Energy Dispersive X-ray Spectroscopy Research Articles

Proteomic analysis of Trichoderma harzianum secretome and their role in the biosynthesis of zinc/iron oxide nanoparticles.

The fungal green synthesis of nanoparticles (NPs) has gained great interest since it is a cost-effective and easy handling method. The process is simple because fungi secrete metabolites and proteins capable of reducing metal salts in aqueous solution, however the mechanism remains largely unknown. The aim of this study was to analyze the secretome of a Trichoderma harzianum strain during the mycobiosynthesis process of zinc and iron nanoparticles. Different profiles of proteins secreted by the fungus grown in the culture media or in the aqueous filtrate were observed through SDS‒PAGE and LC‒MS/MS analysis identifying 99 and 304 proteins, respectively. Particularly, in the aqueous filtrate proteins of metabolic processes and stress response mainly oxidoreductases, were identified. Successfully, ZnO and FeO NPs were synthesized and characterized by transmission electron microscopy, energy dispersive X-ray spectroscopy, dynamic light scattering, thermogravimetric, and FTIR analysis. FTIR revealed organic compounds in nanoparticles acting as probably capping agents. This research is the first report in which a proteomic analysis identifies multiple enzymes involved in the biogenic process of NP biosynthesis from T. harzianum, and its role is clearly demonstrated by the formation of zincite and magnetite nanoparticles.

High-Performance Ti3C2Tx-MXene/Mycelium Hybrid Membrane for Efficient Lead Remediation: Design and Mechanistic Insights.

This study presents a hybrid microfiltration technology designed for high-performance lead (Pb(II)) remediation, especially from aqueous solutions with high Pb(II) concentrations, by utilizing two-dimensional (2D) Ti3C2Tx-MXene layers deposited on dry mycelium membranes. The hybrid Ti3C2Tx-MXene/mycelium (MyMX) membranes were fabricated via a single-step electrochemical deposition (ECD) technique, which enabled a uniform coating of 2D Ti3C2Tx-MXene onto individual hyphal fibers of a prefabricated mycelium membrane. Optimized ECD parameters for high Pb(II) uptake were identified using scanning electron microscopy and energy-dispersive X-ray spectroscopy. In immersion-based (no-flow) Pb(II) remediation experiments, MyMX membranes demonstrated significantly high Pb(II) removal efficiency (>87-99%) and rapid sorption kinetics across an initial Pb(II) concentration range of 60-1500 ppm in both single-ion and co-ion solutions. The enhanced Pb(II) sorption was attributed to electrostatic interactions and surface complexation assisted by hyphal surface proteins and Ti3C2Tx-MXene functional groups, as confirmed by infrared and X-ray photoelectron spectroscopies. In cross-flow studies, the MyMX membranes achieved a Pb(II) sorption capacity of ∼1347 mg/g while maintaining a high permeation rate of 51,800 L m-2 bar-1 h-1 at 1500 ppm Pb(II), surpassing the performance of various polymer-based and MXene-based microporous membranes for heavy metal remediation. The biomaterial-based hybrid MyMX membrane represents a significant advancement in water treatment technology, providing a cost-effective, sustainable solution for Pb(II) remediation in contaminated water sources.

Structural Characterization of the Platinum Nanoparticle Hydrogen-Evolving Catalyst Assembled on Photosystem I by Light-Driven Chemistry.

Directed assembly of abiotic catalysts onto biological redox protein frameworks is of interest as an approach for the synthesis of biohybrid catalysts that combine features of both synthetic and biological materials. In this report, we provide a multiscale characterization of the platinum nanoparticle (NP) hydrogen-evolving catalysts that are assembled by light-driven reductive precipitation of platinum from an aqueous salt solution onto the photosystem I protein (PSI), isolated from cyanobacteria as trimeric PSI. The resulting PSI-NP assemblies were analyzed using a combination of X-ray energy-dispersive spectroscopy (XEDS), high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), small-angle X-ray scattering (SAXS), and high-energy X-ray scattering with atomic pair distribution function (PDF) analyses. The results show that the PSI-supported NPs are approximately 1.8 nm diameter disk-shaped particles that assemble at discrete sites with 145 Å separation. This separation is too large to be consistent with NP nucleation and growth at a site adjacent to the FB cofactor site. Instead, we suggest a mechanism for NP growth at hydrophobic sites on the PSI stromal surface. The NPs photoreductively assembled on the PSI stromal surface are found to be analogous to the nanostructures produced by successive cycles of atomic layer deposition (ALD) of platinum onto 40 nm porous anodic alumina oxide supports, although the mechanisms for nucleation appear to differ. This work establishes a foundation for the investigation of the reductive assembly of abiotic metal catalysts at sites connected to photochemically reducing equivalent production in PSI.

The effect of plasticizers on rheological, physical and mechanical properties of low cement high alumina gunning refractories

In this research, the effect of different plasticizers with different amounts on the properties of monolithic alumina-based refractories has been investigated. All samples were fired at 1100 °C and 1550 °C. In order to evaluate the desired properties, first the rheological properties of the samples were examined, and then for further investigations, loss on ignition (LOI), percentage of permanent linear changes (PLC), apparent porosity (AP), bulk density (BD) and cold crushing strength (CCS) tests were used. In addition, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and X-ray diffractometry (XRD) were used to characterize the samples. 1 and 2 wt% of CMC, H19, bentonite and ballclay were added to the mixtures as plasticizers. The results of this research showed that the sample containing 1 wt% of ball clay can be the most appropriate one due to its highest strength, highest density and lowest apparent porosity. Moreover, the sample containing 2 wt% of H19 (a commercially available binder) has the optimum properties because of its highest strength for the samples fired at 1100 °C. For the mixtures fired at 1550 °C, the more amount of silica has caused higher cold crushing strength due to the presence of the low melting point phases which are not desired and therefore, the mixtures with less silica can be used.

Catalytic efficiency of GO-PANI nanocomposite in the synthesis of N-Aryl-1,4-Dihydropyridine and hydroquinoline derivatives

In this research, graphene oxide-polyaniline (GO-PANI) nanocomposite was successfully synthesized and its catalytic performance was evaluated for the synthesis of N-aryl-1,4-dihydropyridine (1,4-DHP) and hydroquinoline derivatives. The GO nanosheets were prepared using the Hummers’ method, and in-situ polymerization of aniline was conducted with ammonium persulfate (APS) serving as the polymerization initiator. The synthesized nanocomposite demonstrated notable efficiency, achieving yields of 80–94% for 1,4-DHP derivatives and 84–96% for hydroquinoline derivatives. The GO-PANI nanocomposite was thoroughly characterized by various techniques, including Fourier Transforms Infrared spectroscopy (FT-IR), Field Emission Scanning Electron Microscopy (FE-SEM), X-ray Diffraction analysis (XRD), Thermogravimetric analysis (TGA), and Energy Dispersive X-ray spectroscopy (EDS), all of which confirmed the successful synthesis of the nanocomposite. Furthermore, after ten cycles of reusability testing, the nanocomposite retained its high catalytic performance with no significant degradation. This findings indicate that the GO-PANI nanocomposite is a promising non-metal catalyst for the synthesis of N-aryl-1,4-dihydropyridine and hydroquinoline derivatives.

Advanced flame-retardant biocomposites: Polylactic acid reinforced with green gallic acid‑iron‑phosphorus coated flax fibers.

This study introduces a sustainable approach for enhancing the fire retardancy and smoke suppression of poly(lactic acid) (PLA) composites, contributing to addressing one of the major challenges in biocomposites that limits their application in various engineering fields, as automotive and construction sectors. Flax fibers (FF) were surface functionalized with a novel organic-inorganic hybrid flame retardant (FR), offering a sustainable bioinspired approach that mitigates potential mechanical properties impairment and FR leaching, which can cause environmental concerns and reduced composite durability. The process involves a three-step coating procedure. First, the flax fibers (FF) are pretreated with ozone to promote carboxylic group formation (FF-O3); subsequently, gallic acid (GA) units are covalently immobilized on the fiber surface (FF-GA); finally, the hybrid FR iron phenylphosphonate is complexed with the phenolic groups of GA units (FF-GA-FeP). Fourier transform infrared (FT-IR) analysis of FF-GA-FeP confirmed the presence of specific absorptions associated with the deposited FR coating. Scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS) revealed changes in fiber morphology and confirmed the incorporation of iron and phosphorus. Solid-state nuclear magnetic resonance (SSNMR) spectroscopy and X-ray WAXS microscopy revealed that fibers' crystallinity was not significantly affected by derivatization. Microwave plasma atomic emission spectroscopy (MP-AES) detected a precise 0.1 wt% iron loading. Using FF-GA-FeP as reinforcement in PLA-based composites (PLA/FF-FeP) resulted in enhanced thermal stability and flame retardancy of the composites, with minimal coating application, as revealed by thermogravimetric analysis (TGA) and cone calorimetry tests (CCT). A decrease in peak of heat release rate (pHRR), total smoke release (TSR), specific extinction area (SEA), and Fire Propagating Index (FPI) of 5, 87, 68, and 9.5 %, respectively, was achieved for PLA/FF-FeP, compared to untreated flax fiber reinforced PLA (PLA/FF). Furthermore, preliminary tensile tests indicate minor changes in tensile strength and a slight increase in stiffness of the PLA/FF-FeP compared to PLA/FF. Hence, in the biocomposite, the immobilization of a minimal amount of iron phenylphosphonate directly on the flax fiber surface proved to be an effective strategy for smoke suppression while preserving the mechanical integrity of the composite.

Molecular beam epitaxial step-edge growth of integrated hetero-structures: Bi2Te3/multi-stepped Sb2Te3 nanoplate

Abstract We report the synthesis of multiple Bi2Te3 shells on multi-stepped Sb2Te3 nanoplates using molecular beam epitaxial (MBE) step-edge growth. For the growth of Bi2Te3/Sb2Te3 hetero-structures, multi-stepped Sb2Te3 nanoplates with stair-like morphology following layer-by-layer (LBL) growth mode were obtained by optimizing the growth temperature, and the growth of Bi2Te3 on the step-edges of the Sb2Te3 nanoplates was followed. Width of Bi2Te3 on the Sb2Te3 nanoplates was controlled by changing the growth time. Structural properties of the hetero-structures were investigated using aberration-corrected (Cs-corrected) high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), revealing the interface between Sb2Te3 and Bi2Te3. In-plane epitaxial relation at the interface was confirmed using fast Fourier transforms (FFTs). Compositional analysis of Bi2Te3 and Sb2Te3 was verified through energy-dispersive X-ray spectroscopy. Furthermore, we performed density functional theory (DFT) calculations to confirm the preferential growth of Bi2Te3 on the step-edges of Sb2Te3. By forming multi-stepped core structure, it would be feasible to create various integrated hetero-structures.

Degradation rates and ageing effects of UV on tyre and road wear particles.

Tyre and road wear particles (TRWPs) are estimated to be the largest source of microplastics in the environment and due to the intrinsic use of tyres in our society this will continue to grow. Understanding their degradation mechanisms and subsequent accumulation over time is important to gain insights into the fate and impact of these particles in the environment. Accelerated UV-ageing was performed on cryomilled tyre tread particles and TRWPs from a road simulator to investigate the abiotic degradation of rubber. Degradation was followed with thermogravimetric analysis (TGA) that led to an average abiotic degradation rate of 0.025 day-1 when corrected for the acceleration factor. Static light scattering (SLS) showed that during degradation, the average particle size reduced by 0.03μm day-1 and smaller particles <10μm were formed. Further characterisation with scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDX) confirmed these findings and showed that the sulphur content is reduced through UV-ageing suggesting that crosslinking breakage may be a mechanism of degradation. Analysis with gas chromatography and mass spectrometry (GC-MS) showed a substantial decrease in chemical additives by UV-induced oxidation and breakdown. Finally, with measurements in the field TRWP particle sizes and accumulation times were studied, confirming the experimentally determined degradation mechanisms.

Development of a phosphoaminopyrazine-loaded cellulose nanoparticle drug delivery system for targeted treatment of triple-negative breast cancer.

This study explores the development of a sustainable drug delivery system using cellulose nanoparticles (CNPs) derived from potato pulp for the controlled release of phosphoaminopyrazine (PAP), a promising anticancer agent. CNPs were synthesized via nanoprecipitation, and PAP was loaded through in-situ nanoprecipitation, achieving a high loading efficiency of 79.2 %. Characterization of CNPs and PAP-loaded CNPs (PAP@CNP) using Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and thermogravimetric analysis (TGA) confirmed the structural integrity, spherical morphology (45.33 nm for CNPs, 54.6 nm for PAP@CNP), and enhanced thermal stability of PAP@CNP. In vitro, drug release studies demonstrated sustained release over 48 h, with pH-sensitive kinetics favoring the acidic tumor microenvironment. Cytotoxicity assays revealed superior efficacy of PAP@CNP against triple-negative breast cancer cells (MDA-MB-231; IC50 = 20.86 ± 0.81 μg/mL) compared to cisplatin while showing minimal toxicity to normal human umbilical vein endothelial cells (HUVECs). Cellular uptake studies using epifluorescence microscopy and flow cytometry confirmed time-dependent internalization and intracellular drug release. Potato pulp, an abundant agro-industrial waste, as a renewable source for CNPs highlights this approach's economic and environmental advantages. This study demonstrates the potential of potato pulp-derived CNPs as a sustainable and cost-effective platform for targeted cancer therapy; offering improved therapeutic outcomes and reduced environmental impact.

Elimination of Ni(II) from wastewater using metal-organic frameworks and activated algae encapsulated in chitosan/carboxymethyl cellulose hydrogel beads: Adsorption isotherm, kinetic, and optimizing via Box-Behnken design optimization.

The study investigated the enhancement of stability and efficacy in the removal of bivalent nickel ions (Ni(II)) by utilizing a cerium metal-organic framework (Ce-MOF) encapsulated within a food-grade algal matrix. This composite material is integrated into a dual-layer hydrogel containing chitosan and carboxymethyl cellulose. The enhancement of structural integrity in the final product can be attributed to the cross-linking process with epichlorohydrin, leading to the development of Ce-MOF-FGA/CMC-CS hydrogel beads. A comprehensive characterization of the adsorbent was conducted utilizing various analytical methods. These included X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDX), nitrogen adsorption/desorption isotherm analysis, and field emission scanning electron microscopy (FESEM), all aimed at clarifying the textural characteristics of the material. The investigation also explored the effects of multiple variables, including dosage, pH, temperature, and initial concentration, on the adsorption process. The study conducted equilibrium analyses alongside kinetic evaluations to assess the adsorption characteristics. The results demonstrated that the adsorption behavior aligned with the principles of pseudo-second-order kinetics and was suitably described by the Langmuir isotherm model. The data showing heightened metal adsorption as temperatures increase suggests that the adsorption process is characterized by both endothermic properties and spontaneity. In order to determine the most favorable conditions for adsorption, the Box-Behnken design software was utilized. The findings indicate that the optimal conditions include a pH of 5, a dosage of 0.02 g of Ce-MOF-FGA/CMC-CS hydrogel beads for every 25 mL of solution, and an adsorption capacity of 301.05 mg/g specifically for the Ni(II) solution. To optimize the performance of the adsorbent in the removal of Ni(II) during water purification, it is essential to take into account several key variables. The adsorption efficiency was significantly improved by conducting a series of methodically planned experiments, employing the Box-Behnken design alongside response surface methodology, as supported by Design-Expert software. An in-depth evaluation of the adsorbent's reusability carried out over six successive cycles of adsorption and desorption, indicates a significant stability in its removal efficiency.

Effect of doping Mn ion on the crystal structure and cation distribution in Co1-xMnxFe2O4 compounds

In this study, we investigated the effect of Mn doping on the crystal structure and the distribution of cations at tetrahedral and octahedral sites in Co1-xMnxFe2O4 compounds (0 ≤ x ≤ 0.4), synthesized utilizing a solid phase reaction method, utilizing X-ray diffraction (XRD) and Raman spectroscopy measurements. The surface morphology and chemical composition of the compounds were studied using scanning electron microscope and X-ray energy dispersive spectroscopy. The Rietveld refinement of XRD data using the Fullprof package demonstrate that all studied samples are single phase spinels with no other detectable phases and have a cubic structure with the space group of Fd-3 m. The lattice constant and unit-cell volume increased with increased Mn doping concentration, which are attributed to the larger ionic radius of Mn in comparison with Co. Both the X-ray diffraction and Raman spectroscopy results demonstrated that doping Mn at the Co-site leads to the movement of Fe cations from the tetrahedral sites to the octahedral ones.

Dual-stimuli-responsive carboxymethyl chitosan/sodium lignosulfonate microcapsules from oppositely charged biopolymers for smart pesticide release.

In this study, we constructed a pH/laccase dual responsive drug delivery system, denoted as IMI@(CMCS+SL)n, capable of modulating wall thickness and drug release via the layer-by-layer deposition of carboxymethyl chitosan (CMCS) and sodium lignosulfonate (SL). The IMI@(CMCS+SL)n microcapsules was characterized by Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), (energy-dispersive X-ray spectroscopy) EDS, X-ray photoelectron spectroscopy (XPS), and dynamic light scattering techniques (DLS) analysis. IMI@(CMCS+SL)n demonstrated not only a high loading capacity (exceeding 90 %) but also exhibited exceptional performance in sustained release and anti-termite activity of IMI. Significantly, IMI@(CMCS+SL)n was responsive to both laccase and pH variations. These results suggest that the distinctive laccase activity and weakly alkaline conditions within the termite gut may serve as triggering factors for the release of IMI by IMI@(CMCS+SL)n. Overall, the pesticide carrier system designed in this research ensures precise pesticide application and enhances the value of natural biomass resources.

Investigation into Alzheimer's-related amyloid-β conformational transformations and stability influenced by green iron oxide nanoparticles (GIONP).

Alzheimer's disease (AD) is popularly believed to be triggered by the aggregation of amyloid beta 1-42 (Aβ-42) peptides, eventually leading to neurodegeneration. Our study delves into the influential role played by Green Iron Oxide Nanoparticles (GIONP). GIONP are typically synthesized using a green chemistry approach, imposing curcumin as a biocompatible reducing and capping agent, leveraging its inherent antioxidant, anti-inflammatory, and neuroprotective attributes. Herein, our research particularly aims to decipher whether GIONP modulates the secondary structure of Aβ1-42 peptides with a close consideration to the surrounding physiological factors, as well as the membrane bilayer probable conformation changes. Raman spectroscopy was employed to investigate the interaction between GIONP and Aβ1-42 aggregates, demonstrating significant alterations in secondary structure dynamics of Aβ1-42 polypeptide. Fourier-transform infrared (FTIR) spectroscopy shed light on the chemical interactions between GIONP and curcumin, a capping agent. X-ray diffraction (XRD) analysis was performed to determine the crystalline structure and phase purity of the synthesized GIONP, providing insights into their stability and structural integrity. GIONP particle size distribution investigations and membrane architectures surrounding GIONP were carried out for their impact on membrane integrity and stability. The morphology of GIONP, membrane mimetic liposomal structures formation, and integrity were studied using transmission electron microscopy (TEM), accompanied with energy-dispersive X-ray spectroscopy (EDS), which displayed the elements distribution within each of the structures. The study uncovered that GIONP stabilizes the secondary structure of Aβ1-42, potentially offering modulation to the aggregation process. Furthermore, GIONP proved to have no negative impact on membrane integrity, implying that they could be safely employed as a therapeutic option for the modulation of peptide aggregation's pathological pathway of Alzheimer's disease. This study may contribute to broadening our understanding of nanoparticle-mediated therapies in modulating neurodegenerative disorders, highlighting their dual involvement in amyloid aggregation regulation and membrane structure maintenance.

Evaluation of the corrosion resistance of bronze patina or/and protective coating on the surface of the archaeological coins

Archaeological coins are considered essential sources of historical documentation. Over time, they are subjected to corrosion processes that gradually alter their appearance, shape, and composition. This study aims to evaluate the effects of the patina and/or protective coating on the corrosion process. Protection of the original coin surface was crucial following the completion of the cleaning protocol. Various finishes of coin fragments (uncoated, aged, and freshly coated) were investigated to determine their chemical composition, nature of the patina, and corrosion products on their surface using stereo microscopy(SM), X-ray diffraction (XRD), and scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDX). The analysis revealed that the coins were composed of a Cu–Sn- and Pb bronze alloy. Furthermore, the efficiency of the patina and/or protective coatings on the coin fragments was evaluated using potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV) techniques. The highest protection was achieved for patinated-freshly protective coated fragments, while the most corrosive fragments were those affected by bronze diseases.

Characteristics of Ra-226 particles from legacy contamination and implications for radiological protection.

Radioactive particles are physically discrete sources of radioactivity that have been released into the environment as result of past accidents, incidents, and practices, and can present a hazard to members of the public. The historical use of radium in the luminising of aircraft components, and the subsequent decommissioning of those aircraft and associated waste disposal practices, has left a legacy of contamination, such as the radioactive particles containing Ra-226 at Dalgety Bay, Scotland. The aim of this research was to physically, chemically, and radiologically characterise Ra-226 particles from Dalgety Bay and consider the implications for radiological protection of the public. Physical characterisation measured particle size and shape using optical macroscopy with image analysis, measured particle mass, and calculated particle density, as well as general observations on their physical appearance. Chemical characterisation used scanning electron microscopy with energy dispersive X-ray spectroscopy to measure surface elemental composition, and gamma spectrometry was used to measure the activities of Ra-226 and its gamma-emitting daughter radionuclides. Qualitative observations on visual appearance indicated there were five distinct subpopulations, and measurements of size, shape and density varied widely. A wide range of surface chemical compositions were observed, and evidence of their estuarine origin was visible in the form of sand grains and salt deposits. Ra-226, Pb-214, Bi-214 and Pb-210 were detected in all samples with activities over several orders of magnitude and varying degrees of secular equilibrium. Two original aircraft artefacts were also included in the investigation, comparison with which showed the particles and artefacts differed in their characteristics, indicating that the source material has undergone alteration. The diversity of particle characteristics has implications for the radiological protection of the public from Ra-226 particles including pathways of exposure, assessment of radiation dose, and longevity in the environment.

Optimizing the properties of In-N dual-doped SnO2 films: incorporation of nitrogen into the SnO2 lattice at the optimal content via direct current sputtering.

Direct current magnetron sputtering was employed to fabricate In-N dual-doped SnO2 films, with varying concentrations of N2 in a mixed sputtering gas of N2 and argon (Ar). The quantity of N-substituted O elements in the SnO2 lattice was confirmed through energy-dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS). A comprehensive investigation of properties of the In-N dual-doped SnO2 films was conducted using various techniques, including X-ray diffraction analysis, field-emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), ultraviolet absorption spectroscopy, Hall effect measurements, and current-voltage (I-V) characteristic assessments. The results indicated that when the ratio of N2 to the mixed gas (Ar + N2) exceeded 15%, the films exhibited p-type conductivity. The films demonstrated optimal electrical and structural properties at an N2 content of 45%, with a resistivity of 5.1 × 10-3 Ω cm, hole mobility of 12.75 cm2 V-1 s-1, crystal grain size of 25.74 nm, and a root mean square (RMS) roughness of 0.61 nm, resulting in the highest photocurrent at the INTO-45/Si interface.

Superior charge storage performance of optimized nickel cobalt carbonate hydroxide hydrate nanostructures for supercapacitor application

In our work, we report superior electrochemical performance of optimized 3D nanostructured, nickel-cobalt carbonate hydroxide hydrate (Ni3 − xCox-CHH (1 ≤ x ≤ 2)) materials with flower like morphology synthesised via one-step hydrothermal methods. A Ni rich sample (x = 1) demonstrate better specific capacitance and the improvement is attributed to more oxygen deficient neighbourhood of Ni compared to that of Co. The structural, morphological and electronic properties of the samples were investigated using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), High resolution transmission electron microscopy (HRTEM), field emission electron microscopy (FESEM), Energy-dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS). A comprehensive characterization was used for physicochemical properties-electrochemical performance correlation. Cyclic voltammetry (CV), Galvanostatic charging and discharging (GCD) shows the supercapacitor feature of the samples for the composition containing the highest nickel concentration achieving a specific capacitance of 1649.51 F g− 1 at a current density of 1 A g− 1 and excellent rate capability of 1610.30 F g− 1 at a high current density of 5 A g− 1. The sample shows high cyclic stability of 80.86% after 3000 cycles. Improved specific capacitance is attributed to the synergy effect of bimetallic transition metals as well as improved surface area of flower like morphology. These findings show that Ni2Co-CHH electrode material demonstrates great potential as electrode material for supercapacitor device fabrication.

Easy One-Pot Decoration of Graphene Oxide Nanosheets by Green Silver Nanoparticles.

In this study, we developed a facile one-pot synthesis of a nanocomposite consisting of silver nanoparticles (AgNPs) growing over graphene oxide (GO) nanoflakes (AgNPs@GO). The process consists of the in situ formation of AgNPs in the presence of GO nanosheets via the spontaneous decomposition of silver(I) acetylacetonate (Ag(acac)) after dissolution in water. This protocol is compared to an ex situ approach where AgNPs are added to a waterborne GO nanosheet suspension to account for any attractive interaction between preformed nanomaterials. The systems under investigation are characterized by UV/vis absorption spectroscopy, dynamic light scattering (DLS), zeta potential (Z-Pot), and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX). The stability of the AgNPs@GO composite suspension is tested as a function of GO concentration (0-67 μg/mL) while maintaining a constant Ag content (14.4 μg/mL), exhibiting excellent stability over time up to an Ag-to-GO mass ratio of 0.58.

Influence of inclusions on the pitting behavior of cast duplex stainless steels and patch weld layers

Abstract The relationship between the corrosion resistance of cast duplex stainless steel welded joints and inclusions was investigated by metallographic characterization, electrochemical tests, in-situ tests, scanning electron microscopy (SEM) combined with energy dispersive X-ray spectrometry (EDS) and other methods. The results showed that inclusions were the main sites for pitting corrosion initiation in cast 2205 welded joints, and the MnS portion of the composite inclusions preferentially dissolved to form micro-pits, which triggered pitting corrosion. In addition, the density of inclusions in the heat-affected zone (HAZ) was high and the average size of inclusions was larger, resulting in poorer pitting resistance in the HAZ. And pitting was more likely to occur and subsequently a large pit was developed which ultimately leads to failure.

Mechanical properties of (Ba0.4Sr0.4Ca0.2Fe12O19)x/(Bi1.6, Pb0.4)-2223 composite impacted in seawater

In the present work, the effect of adding Ba0.4Sr0.4Ca0.2Fe12O19 hard nanoparticles and the immersion in seawater for different durations (0, 2, 6, 12, and 24 h) on the mechanical characteristics of the Bi, Pb-2223 superconductor phase were studied. A conventional solid-state reaction method was used to produce the (Ba0.4Sr0.4Ca0.2Fe12O19)x/(Bi1.6, Pb0.4)-2223 composites (0.00 ≤ x < 0.40 wt%). X-ray diffraction (XRD) confirmed the primary phase formation of the tetragonal (Bi1.6, Pb0.4)-2223. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) studies were also carried out to demonstrate the microstructural analyses of the samples during seawater immersion. Compared to the pure (Bi1.6, Pb0.4)-2223 phase, SEM and EDX verified the improvement of the adsorption of seawater elements upon adding the nanoparticles. This resulted in faster grain size reduction in the (Bi1.6, Pb0.4)-2223 phase than in the pure sample before immersion. Vickers microhardness () Measurements were performed for 30 s at room temperature, with applied stresses ranging from 0.49 to 9.80 N after immersion in the seawater for different durations (0, 2, 6, 12, and 24 h). For the sample with x = 0.04 wt%, values enhanced with percentages of 67.72% and 98.44%, before and after immersion in seawater for 24 h, respectively. This suggests that the mechanical properties of the (Bi1.6, Pb0.4)-2223 phase were enhanced by a small addition of these nanoparticles and the salts of seawater adsorbed on the sample’s surface. The modified proportional sample resistance (MPSR) model offered the most accurate theoretical analysis in the plateau limit region, before and after seawater immersions, with a less than 5% variance. Furthermore, the incorporation of Ba0.4Sr0.4Ca0.2Fe12O19 into the superconductor had a positive impact on several mechanical characteristics, including fracture toughness (K), yield strength (Y), and elastic modulus (E). All these mechanical parameter values followed the same trend, increasing with the increase in immersion time. However, they are at their height with the presence of 0.04 wt% of these nanoparticles. The toughness increased by 27.31% of the pure sample at this point. After that, when the immersion time rose from 0 to 24 h, this number increased by 42.59%.