Energy Dispersive X-ray Spectroscopy Research Articles

L-Cysteine/Silver Nitrate/Iodate Anions System: Peculiarities of Supramolecular Gel Formation with and Without Visible-Light Exposure

In this study, novel anion photo-responsive supramolecular hydrogels based on cysteine–silver sol (CSS) and iodate anions (IO3−) were prepared. The peculiarities of the self-assembly process of gel formation in the dark and under visible-light exposure were studied using a complex of modern physico-chemical methods of analysis, including viscosimetry, UV spectroscopy, dynamic light scattering, electrophoretic light scattering, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. In the dark phase, the formation of weak snot-like gels takes place in a quite narrow IO3− ion concentration range. The visible-light exposure of these gels leads to an increase in their viscosity and dramatic change in their color. The morphology of gels alters after light irradiation that is reflected in the formation of a huge number of spherical/elliptical particles and the thickening of the fibers of the gel network. The interaction of CSS with IO3− anions has features of a redox process, which leads to the formation of silver iodide/silver oxide nanoparticles inside and on the surface of CSS particles. CSS possesses selectivity only to IO3− anions compared to many other inorganic ions relevant for humans and the environment. Thus, the CSS/IO3− system is non-trivial and can be considered as a novel low-molecular-weight gelator with photosensitive properties, as another way to produce silver iodide nanoparticles, and as a new approach for IO3− ion detection.

Microstructural and Surface Texture Evaluation of Orthodontic Microimplants Covered with Bioactive Layers Enriched with Silver Nanoparticles

Bacterial infections are a common cause of clinical complications associated with the use of orthodontic microimplants. Biofilm formation on their surfaces and subsequent infection of peri-implant tissues can result in either exfoliation or surgical removal of these medical devices. In order to improve the properties of microimplants, hybrid coatings enriched with silver nanoparticles, calcium, and phosphorus were investigated. The present study aimed to assess the microstructure of commercially available microimplants composed of a medical TiAlV (Ti6Al4V) alloy covered with organic–inorganic layers obtained by the sol–gel method using the dip-coating technique. The microstructures and elemental surface compositions of the sterile, etched, and layer-modified microimplants were characterized by scanning electron microscopy with X-ray energy-dispersive spectroscopy (SEM-EDS). Elements such as silver (Ag), calcium (Ca), phosphorus (P), silicon (Si), oxygen (O), and carbon (C) were detected on the microimplant’s surface layer. The SEM observations revealed that control microimplants (unetched) had smooth surfaces with only manufacturing-related embossing, while etching in hydrofluoric acid increased the surface roughness and introduced fluoride onto the microimplants. Layers with only silver nanoparticles reduced the roughness of the implant surface, and no extrusion was observed, while increased roughness and emerging porosity were observed when the layers were enriched with calcium and phosphorus. The highest roughness was observed in the microimplants etched with AgNPs and CaP, while the AgNPs-only layer showed a reduction in the roughness average parameter due to lower porosity. Enhancing the effectiveness of microimplants can be achieved by applying selective surface treatments to different parts. By keeping the outer tissue contact area smooth while making the bone contact area rough to promote stronger integration with bone tissue, the overall performance of the implants can be significantly improved.

Optical, structural, and vibrational properties of In2S3 thin films by Sputtering-RF for applications in optoelectronics devices.

Abstract Experimental results on the crystalline orientation properties, energy band gap, and Raman vibrational modes of Indium Sulfide (In2S3) thin films grown by Sputtering in Radio Frequency mode are presented. The In2S3 thin films were grown at 25, 200, and 300°C; thereafter the samples were thermally annealed in air for 30 min at 450°C, in order to improve their crystalline and physical properties. Energy dispersive X-ray spectroscopy results showed that the β-In2S3 crystallographic phase became predominant as the substrate temperature increased. For the optical transmittance spectra, it was observed that the deposited In2S3 thin films at 300°C and with thermal annealing showed an increase in their band gap energy of nearly 60 meV. The direct energy band gap of In2S3 films varied in the range of 2.76–2.82 eV. The scanning electron microcopy image and elemental analysis shows a better morphology, and an increase in O and Sn when the In2S3 samples were subjected to thermal annealed and the substrate temperature increased, respectively. Photoluminescence spectra were obtained at room temperature and showed two emission bands around 1.75 (709 nm) and 2.35 eV (527 nm), one related to interstitial indium donor sites (Ini) and oxygen acceptor vacancies (OVs), and the second to an emission band corresponding to the transition sulfur donor-indium acceptor. As the substrate temperature increased and thermal annealing of In2S3 was performed, the 1.75 eV emission bands increased in intensity with respect to the 2.35 eV band. From the Raman measurements, it was observed that the vibrational peaks were better defined as the substrate temperature increased and In2S3 underwent thermal annealing. In addition, to study the spinel-like defect structure, the peaks corresponding to the five main vibrational modes of In2S3 were identified as the Alg mode, Eg mode, and three modes of the F2g.

Impact of Aerogel Modification for Fe‑N‑C Activity and Stability towards Oxygen Reduction Reaction in Phosphoric Acid Electrolyte.

Resorcinol-formaldehyde based carbon aerogel has been tailored to meet the requirements as a Fe‑N‑C carbon support, aiming to provide sufficient, inexpensive cathode catalyst for high-temperature polymer electrolyte membrane fuel cells (HT‑PEMFCs). Therefore, different treatments of the aerogel are explored for optimal pore structure and incorporation of surface functionalities, which are crucial for Fe‑N‑C synthesis and electrochemical performance. Fe‑N‑Cs of differently modified aerogel are investigated in phosphoric acid electrolyte. The results show that HNO3 treatment for 5 h yields the Fe‑N‑C with highest mass activity and selectivity, attributed to the highest amount of nitrogen functionalities revealed by energy dispersive X-ray spectroscopy (XPS) and proper Fe‑N-x site formation. HNO3 oxidation for 2h leads to Fe‑N‑C with slightly lower oxygen reduction reaction (ORR) activity and selectivity. In contrast, the Fe‑N‑C synthesized from CA with H3PO4 treatment shows negligible ORR activity. The feasibility of one-step activation and carbonization treatment with K2CO3 and, for the first time, with K2CO3 and melamine is proven as the obtained Fe‑N‑Cs exhibit promising ORR activity. The results are compared with the commercial Fe‑N‑C PMF-014401. This study contributes to the advancement of cost-efficient HT‑PEMFCs by optimizing Fe‑N‑C catalyst properties.

Performance Assessment of Eco-Friendly Asphalt Binders Using Natural Asphalt and Waste Engine Oil

The depletion of petroleum reserves and increasing environmental concerns have driven the development of eco-friendly asphalt binders. This research investigates the performance of natural asphalt (NA) modified with waste engine oil (WEO) as a sustainable alternative to conventional petroleum asphalt (PA). The study examines NA modified with 10%, 20%, and 30% WEO by the weight of asphalt to identify an optimal blend ratio that enhances the binder’s flexibility and workability while maintaining high-temperature stability. Comprehensive testing was conducted, including penetration, softening point, viscosity, ductility, multiple stress creep recovery (MSCR), linear amplitude sweep (LAS), energy-dispersive X-ray spectroscopy (EDX), Fourier transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM). The results reveal that WEO effectively softens NA, improves ductility, and enhances workability, with the 20% WEO blend achieving the best balance of physical and rheological properties. Chemical analysis indicates that WEO increases carbon content and reduces sulfur and impurities, aligning NA’s composition closer to PA. However, excessive WEO (30%) compromises thermal stability and deformation resistance. The findings underscore the potential of WEO-modified NA for sustainable pavement applications, with 20% WEO identified as the optimal content to achieve performance comparable to conventional petroleum asphalt while promoting environmental sustainability.

Lead-free dielectric thin films: Synthesis of Ag(Nb1−xTax)O3 via reactive dc magnetron sputtering

Growing environmental concerns have driven the switch from lead-containing dielectric perovskite ceramics to lead-free alternatives such as silver niobate tantalate [Ag(Nb1−xTax)O3], where tantalum (Ta) substitution for niobium (Nb) enhances energy-storage density. Thin film deposition presents a promising way for fabricating these materials for use in capacitors. In this study, Ag(Nb1−xTax)O3 (0 ≤ x ≤ 0.5) thin films are synthesized via combinatorial reactive dc magnetron sputtering from metallic targets. The chemical and phase compositions of the films are comprehensively analyzed using scanning electron microscopy coupled with energy dispersive x-ray spectroscopy, elastic recoil detection analysis, Rutherford backscattering spectrometry, x-ray diffraction, Raman spectroscopy, and x-ray photoelectron spectroscopy. The findings demonstrate that reactive dc magnetron sputtering is a feasible technique for producing complex perovskite oxide thin films with customized chemical composition and microstructure. By enhancing the understanding of the Ag(Nb1−xTax)O3 material system, this study aims to contribute to the development of environmentally benign high-performance dielectrics that could replace lead-based ceramics in energy-storage applications.

Phytoextract-assisted synthesis of Fe2O3/MgO nanocomposites for efficient photocatalytic degradation of gentian violet

Organic-based pollutants are extensively released from various industries and they potentially harm the environment and human health. Photocatalysis is regarded as one of the most promising techniques for removal of organic contaminants from wastewater. Therefore, in this study, iron oxide-based nanocomposites were synthesized by an emerging green and sustainable method using Ethiopian endemic plant extract, Echinops kebericho M. as a capping and stabilizing agent. The phytoextract-assisted synthesized nanoparticles (NPs) α-Fe2O3 and nanocomposites (NCs) α-Fe2O3/MgO calcinated at a temperature of 400°C were characterized and used for their photocatalytic activities toward gentian violet (GV) dye degradation using ultraviolet–visible spectroscopy (UV-vis) at optimized catalyst dose, initial GV concentration, pH, and time conditions. The X-ray diffraction (XRD) analysis result revealed that the mean crystal size of α-Fe2O3 and α-Fe2O3/MgO is 11.2 and 15.4 nm, respectively. Characterization results of scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and X-ray photoelectron spectroscopy (XPS) clearly showed the successful deposition of MgO on α-Fe2O3. The maximum degradation of GV, 96.2%, was observed by using α-Fe2O3/MgO after 60 min under visible light irradiation. Thus, synthesized NCs were shown to have better GV degradation efficiency in a shorter time as compared to the previously reported nanomaterials. The results revealed photocatalytic degradation using endemic plant extract-assisted synthesized NCs, α-Fe2O3/MgO, is considered a greener, simple, and more efficient method for the removal of organic dyes.

Structure and improved corrosion properties of MAO coating on Mg-5Gd-1Zn-0.4Zr formed under various current densities

To investigate the structure and corrosion properties of micro-arc oxidation (MAO) coating on Mg-5Gd-1Zn-0.4Zr (GZ51K) alloys for biomedical application, the alloy was MAO-treated using silicate electrolyte system under current density of 400, 600 and 800 mA/cm2 respectively. The microstructure, surface analysis and corrosion resistance of samples were evaluated by scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, potentiodynamic polarisation, electrochemical impedance spectroscopy in SBF solution. The results indicate that the main phases of the MAO coatings were MgO, Mg2SiO4 and MgF2. With the increase of MAO current density, the thickness of the MAO coating decreased from 16.5 to 10.4 μm. When MAO current density is 400 mA/cm2, the specimen shows the best corrosion resistance with a four-order-of-magnitude decrease on Icorr ((1.95 ± 0.01) × 10−10 A/cm2), a four-order-of-magnitude increase on RP((7.67 ± 0.02) × 107 Ω cm2). Even though the thickness of the MAO coatings obtained with 600 and 800 mA/cm2 are very close, the corrosion resistance of the coating prepared under 800 mA/cm2 is better than that under 600 mA/cm2. Generally, MAO treatment can greatly slow down corrosion rate of the GZ51K alloy and keep uniform corrosion mode which is desirable for biodegradable implant applications.

Characteristics and main controlling factors for the development of shale micro pore-fracture in Tiemulike Formation, Yining Basin

Research on the type, size, structure, and other characteristics of shale micro pore-fracture and their genesis is one of the core index for Shale gas study. Based on systematically collected shale samples from outcrop profiles and well cores, the experiments of thin-section observation, scanning electron microscopy, energy-dispersive X-ray spectroscopy, whole-rock analysis, rock–eval pyrolysis and basin simulation analysis were performed to study the micro pore-fracture characteristics and its main controlling factors for the development of shale pores in Tiemulike Formation in Yining Basin. The results show that four types of micro pore-fractures were identified: organic hydrocarbon-generating micro pores, granular dissolved micro pores, intergranular micro pores, and micro-fracture. The development of micro pores in shales is influenced by the internal material composition of the shale reservoir and external temperature conditions. The high organic carbon content with a high degree of thermal evolution led to the development of numerous micro pores, and the main micro pores were produced by shrinking the hydrocarbon generation volume due to the thermal evolution of organic matter. The development of micro-fractures was found to be favoured by the high content of brittle minerals and overpressure in the formation.

Tribological Properties and Wear Mechanism of Phenolic Resin Incorporated Rare Earth Oxides

Different proportions of rare earth oxides, specifically cerium oxide and yttrium oxide, were incorporated into phenolic resin-based friction materials to mitigate the thermal degradation of resin-based friction materials. The effects of these additives on the mechanical properties and tribological performance of resin-based friction materials were thoroughly investigated, and the microstructure and phase composition were characterized via field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). The addition of rare earth oxides favorably improved the density, hardness, compression strength, and shear strength of the composites, with rare earth yttrium oxide dominating the hardness of the composites and cerium oxide dominating the compression strength of the composites, but changes in the ratio of the two had a small effect on their density, shear strength, and impact strength. Among them, the highest density, hardness, compressive strength, and shear strength of the modified sample could reach 2.310 g/cm3, 118 HRL, 187.5 MPa, and 43.5 MPa, respectively, and their properties were improved by 7.7%, 14.6%, 19%, and 51%, respectively, compared with the unmodified sample Y0. The incorporation of rare earth oxides was not conducive to the improvement of the fade friction coefficient and recovery friction coefficient of the composites, but was beneficial to the stabilization of the recovery friction coefficient of the composites and the reduction in their average wear rate, with the yttrium oxide-dominated matched samples focusing on high-temperature stability, and cerium oxide-dominated matched samples focusing on the antioxidant reduction property. The homogeneous dispersion and synergistic enhancement effect of the rare earth oxides in the matrix materials enhanced the structural integrity and densification of the matrix materials and improved the interfacial strength and surface wear resistance of the composites. The worn surface of the unmodified sample Y0 was mainly abrasive and thermal fatigue wear, the worn surface of the yttrium oxide-dominated matched samples Y1 and Y2 was mainly abrasive wear, and the worn surface of the cerium oxide-dominated matched samples Y3 and Y4 was mainly adhesive and thermal fatigue wear.

Synthesis of Cu doped Ba(OH)2 thin film by SILAR method for supercapacitor electrode application

Abstract An economically suitable successive ionic layer adsorption and reaction (SILAR) method has been used to deposit 0.25, 0.50 and 0.75 wt% copper doped barium hydroxide on stainless steel (SS) substrate. X-ray diffraction analysis shows the orthorhombic crystal structure of Cu doped Ba(OH)2 electrode. FTIR analysis reveals the chemical bonds present in the sample. The energy-dispersive x-ray spectroscopy (EDAX) and x-ray photo electron spectroscopy (XPS) measurements have been performed to confirm Cu doping into Ba(OH)2. The electrochemical properties of Cu doped Ba(OH)2 electrode have been analysed by cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) techniques. The 0.50 wt% Cu doped barium hydroxide electrode exhibits the highest specific capacitance (Csp) of 356.12 F g−1 (59.55 mF cm−2) at 1 mV s−1 scan rate in 1 M Na2SO4 electrolyte solution. This electrode also shows ~ 85% capacitance retention up to 8000 cycles. A symmetric device has also been fabricated by using two electrodes. This device shows energy and power densities of 1.13 Wh Kg-1 and 279.7 W Kg-1 respectively. This cyclic retention and capacitive behaviour of Cu-doped Ba(OH)2 shows its utility as an energy storage material in the near future.

Failure Analysis of Al 6082 Joints Processed by FSW and SFSW

This paper presents a failure analysis of Al 6082 joints processed by Friction Stir Welding (FSW) and Self-Reacting Friction Stir Welding (SFSW) techniques. Aluminium alloy Al 6082 is commonly used in structural and automotive applications due to its excellent strength, corrosion resistance, and weldability. The study focuses on investigating the failures encountered in FSW and SFSW joints of Al 6082. Macroscopic and microscopic examinations are conducted to analyse the root causes of these failures. Macroscopic observations include visual inspection, dimensional measurements, and identification of fracture locations. Microscopic investigations utilize techniques such as optical microscopy, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS) to examine the microstructure, fracture surfaces, and elemental composition of the failed joints. The results of this failure analysis contribute to the understanding of Al 6082 joining processes using FSW and SFSW methods. By identifying the failure mechanisms and proposing preventive measures, this research aids in improving the quality and performance of Al 6082 joints, thereby ensuring the integrity and reliability of joined structures in industries that rely on aluminium alloys for critical applications.

Magnetically retrievable carbon-wrapped CNT/Ni nanospheres as efficient catalysts for nitroaromatic reduction.

We present a facile strategy for synthesizing magnetically retrievable carbon-wrapped CNT/Ni nanospheres (C-wrapped CNT/Ni) that enhance the catalytic performance of metals for environmental pollutant reduction. Structural and compositional analyses using X-ray diffraction (XRD), Raman spectroscopy, energy-dispersive X-ray spectroscopy (EDS), and field emission scanning electron microscopy (FESEM) confirmed the phase purity, morphology, and structure of the C-wrapped CNT/Ni. XRD, Raman, and EDS data validate the formation of the nanospheres, while FESEM images reveal uniform Ni nanospheres wrapped with a carbon layer through interconnected, evenly dispersed CNTs. Initially, Ni nanoparticles were anchored onto multiwalled carbon nanotubes to form magnetic CNT/Ni nanospheres, which were then coated with a carbon layer to prevent aggregation, improve Ni particle stability, and introduce additional surface functionalities. The catalytic efficacy of C-wrapped CNT/Ni was assessed through the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP). The reaction rate constant (k app = 0.6167 min-1) with C-wrapped CNT/Ni is approximately six times higher than that with bare Ni nanospheres (k app = 0.1056 min-1). This enhanced catalytic activity is attributed to the synergistic effect between the spherical Ni core and the wrapped carbon layer, mediated by the interconnected CNT, which promotes efficient hydride formation. Additionally, C-wrapped CNT/Ni demonstrates exceptional reusability in the 4-NP reduction process. The integration of these features within a single framework suggests its significant potential for diverse engineering and environmental applications.

Failure Analysis of AA 7075 Joints Processed by FSW and SFSW

This paper presents a failure analysis of AA 7075 Aluminium 7075 joints processed by Friction Stir Welding (FSW) and Submerged Friction Stir Welding (SFSW) techniques. AA 7075 is a high-strength aluminium alloy commonly used in aerospace, automotive, and other industries due to its excellent mechanical properties. Understanding the failure mechanisms in these joining processes is essential for ensuring the structural integrity and reliability of AA 7075 joints. The study investigates the failures encountered in FSW and SFSW joints of AA 7075. Macroscopic and microscopic examinations are conducted to analyse the root causes of these failures. Macroscopic observations include visual inspection, dimensional measurements, and identification of fracture locations. Microscopic investigations utilize techniques scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) to examine the microstructure, fracture surfaces, and elemental composition of the failed joints. Based on the failure analysis findings, recommendations are provided to enhance the quality and reliability of AA 7075 joints processed by FSW and SFSW. The results of this failure analysis contribute to the understanding of AA 7075 joining processes using FSW and SFSW methods. By identifying the failure mechanisms and proposing preventive measures, this research aids in improving the quality and performance of AA 7075 joints, thereby ensuring the integrity and reliability of joined structures in industries that rely on aluminium alloys for critical applications.

Nitride Zeolites from Ammonothermal Synthesis.

Oxide zeolites are synthesized from aqueous solutions in an established way employing hydrothermal synthesis. Transferring this approach to nitride zeolites requires a solvent providing nitrogen for which ammonia has proven to be particularly suitable. We present the successful ammonothermal synthesis of the (oxo)nitridosilicate compounds Ce3[Si6N11], Li2RE4[Si4N8]O3 (RE = La, Ce) and K1.25Ce7.75[Si11N21O2]O0.75. Within this procedure, the usage of supercritical ammonia as a solvent as well as the utilization of the mineralizers NaN3, Li3N and KN3, respectively, allowed the targeted synthesis of large single crystals. Formation of these (oxo)nitridosilicates depend mainly on the employed mineralizer despite their similar degree of condensation. The three compounds were structurally characterized using X-ray diffraction and their crystal structures contain a wide range of different ring sizes within their tetrahedra networks. The zeolite(-like) crystal structures are elucidated and compared to known nitridosilicate representatives of the respective structure types. Their elemental composition was investigated using energy-dispersive X-ray (EDX) spectroscopy and incorporation of the O rather than N-H functionality was confirmed by Fourier-Transform infrared (FTIR) spectroscopy as well as by charge distribution (CHARDI) and bond valence sum (BVS) calculations. The presented examples demonstrate that ammonothermal synthesis provides a one-step access from elemental starting materials towards nitride zeolites.

Phycogenic nanoparticles efficiently catalyse pesticide degradation through a novel metabolic pathway utilizing solar light

Cypermethrin (Cy) is a widely used insecticide, leading to significant environmental contamination in homes and agricultural areas. Effective methods to minimize or eliminate insecticidal residues are essential. Seaweeds, traditionally used in agriculture as soil conditioners, offer a promising solution for remediating pesticide-contaminated soils through biogenic nanoparticle synthesis. In this study, we synthesized biogenic silver nanoparticles (UL-AgNPs) from the green seaweed Ulva lactuca Lin (Ulvaceae) to degrade Cypermethrin. The UL-AgNPs were characterized using UV-Visible spectroscopy, Scanning Electron Microscopy equipped with Energy dispersive X-ray spectroscopy, Fourier Transform Infra-red spectroscopy, X-ray diffraction, Dynamic light scattering and zeta potential analysis, confirming their presence, size (81.29 nm), structure and stability. Response surface methodology (RSM) was used to assess the catalytic concentration of photocatalyst for degradation of pesticide including variables, Cy concentration and destined exposure time duration. The degradation efficiency of UL-AgNPs was evaluated, with the highest degradation (91.2%) achieved at pH 7 after 12 hours using 16.6 mg L-1 of UL-AgNPs, following pseudo-first order kinetics with a rate of 2.7 hour-1. GC-MS and UV-Visible spectroscopy revealed a novel degradation pathway, where Cypermethrin was broken down into compounds like Tetradecane, Dodecane, and Tetracosanoic acid through ester cleavage and benzene ring breakdown. The study also demonstrated the reusability of UL-AgNPs for four cycles, highlighting their potential for sustainable environmental management by reducing the long-term hazards of Cypermethrin.

Application of green synthetic iron oxide nanocatalyst in biohydrogen production from domestic wastewater.

Hydrogen (H2) is considered to be an energy carrier with high yields in future. Using green nanoparticles as the catalyst to produce H2 from organic wastes is an environmentally friendly and cost-effective approach. This study specifically addresses H2 production biologically from domestic wastewater using dark fermentation process with green nanoparticles in anaerobic condition. In this investigation, acid, alkaline, and heat pre-treated wastewater were utilized as the feedstock and identified that the alkaline pre-treated wastewater was an efficient feedstock for H2 production. The reaction conditions such as pH, time, and nanocatalyst dosage were optimized for the enhancement of H2 production. In addition, the green iron oxide nanoparticles (Fe3O4-NPs) were prepared by sustainable way using Murraya koenigii (curry leaves) with FeSO4 and characterized it using Fourier-transform infrared spectroscopy (FT-IR), ultraviolet-visible spectrophotometer (UV-vis), power X-ray diffraction (pXRD), and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDX), further tested for their 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging performance via in vitro antioxidant activities. This study demonstrates that a maximum production of bio-H2 was obtained (72.8mL/L) with 20mg of nanocatalyst load at alkaline condition (pH 9). The correlation coefficient value was highly significant for biohydrogen production with increasing pH (r = 0.9026) and catalyst dosage (r = 0.9962). The characterization studies confirmed the existence of iron oxide nanoparticles in the green synthesized nanoparticles. The in vitro antioxidant assay showed that Fe3O4-NPs effectively reduces the DPPH radical by significantly releasing H-atoms, thereby confirming that the plant extract functions as reducing/oxidizing agents. The high yield under the dark fermentation method has clearly been attributed to the enhancement in bio-H2 production by using the green Fe3O4-NPs based on M. koenigii.

Enhancement in Corrosion Resistance of Low-Carbon Steel via Surface Modification

This research investigated the corrosion resistance of surface layers on low-carbon steel exposed to a chloride environment at room temperature. This study systematically evaluated the effects of varying pack compositions, coating temperatures, and application durations on the characteristics of the deposited coatings. The potentiodynamic polarization corrosion test was employed to assess the wet corrosion behavior of the specimens. Elemental compositions and microstructural features were analyzed using energy-dispersive X-ray spectroscopy (EDX) in conjunction with scanning electron microscopy (SEM), providing insights into phase distribution. The chromizing, titanizing, and chromotitanizing treatments were conducted at temperatures of 900 °C, 1000 °C, and 1100 °C, respectively, with varying coating times. X-ray diffraction analysis revealed a complex arrangement of elements and compounds within the coatings, including Cr, Ti, Cr1.9Ti, FeTi, Al2O3, Cr2O3, TiO2, Cr1.36Fe0.52, and (Ti0.86)3.58. The study found that as the deposition duration increased, the coating thickness increased, comprising a thin inner layer and a substantially thicker outer layer. This layered structure resulted from the outward diffusion of Fe atoms and the inward diffusion of Cr and Ti atoms. Electrochemical analysis in a 3.5% NaCl aqueous solution indicated a marked enhancement in the corrosion resistance of the coated specimens compared to their uncoated counterparts. The potentiodynamic polarization tests confirmed that the protective coatings significantly reduced the corrosion rate, with performance influenced by both the temperature and duration of the deposition process. These findings highlighted the potential of tailored coating techniques to improve the durability and performance of low-carbon steel in corrosive environments.

Design and synthesis of PDSPTCF as an influential Brønsted-Lewis acidic catalyst for the producing benzo[a]benzo[6,7]chromeno[2,3-c]phenazines

Initially, 4,4'-(1,4-phenylene)di(sulfonic)pyridinium tetrachloroferrate (PDSPTCF) as a novel organic–inorganic hybrid salt was synthesized and identified by elemental mapping, energy-dispersive X-ray spectroscopy, inductively coupled plasma atomic emission spectrometer, Raman spectroscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy, vibrating-sample magnetometry, and thermal gravimetric (TG) techniques. Then, the catalytic performance of this hybrid salt was assessed for the producing benzo[a]benzo[6,7]chromeno[2,3-c]phenazine derivatives via one-pot multicomponent domino reaction (MDR) of benzene-1,2-diamine, 2-hydroxynaphthalene-1,4-dione and aldehydes under optimal conditions (70 °C, solvent-free, 5 mol% PDSPTCF) in short reaction times and high yields. Highly efficacy of the PDSPTCF for the production of benzo[a]pyrano[2,3-c]phenazines can be assigned to the synergistic effect of Lewis and Brønsted acids, and having two positions of each acid (i.e., FeCl4ˉ and –SO3H). In addition, this catalyst showed good reproducibility with six cycles of recycling.

Surface Modification of Anodized Titanium Surfaces with Chitosan/ε-Polylysine Coating, Aiming for an Improved Bioactivity, Biocompatibility, and Anti-Bacterial Properties for Orthopedic Applications

The increasidng demand for implants due to the aging populations highlights the necessity for applying highly functional coatings on the surface of implants. This study investigates the implications of applying a chitosan/polylysine composite coating on anodized titanium surfaces, aiming for improved biocompatibility, bioactivity, and anti-bacterial properties. Titanium substrates were anodized at 40 volts for a duration of two hours, followed by dip coating with the chitosan/polylysine composite. Fourier-transform infrared (FTIR) analysis was employed to characterize the polymer structure, while field emission scanning electron microscopy (FESEM) and energy-dispersive X-ray spectroscopy (EDS) techniques were utilized to evaluate nanotube morphology and the coating structure. Results showed that samples containing 1.5% polylysine exhibited noticeable anti-bacterial properties and cell viability above fifty percent. Subsequent immersion in simulated body fluid (SBF) for a duration of two weeks revealed the formation of apatite crystals on the coated samples, indicating that the samples are bioactive. Furthermore, polylysine contributed to enhanced resistance against degradation in phosphate-buffered saline (PBS) solution. Overall, the chitosan/polylysine composite coating exhibited promising mechanical and biomedical characteristics, suggesting its potential for applications in orthopedic implants.