection of sulfite with the PPyNWA-PtNPs-SOx nanobiosensor was accomplished by use of 0.3 M pyrrole, 10 U mL−1 of SOx, adsorption time of 8 h, a polymerisation period of 900 s, and an applied current density of 0.7 mA cm−2. The response time of the nanobiosensor was 2 s, and its excellent analytical performance was substantiated with a sensitivity of 57.33 μA cm−2 mM−1, a limit of detection of 12.35 nM, and a linear response range from 0.12 to 1200 μM. Application of the nanobiosensor to sulfite determination in beer and wine samples was achieved with a recovery efficiency of 97–103%.

Stacking-disordered CoSn3 and tetragonally stacked CoSn4 formed during solid-state interdiffusion of Co and Sn

The reactive interaction of Sn-rich solders with transition metals at temperatures close or above the melting point of the Sn leads to formation of stable or metastable intermetallic phases. Adequate microstructure analysis of solder joints relies on correct identification of the phases and their microstructures. The present work, thereby, focusses on the intermetallic forming from Co and Sn under solid-state conditions (150°C–190 °C) in model diffusion couples. The crystal structures and microstructures having developed were characterized using by X-ray diffraction (XRD) and scanning electron microscopy) supplemented by electron-dispersive X-ray spectroscopy and electron-backscatter diffraction (EBSD). While at 190 °C virtually exclusively a CoSn3 layer develops, at 170 °C and 150 °C an additional CoSn4 layer is formed. As evidenced by XRD, both the CoSn3 and CoSn4 having formed here show crystal structures different from previous works. The CoSn3 shows a random stacking of Co2Sn6 double layers, intermediate between the known equilibrium polytypes α-CoSn3 and β-CoSn3. The CoSn4 has the tetragonal β-IrSn4 structure (also I41/acd) with a largely regular stacking of CoSn4 layers (referred to as β-CoSn4), whereas until now a different polytype (orthorhombic α-CoSn4) has been reported. Including also results from first-principles calculations on the stable polytypes, criteria for accurate phase identification by XRD and EBSD methods have been elaborated, involving strategies to reliably distinguish the polytypes of CoSn3 or CoSn4, but also to distinguish (whatever form of) CoSn3 from (whatever form of) CoSn4.