Field Emission-scanning Microscopy Research Articles

BTEX adsorption from aqueous solutions using activated carbon from Melaleuca cajuputi leaves

This study put forward Melaleuca cajuputi leaves to prepare activated carbon using H3PO4 as an activating agent and examined the aqueous solution of benzene, toluene, ethylbenzene and xylene (BTEX). The surface functional group, surface morphology, and surface area were identified by employing Fourier transform infrared spectra, field emission scanning microscopy, and Brunauer-Emmett-Teller to characterize the properties of the produced activated carbon; others include pH, moisture content, and yield percentage. The activated carbon's performance was assessed using batch adsorption experiment. 50 mg/L of BTEX disintegrates in purified water to form the standard solution and is stored at 4 °C. The study examined the effects of time spent in contact, dosage of the adsorbent and initial concentration. The results show that Melaleuca cajuputi activated carbon (MCAC2) has the optimum surface area 128 m2/g and performs very effectively as a BTEX adsorbent. According to the BTEX adsorption data, MCAC2 has 94% elimination effectiveness at 50 mg/L after 30 min of contact. To further adapt the experimental information for BTEX adsorption onto the MCAC2, Freundlich, Langmuir, and pseudo-first-order and pseudo-second-order models were used. The findings fitted pseudo-second-order with optimal values of R2 = 0.979, and the isotherm model adsorption fitted Langmuir model with values of R2 = 0.992 The finding reveals that Melaleuca cajuputi leaves are useful material for producing adsorbents, and successful testing outcomes demonstrate that M. cajuputi leaves products serves as a vital organic absorbent in the decomposition of BTEX.

Preparation of β-cyclodextrin derivatives/metamizole inclusion complex nanofibers: Characterization, drug release, and wound scratch assay

Nanofibrous wound dressings fabricated by electrospinning have attracted significant research interest as they enable the controlled release of active substances at the wound site. The development of electrospun nanofibers with anti-inflammatory drugs, which demonstrate great potential for wound healing applications, is one of the main focuses of present research efforts. In this study, nanofibrous webs of 2-hydroxypropyl-β-cyclodextrin (HPβCD) and methyl-β-cyclodextrin (MβCD) loaded with metamizole (MMS) were fabricated by electrospinning. The prepared nanofibers were characterized by field-emission scanning electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, thermogravimetric/differential thermal analysis, 1H nuclear magnetic resonance spectroscopy, ultraviolet diffuse reflectance spectroscopy, and photoluminescence analysis. The interactions of HPβCD and MβCD with MMS in aqueous solutions were studied using absorption and fluorescence spectroscopy, and the 1:1 MMS/CD inclusion complexes were theoretically analyzed at the PM3 level of theory. Furthermore, the drug release, biocompatibility, and wound scratch assay of the nanofibers were evaluated. In vitro drug release analysis revealed controllable release of MMS from the nanofibers. The CD nanofibers loaded with MMS showed good biocompatibility with skin fibroblasts. An in vitro wound scratch assay indicated that the nanofibers promoted fast wound closure with a rate of 98.66 ± 3.9%. In summary, the prepared nanofibrous webs are promising candidates for wound-dressing applications.

A new study on the corrosion inhibition mechanism of green walnut husk extract as an agricultural waste for steel protection in HCl solution

In this study, green walnut husk (GWH) extract was explored as a cost-effective (waste-agricultural) and eco-friendly inhibitor to increase the corrosion resistance of carbon steel in a 1 M HCl solution. Electrochemical impedance spectroscopy, weight change, and potentiodynamic polarization (PDP) tests were utilized to examine the electrochemical behavior of steel substrates with and without the inhibitor. Atomic force microscopy (AFM), field emission scanning microscopy, Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) were performed to analyze corroded surface structures with and without the inhibitor. This inhibitor was found to be 27–82 % efficient in increasing the corrosion resistance of the steel substrates. When the temperature of the solution was increased from 303 to 323 K, the retardation coefficient decreased due to the physical adsorption of GWH molecules on the surface. The results indicated that GWH acted as a mixed inhibitor, and its adsorption on the surface followed the Langmuir model. AFM measurements showed that the roughness of corroded surfaces decreased by approximately 22 % when the GWH concentration was at its optimum level of 400 ppm. Thermodynamic studies displayed a decrease in the corrosion reaction's activation energy of about 25 %. FTIR and XRD patterns of corroded surfaces represented that hydrated iron chloride was the dominant corrosion product. Furthermore, the results provided insight into the GWH adsorption mechanism.

Non-enzymatic electrochemical sensor based on ZnO nanoparticles/porous graphene for the detection of hypoxanthine in pork meat

In this study, we developed a pioneering non-enzymatic electrochemical sensor utilizing a flexible porous graphene electrode modified with ZnO nanoparticles (ZnO/fPGE sensor) to assess hypoxanthine (HXA) content in pork at post-mortem time. The ZnO/fPGE sensor was synthesized via hydrothermal method and direct laser writing with a CO2 laser on a polyimide film at ambient conditions. Its characterization was analyzed by Raman, Fourier-transform infrared spectroscopy, field-emission scanning microscopy, energy-dispersive x-ray spectroscopy, and cyclic voltammetric techniques. Linear response, the limit of detection, and sensitivity to the HXA were enhanced with the values of the range from 1.5 to 150, 0.14 µM, and 6.6 µA μM−1 cm−2, respectively. Effective resistance to common physiological interferences (such as uric acid, ascorbic acid, dopamine, glucose, and xanthine) was indicated, and additionally, the determination of HXA concentration in real samples with good selectivity is attributed to the synergistic effects between ZnO nanoparticles and fPGE. Therefore, the ZnO/fPGE has provided a favorable electrical environment for developing high-performance electrochemical biosensors to determine hypoxanthine in pork meat.

Determination of Morphine Using Carboxylated Multiwalled Carbon Nanotubes (MWCNTs) as the Label for an Immunochromatographic Assay (ICA)

This study evaluated the application of carboxylated multi-walled carbon nanotubes (MWCNTs) as a label in immunochromatographic assay for morphine detection. MWCNTs were carboxylated using nitric acid and characterized by Fourier-transform infrared (FTIR) spectroscopy, Raman spectroscopy, field emission scanning microscopy (FESEM), and dynamic light scattering (DLS). The optimum concentration of polyvinyl pyrrolidone (PVP) as a surfactant for homogenous dispersion of MWCNTs was determined by ultraviolet-visible spectroscopy to be 0.5 mg/mL. The zeta potential of MWCNTs before adding PVP was −41.9 ± 1.02 mV, and after adding PVP, −54.1 ± 0.25 mV. On the surface of MWCNTs, the anti-morphine antibody (AM antibody) had a binding effectiveness ranging from 91.1% to 95.5%. The AM antibody-MWCNTs were conjugated to create immunochromatographic test strips. The visual limit of detection (vLOD) was 1.0 ng/mL and the cutoff concentration (COC) was 10.0 ng/mL. Compared to previous study, carboxylated-MWCNTs as a one-dimensional nanomaterial improved the sensitivity of immunochromatographic assay strips and may be utilized to develop the sensitive immunochromatographic assays.

Enhanced strength ductility and wear resistance in a friction stir processing engineered AZ31B/TiC magnesium-based nanocomposites

ABSTRACTIn the present investigation, efforts have been made to fabricate a magnesium-based AZ31B nanocomposite by integrating nano-sized titanium carbide (TiC) particles via utilising the friction stir processing (FSP) process. The primary objective of the research was to enhance the metallurgical, mechanical, and tribological properties of the base material while investigating the influence of secondary phase particles and various FSP parameters. The findings were rigorously validated through a comprehensive analysis, which encompassed the use of various testing apparatus, such as optical microscopy, field emission scanning microscopy, microhardness testers, tensile and compressive testing machines, along with fractography analysis for wear morphology and tensile properties. The results indicate that the nanocomposite produced under the conditions of a tool rotation speed of 1600 rpm and a transverse speed of 40 mm/min along with three number of FSP passes exhibits superior mechanical and tribological properties compared to both other developed composites and the base alloy. A significant enhancement of nearly 2.68 times in microhardness values along with simultaneous refinement in grain size up to 14.85 times was obtained. Ultimate tensile and compressive strengths report an impressive increase in values up to 2.16 and 1.6 times respectively when compared to the base metal. Furthermore, the tensile fracture behaviour of the base magnesium alloy indicated brittleness, while the AZ31B/TiC composite displayed a combination of ductile and brittle features. In terms of wear morphology, the base magnesium alloy exhibited adhesive and abrasive wear, while the composite demonstrated particle pull-out, delamination, and localised plastic deformation, with enhanced resistance to wear. These findings underscore the significant improvements achieved in mechanical and tribological properties, thus emphasising the novel contributions of this research to the field.

Multimode Luminescent Properties from Tb3+-Yb3+ Codoped CaMoO4 for Solar Cell Spectral Conversion

NIR and visible emitting CaMoO4:Tb3+/Tb3+-Yb3+ phosphors were synthesized to harness the energy losses attribute to wavelength mismatch between response spectrum of incident solar photons and solar cells. The X-ray diffraction (XRD), field emission scanning microscopy (FE-SEM), fourier transform infrared spectroscopy (FTIR), UV–vis diffuse reflectance spectroscopy, photoluminescence (PL), up-conversion and life time measurements were used to characterized the prepared phosphors. XRD study followed by Rietveld refinement confirms the tetragonal crystal structure with space group I41a(88). The phosphors exhibit strong green emission (5D4→7F4) in visible region after an excitation wavelengths 378 nm and 980 nm, respectively through down-shifting (DS) and up-conversion (UC) processes. The UV photons (378 nm) are also split it into two NIR photons (2F7/2→2F5/2) through down-conversion process. Fluorescence quenching was observed by increasing concentration of Tb3+ and Yb3+ ions. Lifetime measurements clearly illustrates the energy transfer from Tb3+ to Yb3+ ions and mechanism involved is co-operative energy transfer. The estimated values of energy transfer efficiency (ETE) and corresponding theoretical internal quantum efficiency are achieved as 69% and 169% respectively.

Influence of Zn-substitution on structural, magnetic, dielectric, and electric properties of Li–Ni–Cu ferrites

The polycrystalline Li0.15Ni0.6-xZnxCu0.1Fe2.15O4 ferrites are fabricated by the method of conventional solid-state reaction technique. The X-ray diffraction (XRD) confirms that the structure of the composition is a single-phase cubic spinel structure for all samples. The particle size of the compositions is varied from 36 to 52 nm. The lattice parameter and densities are found to increase with enhancing Zn content, as the ionic radius and atomic weight of Zn are greater than Ni. The porosity exhibits a decreasing trend. The average grain size determined using Field Emission Scanning Microscopy (FESEM) increases until x = 0.40, then declines. The Energy-Dispersive Spectroscopy (EDS) examination revealed that the percentage of obtained elements is well matched with the stoichiometric elements. The addition of Zn content acts as an accelerator for enhancing the value of the real part of initial permeability and the highest value is obtained (μiʹ = 276) for the x = 0.40 sample, as well as the highest relative quality factor (RQF) of around 3000. The loss factor for the Zn substituted composition is nine times lower than for the parent composition. The optimum saturation magnetization of around 77.49 emu/g is found for the x = 0.40 sample. The maximum dielectric constant (εʹ = 2.85 × 103) is found for x = 0.10 samples at 10 kHz. Further, from impedance studies, the non-Debye type dielectric relaxation is seen for the Zn-substituted samples. The observed region of the imaginary electric modulus peak signifies the transition of charge carrier mobility from a larger range to a short-range distance. The phenomenon of ac conductivity is attributed to the process of the small polaron hopping mechanism.

Structural and luminescence studies on thermally stable Bi3+‐activated Ba3MoTiO8 phosphors for near UV‐pumped w‐LED applications

AbstractThis research presents the outcomes of diverse morphological and photoluminescence (PL) studies performed on Bi3+ ion–doped Ba3MoTiO8 phosphors prepared via the conventional solid‐state reaction method. Phase assessment was carried out via the X‐ray diffraction (XRD) studies. Field emission scanning microscopy (FE‐SEM) and energy‐dispersive X‐ray analysis (EDAX) have been used to study the surface morphology anda elemental composition. Fourier transform infrared spectroscopy (FT‐IR) was used to study the character and vibrational frequencies of bonds in the phosphor lattice. Room‐temperature PL was performed under 275 and 386 nm excitations, displaying a broad band in the blue region corresponding to the 3P1 → 1S0 transition of Bi3+ ions. The Commission Internationale de L'Eclairage coordinates and correlated color temperature values show that the as‐prepared phosphors emit in the blue vicinity. The decay curves under both excitation wavelengths show a single exponential behavior. Temperature‐dependent PL studies confirmed the high thermal stability of the phosphor. We want to endorse these phosphors as a blue‐emitting component in white light‐emitting diodes (w‐LEDs) and solid‐state lighting (SSL) applications.

Innovative Preparation of Cellulose-Mediated Silver Nanoparticles for Multipurpose Applications: Experiment and Molecular Docking Studies.

In recent years, inorganic metal nanoparticle fabrication by extraction of a different part of the plant has been gaining more importance. In this research, cellulose-mediated Ag nanoparticles (cellulose/Ag NPs) with excellent antibacterial and antioxidant properties and photocatalytic activity have been synthesized by the microwave-assisted hydrothermal method. This method is a green, simple, and low-cost method that does not use any other capping or reducing agents. X-ray diffraction (XRD), Fourier transform infrared (FTIR), field emission scanning microscopy (FESEM), transmission electron microscopy (TEM), energy-dispersive X-ray (EDX), and UV-visible spectroscopic techniques were used to investigate the structure, morphology, as well as components of the generated cellulose/Ag NPs. In fact, XRD results confirm the formation of the face-centered cubic phase of Ag nanoparticles, while the FTIR spectra showed that the synergy of carbohydrates and proteins is responsible for the formation of cellulose/Ag NPs by the green method. It was found that the green-synthesized silver nanoparticles showed good crystallinity and a size range of about 20-30 nm. The morphology results showed that cellulose has a cavity-like structure and the green-synthesized Ag NPs were dispersed throughout the cellulose polymer matrix. In comparison to cellulose/Ag NPs and Ag nanoparticles, cellulose/Ag NPs demonstrated excellent antibacterial activity, Proteus mirabilis (MTCC 1771) possessed a maximum inhibition zone of 18.81.5 mm at 2.5 g/mL, and Staphylococcus aureus (MTTC 3615) had a minimum inhibition zone of 11.30.5 mm at 0.5 g/mL. Furthermore, cellulose/Ag NPs also exhibited a significant radical scavenging property against the DDPH free radical, and there was a higher degradation efficiency compared to pure Ag NPs against Rhodamine B as 97.38% removal was achieved. Notably, cellulose/Ag NPs remarkably promoted the transfer and separation of photogenerated electron-hole (e-/h+) pairs, thereby offering prospective application of the photodegradation efficiency for Rhodamine B (RhB) as well as antibacterial applications. With the findings from this study, we could develop efficient and environmentally friendly cellulose/Ag nanoparticles using low-cost, environmentally friendly materials, making them suitable for industrial and technological applications.

Preparation and characterization of activated carbon obtained from Melaleuca cajuputi leaves

This study aimed to prepare and characterize activated carbon derived from M. cajuputi leaves. The preparation process consisted of physical and chemical activation with phosphoric acid (H3PO4) using various impregnation ratios, which were carbonized in nitrogen under thermal treatment at 500 °C for 45 min. The surface area, pore volume, pore size, and surface morphology were determined using Brunauer-Emmett-Teller and Field Emission Scanning Microscopy to describe the characteristics of the prepared activated carbon; others are percentage yield, moisture content, and pH. The results indicated that the optimum pore volume, micropore, and mesopores were 0.099 m3/g, 66.01 m2/g, and 114 m2/g, respectively, and the BET surface area was 128 m2/g degassed at 300 °C. Field Emission Scanning Microscopy images reveal clear pores, cracks, porous structures, and a diverse surface morphology. The percentage yield was in the range of 33 to 43.7 %, and the pH was maintained in the range of 3 to 5. The ash contents of the prepared carbons in this study initially rose from 1.9 to 3.1 % due to an increase in phosphoric acid. These results conclude that M. cajuputi leaves are an effective precursor to produce the cheapest and most economical activated carbon (adsorbent) that could serve as a substitute for commercial activated carbon. Furthermore, M. cajuputi AC is effective and often considered harmless and nontoxic, which is beneficial when used as an adsorbent for the removal of contaminants from the environment. It is less harmful to human health and the environment compared to chemically hazardous, manufactured adsorbents.

Non-enzyme picomolar sensing of acephate by modified glassy carbon electrode using bimetallic Zn-Cu metal-organic framework

Organophosphate pesticides are used ubiquitously in agriculture; however, their excessive use can cause problems for human health and the environment. Herein, a non-enzymatic electrochemical sensor has been designed and developed for sensing acephate, which is based on modifying a glassy carbon electrode (GCE) with a zinc-copper metal–organic framework (Zn-Cu MOF) as a sensing material and activated charcoal (AC) as an additive for enhancing conductivity and charge transfer rate. Bimetallic Zn-Cu MOF was synthesized using the one-pot solvothermal method and was characterized by different analytical techniques, viz., Field Emission scanning microscope (FE-SEM), High-Resolution Transmission Electron Microscopy (HR-TEM), X-ray Photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), Raman spectroscopy, and Fourier-transform infrared (FTIR) spectroscopy. The electro-catalytic behavior of the modified GCE was studied using Cyclic voltammetry (CV), Electrochemical impedance spectroscopy (EIS), and Differential pulse voltammetry (DPV), which shows better performance as compared to the bare electrode. The modified GCE demonstrates excellent electro-catalytic activity towards acephate molecules, which may be attributed to the synergistic effect of metal ions, high porosity, enhanced active sites, superior conductivity, higher specific surface area, and faster electron transfer rate. After optimization of parameters such as electrolyte pH and volume of coating on GCE, the Zn-Cu MOF/AC/GCE-based electrochemical sensor provides excellent performance in terms of a more comprehensive linear range from 0.1 to 10 nM, the limit of detection (LOD) of 3.3 pM (S/N = 3), excellent selectivity and reproducibility. The extract of vegetable samples spiked with acephate gave satisfactory recovery results in 95.2–103% for tomato juice and 97–107% for cucumber juice.

(Digital Presentation) Hydrogen Peroxide Assisted Fluorescent Carbon Nanoparticles from Teak Leaves

H2O2supported carbon nanoparticles were synthesized through hydrothermal treatment. The Fluorescent Carbon Nanoparticles (FCNs) could be easily functionalized with H2O2 and showed blue emission fluorescence with higher stability in aqueous solution. The FCNs were characterized using absorption spectroscopy, Fluorescence spectroscopy, Fourier-transformed Infrared spectroscopy, Field Emission Scanning Microscopy, and Transmission Electron Microscopy. The synthesized FCNs were subsequently applied in dye sensitized solar cells to enhance the efficiency of the solar cells. The essential photovoltaic parameters, such as open circuit voltage (VOC), short circuit current density (ISC), fill factor (FF), and the overall conversion efficiency (η), were evaluated. The solar-to-electric efficiency of the fabricated dye sensitized solar cell was 0.10%. Furthermore, electrochemical impedance spectroscopy (EIS) was performed to elucidate the charge transfer and transport processes that occur in the fabricated DSSC.

Formulation and Evaluation of New Sustained Release Floating Microspheres of Cilnidipine by Solvent-Diffusion Evaporation Technique

The purpose of the present investigation was to develop a gastro-retentive cilnidipine loaded floating microspheres. The floating microspheres of cilnidipine were prepared by the solvent evaporation method for oral drug delivery using HPMCK4M and ethyl cellulose as polymers. The drug loaded microspheres were evaluated for particle size, drug content, entrapment efficiency and floating time. The in-vitro study was performed in pH 1.2 to determine the amount of drug released. Field emission scanning electron microscopy (SEM) was performed to check the surface morphology of microspheres. The mean particle size of the microspheres was in the range of 226.85 – 339.42µm. The drug content of the floating microspheres was more than 70% and drug entrapment efficiency of microspheres obtained between 64.64 – 83.0%. The in-vitro buoyancy was more than70%. Cumulative % of drug release obtained between 73.12 – 89.68%. Field emission scanning microscopy results showed that the prepared microspheres were smooth and spherical.The study reveals that more the particle size extended the floating time, this methods reveals that the drug content of the microspheres enhanced as the amount of polymer increased or increased in ethyl cellulose concentration also leads to increase in entrapment efficiency and particle size. Cumulative % drug release decreased as ethyl cellulose concentration increased.
 Keywords: cilnidipine, microspheres, floating drug delivery system, entrapment efficiency, cumulative drug release, ethyl cellulose, Field emission scanning electron microscopy, polymer, concentration

H2O2 scavenging and biocompatibility assessment of biosynthesized cellulose/Fe3O4 nanocomposite showed superior antioxidant properties with increasing concentration

Cellulose-based multi-component nanocomposites and biomaterials have some unique properties that give rise to construction in various fields. Recently many studies focused on green technology, which avoids toxic chemicals to make the environment sustainable. The hot-plate combustion method (HPCM) provides a green synthesis that can be used to achieve this goal. Present work deals with the synthesis of cellulose/Fe3O4 nanocomposite (1:1 ratio) via the co-precipitation method and analyzes the biocompatibility and photocatalytic activity. X-ray diffraction (XRD) pattern confirms the formation of cellulose II phase for cellulose and cubic crystalline phase of Fe3O4 particles. Fourier transform infrared (FTIR) analysis showed that the synergy of carbohydrates and proteins is responsible for the fabrication of Fe3O4 nanoparticles and confirms the formation of cellulose/Fe3O4 nanocomposite by the green method. Field emission scanning microscopy (SEM) images revealed two different shapes of cellulose/Fe3O4 nanocomposites including rods and spherical shapes of nanomaterials with particle sizes observed between 20 and 30 nm. The bandgap of cellulose/Fe3O4 nanocomposite was achieved to 2.79 eV, which depicted the best active antibacterial and photocatalyst. The cellulose/Fe3O4 nanocomposite exhibited strong antibacterial as well as antioxidant activity compared with Fe3O4 nanoparticles, towards with maximum of (17.3 ± 0.5 mm) at 2.5 µg/mL against Escherichia coli (MTCC 443) and minimum zone of inhibition of (9.6 ± 1.1 mm) on Staphylococcus aureus (MTTC 3615) at 0.5 µg/mL, respectively. The breakdown of an aqueous medium of methyl orange (MO) dye by the cellulose/Fe3O4 nanocomposite was investigated under visible light irradiation and a higher degradation efficiency of 96.25% was attained at 120 min. The synthesized cellulose/Fe3O4 nanocomposite showed a positive response for photocatalytic and antibacterial activity.

Divalent cation substitution impact on the properties of strontium aluminium hexaferrite (SrAl2Fe10O19)

The strontium aluminium hexaferrite was substituted with the divalent ions (Ba/Ca) with the chemical formula of Sr1-xMxAl2Fe10O19 (M = Ba, Ca; x = 0.1, 0.2), and all the samples were synthesized via sol-gel auto combustion method. The particles are shaped in a hexagonal structure with space group P63/mmc. The field-emission scanning microscopy revealed the platelet-like morphology of the particles. The magnetic studies disclosed the single-domain arrangement of particles and decent energy product value for all the samples (0.36–0.38 MG Oe), implying their potential application in permanent magnets. The declined value of the Dielectric constant at mega-range frequency suggests that the samples could be useful for microwave application.

Studies on the Effect of Substrate Preheating, Interlayer Dwell, and Heat Treatment on Microstructure, Residual Stress, and Mechanical Properties of IN625 Superalloy Built by Direct Metal Deposition

Abstract In this investigation, IN625 alloy samples were processed by the directed energy deposition (DED) approach under various metal deposition strategies such as substrate preheating, interlayer dwell and with combined substrate preheating, interlayer dwell, as well as postheat treatment. The processed sample’s microstructural characteristics, residual stress, microhardness, and tensile properties are assessed in comparison to the manufacturing strategies. Rapid heat dissipation caused finer microstructure near the substrate. There is a growth of columnar grain structure epitaxially in the build direction. The progressive microstructure change seen in the build direction across the cross section was due to the gradual rise of heat accumulation between subsequent layers. The interdendritic zones contained Laves phases. Laves phases have a high Nb, Mo, as well as Si content, according to the energy-dispersive spectroscope (EDS) spectrum. The field emission scanning microscopy (FESEM) microstructural morphology of the deposited samples after their postheat treatment has shown a new microstructure with the combination of equiaxed (recrystallized) and columnar dendritic structure with the reconstruction of columnar dendritic solidification microstructure into equiaxed grains. Heat treatment caused the Laves phases to dissolve in the matrix of IN625 alloy, which led to the precipitation of nanometric γ″ phases. The deposition strategies with substrate preheating significantly decreased the residual stress with moderately improved mechanical properties. The combination of substrate preheating, interlayer dwell, and postheat treatment has shown an outstanding reduction of residual stress along with a remarkable improvement in tensile strength with the retainment of an equivalent ductility compared with other strategies.

Facile route for synthesizing WS2/W2C nano hollow flowers and their application for hydrogen evolution reaction

Recently, catalysts based on tungsten disulfide nanoflowers (WS2 NFs) and tungsten carbide (W2C) materials have been intensively investigated for hydrogen evolution reaction (HER). In this study, a facile and scalable route was utilized to synthesize a nano hollow flowers catalyst based on heterostructure of WS2 and W2C (WS2/W2C NHFs). Besides that, other structures of tungsten compounds including WS2–WO3 flower particles (FPs) and pure WS2 NFs were also prepared by the similar route with slight modification, to compare the differences in their structures and HER activities. Materials properties were comprehensively studied via X-ray diffraction analysis, field emission scanning microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy. Then, the HER catalytic activities of synthesized materials were also carefully studied. The results indicate that WS2/W2C NHFs exhibits the HER activities much better than that of prepared WS2–WO3 FPs and pure WS2 NFs. The HER performance of WS2/W2C NHFs exhibits a low Tafel slope of about 61 mV.dec−1, an overpotential of − 280 mV at − 10 mA.cm-2, high double-layer capacitance (11.9 mF cm-2) and the superstability in acid media. This improvement is attributed to the synergistic effect of the WS2 and W2C heterostructure as well as the special structure of WS2/W2C NHFs catalyst.

CuxO@Cu mesh electrode with {1 1 1} facet for efficient photo-electro-Fenton reaction and low voltage robustness

In this work, CuxO nanoarrays containing Cu2O and CuO with different morphologies were synthesized on the surface of copper mesh by anodic oxidation method, and the prepared CuxO@Cu mesh electrodes were confirmed by X-ray diffraction (XRD), field emission scanning microscope (SEM), and X-ray photoelectron spectroscopy (XPS). Cyclic voltammetry (CV) and photocurrent were used to characterize the composite electrode. The photo-electro-Fenton (PEF) catalytic system constructed with the prepared CuxO@Cu electrode anode has excellent H2O2 utilization efficiency and pollutant degradation rate. Degradation efficiency of methylene blue (MB) by electro-Fenton (EF), photo-Fenton (PF) and photo-electro-Fenton (PEF) processes were investigated, which was in order: PEF > PF > EF. The effects of applied voltage, current density, pH and H2O2 concentration on MB degradation were investigated. MB could be quickly degraded at CuxO@Cu electrode during heterogeneous photo-electro-Fenton process with a first-order kinetic constant of 3.61 h−1 under 300 W simulated sunlight irradiation at 0.6 V, pH 7.0, 4.9 mmol H2O2. The CuxO@Cu electrode anode was stable and could be reused without catalytic reduction, and also had good degradation efficiency on other organic compounds (p-nitrophenol, tetracycline, norfloxacin), having potential application value in wastewater treatment.

Molecular Interaction of Functionalized Nanoplastics with Human Hemoglobin.

Humans are exposed to excessive nanoplastics (NPs) which have ample affinity for globular proteins. We investigated the interaction of functionalized polystyrene nanoplastics (plain: PS, carboxy: PS-COOH, and amine: PS-NH2) with human hemoglobin (Hb) utilizing multi-spectroscopic and docking approaches to acquire insights into molecular aspects of binding mechanism, which will be helpful in assessing the toxicokinetics or toxicodynamics of nanoplastics NPs. Hypsochromicity and hypochromicity were observed invariably in all the spectra (steady-state fluorescence emission, synchronous and three-dimensional) for all complexes, among which PS-NH2 binds effectively and changes the Hb's conformation by enhancing hydrophobicity around aromatic residues, notably tryptophan. All the NPs bind with the hydrophobic pocket of B-chain in Hb, where PS and PS-NH2 bind via hydrophobic force while PS-COOH binds via hydrogen bonding (predominantly) and van der Waals force, consistent validated with docking results. The minimal shift in absorbance peak also indicates enhanced hydrophobicity by PS-NH2 with larger aggregation as demonstrated in resonance light scattering. The amide band's shift, secondary structural analysis, and presence of characteristic functional group peaks in complexes in Infra-Red spectra confirm the structural changes in the protein. As seen in field emission scanning microscopy images, NPs penetrate the surface of proteins. These findings conclude that polystyrene NPs interact with Hb, causing structural alterations that may affect functional characteristics as well, with the greatest effect being in the order: PS-NH2>PS-COOH>PS.