X-ray Transmission Research Articles

Microscale chemical imaging to characterize and quantify corrosion processes at the metal-electrolyte interface

AbstractWe introduce an experimental setup to chemically image corrosion processes at metal-electrolyte interfaces under stagnant, confined conditions—relevant in a wide range of situations. The setup is based on a glass capillary, in which precipitation of corrosion products in the interfacial aqueous phase can be monitored over time with optical microscopy, and chemically and structurally characterized with microscopic synchrotron-based techniques (X-ray fluorescence, X-ray diffraction, and X-ray absorption spectroscopy). Moreover, quantification of precipitates through X-ray transmission measurements provides in-situ corrosion rates. We illustrate this setup for iron corrosion in a pH 8 electrolyte, revealing the critical role of O2 and iron diffusion in governing the precipitation of ferrihydrite and its transformation to goethite. Corrosion and coupled reactive transport processes can thus be monitored and fundamentally investigated at the metal-electrolyte interface, with micrometer-scale resolution. This capillary setup has potential applications for in-situ corrosion studies of various metals and environments.

Metal–Organic Framework-Derived CeO2/Gold Nanospheres in a Highly Sensitive Electrochemical Sensor for Uric Acid Quantification in Milk

In this work, CeBTC (a cerium(III) 1,3,5-benzene-tricarboxylate), was used as a precursor for obtaining CeO2 nanoparticles (nanoceria) with better sensor performances than CeO2 nanoparticles synthesized by the solvothermal method. Metal–organic framework-derived nanoceria (MOFdNC) were functionalized with spheric gold nanoparticles (AuNPs) to further improve non-enzymatic electrode material for highly sensitive detection of prominent biocompound uric acid (UA) at this modified carbon paste electrode (MOFdNC/AuNPs&CPE). X-ray powder diffraction (XRPD) and transmission electron microscopy (TEM) analysis were used for morphological structure characterization of the obtained nanostructures. Cyclic voltammetry and electrochemical impedance spectroscopy, both in an [Fe(CN)6]3−/4− redox system and uric acid standard solutions, were used for the characterization of material electrocatalytic performances, the selection of optimal electrode modifier, and the estimation of nature and kinetic parameters of the electrode process. Square-wave voltammetry (SWV) was chosen, and the optimal parameters of technique and experimental conditions were established for determining uric acid over MOFdNC/AuNPs&CPE. Together with the development of the sensor, the detection procedure was optimized with the following analytical parameters: linear operating ranges of 0.05 to 1 µM and 1 to 50 µM and a detection limit of 0.011 µM, with outstanding repeatability, reproducibility, and stability of the sensor surface. Anti-interference experiments yielded a stable and nearly unchanged current response with negligible or no change in peak potential. After minor sample pretreatment, the proposed electrode was successfully applied for the quantification of UA in milk.

Insights into the effect of various supports on hydrothermal liquefaction of food waste over iron-oxide nano-catalysts

This work investigates the effect of supported iron-oxide nano-catalysts for hydrothermal conversion of food waste. The studied supports were Vulcan carbon (VC), CeO2, ZSM-5 and amorphous SiO2-Al2O3. Catalytic hydrothermal liquefaction experiments were carried out in a batch reactor at 16 MPa and 300 °C maintained for 1 h. Different fractions of Fe(0), Fe2+ and Fe3+ alter its tendency toward deoxygenation, hydrogenations and condensation reactions, which influence the bio-crude yield, elemental compositions, and energy recoveries. The fresh and spent catalysts were characterized using X-ray photoelectron spectroscopy, physisorption analysis, thermogravimetric analysis, transmission and scanning electron microscopy. It was found that the change in catalyst support influences HTL pathways and product compositions. The results reveal that the inclusion of FeOx catalyst on Vulcan carbon, SiO2-Al2O3 and ZSM-5 supports can increase the bio-crude yield by ~7–9 wt% compared to their FeOx-free yields. The increase in bio-crude yield was associated with the decrease in the surface ratios of Fe3+/Fe2+ at the range of 0.8–1.6. In overall, catalysts that had higher tendencies in converting amines into oil-soluble compounds increased the bio-crude yield, while catalysts that promoted dehydration and decarboxylation route decreased the bio-crude yield. The maximum energy recovery in bio-crude was obtained using FeOx/SiO2-Al2O3 catalyst with values ~95 %. The deactivation of catalysts was associated with the increase in Ca and P poisonous elements on catalytic sites, which decreased the energy recovery of recycled FeOx/SiO2-Al2O3 to ~85 % after three cycles.

Role of biosynthesized silver nanoparticles in mitigating hyperhydricity in micropropagated watermelon (Citrullus lanatus Thunb.) and assessment of genetic fidelity using RAPD and SCoT markers

Watermelon (Citrullus lanatus) is one of the five most consumed fresh fruits and is a commercially important horticulture crop. The consumer demand for seedless watermelons has considerably increased due to their superior taste and ease of consumption. Seedless watermelon plants are triploids hence plant tissue culture technology which is the cultivation of plant cells, tissues, or organs on specially formulated nutrient media can facilitate the rapid multiplication of seedless watermelon varieties. However, hyperhydricity has been reported as a frequent problem for in vitro growth and development of watermelon. Hence, the present study highlights the application of silver nanoparticles biosynthesized from Parthenium hysterophorus (PHAgNPs) for reversal of hyperhydricity and enhancing in vitro shoot production in watermelon. The biosynthesized PHAgNPs was characterized using UV–vis spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction analysis and Transmission electron microscopy. Cotyledonary nodes used as explant and cultured in three types of cytokinins (BAP, TDZ and KIN) became hyperhydric, losing their ability to regenerate at high cytokinin concentrations (> 1.5 mg/L) irrespective of the cytokinin type. The optimum concentration of BAP (1.0 mg/L) fortified with PHAgNPs (15.0 mg/L) exhibited an improved response of 91 % and induced a maximum of 32.33 shoots with a maximum shoot length of 5.66 cm after 6 weeks. The incorporation of PHAgNPs reduced the percentage of hyperhydricity from 29 % to 1.33 % in regenerated shoots, which was confirmed by the reduction in relative water content (RWC) from 93.33 % to 80.33. Silver ions reduced H2O2 content by 50 % and increased photosynthetic pigments (chlorophyll a, b and carotenoids) by 50 %, which contributed to the formation of healthy regenerated shoots, with opened stomata compared to closed in hyperhydric shoots. Compared with those of hyperhydric shoots, the gene expression patterns of 1-aminocyclopropane-1-carboxylase synthase (ACS1) and 1-aminocyclopropane-1-carboxylic acid oxidase (ACO1) decreased after the retroversion of shoots to 15 mg/L PHAgNP medium. The relative gene expression profiles of ACS1 and ACO1 in hyperhydric shoots were 8.8- and 1.8-fold greater than those in normal shoots, respectively. Profuse root growth was observed in MS basal media supplemented with IBA (1.0 mg/L) and PHAgNPs (10.0 mg/L), which resulted in the greatest number of roots (12.33), with an average root length of 4.33 cm and a response of 89.33 %. The genotoxic effect of PHAgNPs evaluated using RAPD and SCoT molecular markers, showed that the addition of low levels of silver nanoparticles to the medium did not cause any genetic variation. The efficient regeneration protocol standardized in this study provides a solution to solve the problem of hyperhydricity in watermelon regeneration.

Structure and Properties of the Electroexplosive Coating of the TiB2-Ag System after Electron Beam Treatment

A coating of the TiB2-Ag system was formed through the use of sequential operations of electroexplosive spraying and electron beam processing. The values of electrical conductivity (62.0 MS/m), Vickers microhardness (0.251-0.265 GPa at the point of measurement on a silver matrix and 25-32 GPa at the point of measurement at inclusions of boride phases), nanohardness (4.48 ± 0.76 GPa) were determined), Young’s modulus (116±29 GPa), wear parameter under dry friction-sliding conditions (1.2 mm3/N • m) and friction coefficient (0.5). Switching wear resistance during accelerated tests was 7000 on and off cycles with an electrical resistance of 10.01 - 11.76 LiOhm. The thickness of the coatings is 100 microns. The coatings are formed by a silver matrix with inclusions of titanium borides located in it with three types of sizes: nanocrystalline, submicrocrystalline and microcrystalline. Quantitatively, in the structural composition among titanium borides, titanium diboride and silver (56 wt. %) are formed predominantly (41 wt. %), while other titanium borides account for 3 wt. %. Structural transformations are described using complementary methods of X-ray phase analysis, scanning and transmission electron microscopy.

Structural Characterization and Optical Properties of BiFeO3 Nanoparticles Synthesized by Propylene Glycol-Gel Route

This work focuses on the synthesis of phase-pure rhombohedral (R3c) nanocrystalline BiFeO3. The BiFeO3 nanoparticles were synthesized using the sol-gel method with propylene glycol as the complexing agent. The formation mechanism was investigated through thermal analysis and IR spectroscopy. The phase purity, crystal structure and nanocrystalline properties were studied using X-ray diffraction (XRD), Raman spectroscopy and transmission electron microscopy (TEM). The elemental composition and bonding states were analyzed with X-ray photoelectron spectroscopy (XPS). The XRD and Raman spectra confirmed the formation of pure and well-crystallized BiFeO3 nanoparticles at 400 ºC. The optical band gap, determined by UV-visible spectroscopy, was found to be 2.08 eV, indicating that the synthesized BiFeO3 nanoparticles could be an effective photocatalyst in the visible light region.

Research on the Detection Principle of Coal Ash by X-Ray Transmission Based on FLUKA

This study addresses the timely and accurate measurement of coal ash content by proposing a detection model based on nuclear science technology, which is validated using FLUKA 4-4.0 simulation software. The background provided highlights the fact that coal ash content is a critical sales indicator, and its precise measurement is essential for adjusting production parameters in coal preparation plants. In terms of methodology, this study employs the widely used FLUKA4-4.0 software in the field of nuclear physics to simulate X-ray transmission through coal, investigating the impact of changes in coal type on the accuracy of ash measurements. The results indicate that, when the proportions of high-atomic-number elements in coal remain constant, the ash measurement results are accurate and reliable. However, significant fluctuations occur when these proportions change. The conclusion emphasizes the fact that variations in coal type are the primary cause of inaccuracies in ash measurement, particularly when the ratios of high-atomic-number elements are altered. This research provides a new perspective on the online measurement of coal ash content and offers theoretical support for improving measurement accuracy.

Eco-Friendly and Low-Cost Synthesis of Transparent Antiviral- and Antibacterial-Coated Films Based on Cu2O and MIL-53(Al).

This research presents the development of an innovative antimicrobial coating consisting of cuprous oxide (Cu2O) integrated with the metal-organic framework MIL-53(Al) through an eco-friendly and low-cost synthesis method that employs glucose as a reducing agent under mild conditions. The microstructural properties of the composite materials were characterized by using X-ray diffraction (XRD) and transmission electron microscopy (TEM). The antibacterial efficacy of the Cu2O-MIL-53(Al) (CuM) composite was assessed against Escherichia coli and Staphylococcus aureus, achieving a reduction efficacy of 99.99% with 5% copper incorporated into the MIL-53(Al) framework within a contact time of 24 h. The incorporation of CuM into a macromolecular host matrix of polyurethane-carboxymethylcellulose (CuM/PUD-CMC), applied as a coating on a low-cost plastic film, produced a transparent film with 87.10% transparency. This coating demonstrated a 99.99% reduction in E. coli and S. aureus populations within a contact time of 24 h. The CuM/PUD-CMC coating demonstrated substantial antiviral efficacy, achieving inactivation rates of 99.35% for Human Coronavirus 229E, 99.40% for Influenza A virus, and 97.76% for Enterovirus 71 within a contact time of 5 min. The CuM nanoparticles exhibited low toxicity toward zebrafish while effectively eradicating bacteria and inactivating viruses. The proposed low-cost material and coating method demonstrate significant potential as a broad-spectrum antimicrobial and antiviral agent, highlighting its suitability for various applications in biomedical and healthcare formulations.

Covalent Carbide Interconnects Enable Robust Interfaces and Thin SEI for Graphite Anode Stability under Extreme Fast Charging.

Carbonaceous and carbon-coated electrodes are ubiquitous in electrochemical energy storage and conversion technologies due to their electrochemical stability, lightweight nature, and relatively low cost. However, traditional reliance on conductive additives and binders leads to impermanent electrical pathways. Here, a general approach is presented to fabricate robust electrodes with a progressive failure mechanism by introducing carbide-based interconnects grown via carbothermal conversion of (5 wt%) titanium hydride nanoparticles. This method concurrently enhances both electrical and mechanical properties within the electrode architecture. The resulting chemical bonding between active materials establishes a novel mechanism to maintain stable electrical pathways during cycling. Employed as Li-ion battery anodes, these electrodes exhibit improved cyclability, achieving 80% capacity retention after 800 fast-charge cycles at moderate loading (1 mAh cm- 2). High loading cells with areal capacity of 3 mAh cm-2 show significantly improved cycle lifeover the same number of cycles. This performance improvement is attributed to the absence of significant impedance growth and a thinner solid electrolyte interphase (SEI) layer formed at high current densities (4C) as demonstrated by X-ray photoelectron spectroscopy and transmission electron microscopy studies. The enhanced conductivity facilitates SEI formation, lowering ionic impedance and mitigating lithium plating, ultimately leading to the reported extended cycle life.

Size-dependent anatase to rutile phase transition under acoustic shocked conditions – A case study of TiO2 bulk and nanoparticles

In the present work, we attempt to explore the size-dependent structural stability of bulk (0.28 µm) and nano-sized (25 nm) anatase TiO2 particles under acoustic shocked conditions. Based on the observed X-ray diffractometric, Raman spectroscopic and transmission electron microscopic results with respect to the number of shock pulses, at the 90-shocked condition, the nano-size particles undergo the anatase to the rutile phase transition, whereas the bulk size TiO2 particles remain to be in the anatase phase. From the comprehensive assessment, it is demonstrated that the bulk TiO2 samples have higher structural stability compared to the nano-size samples. The nano-sized anatase-TiO2particles have values of lower thermal conductivity compared to the bulk-sized particles such that the value of lower thermal conductivity is a prominent crucial factor in initiating the dynamic recrystallization which results in the anatase-to-rutile phase transition. Based on the observed present experimental results and previous reports, it has been authenticated that, while increasing the particle size from nano-scale to micro-scale, the critical shock number for the anatase to rutile phase transition is significantly increased.

Potential protective efficacy of biogenic silver nanoparticles synthesised from earthworm extract in a septic mice model

Sepsis is an inevitable stage of bacterial invasion characterized by an uncontrolled inflammatory response resulting in a syndrome of multiorgan dysfunction. Most conventional antibiotics used to treat sepsis are efficacious, but they have undesirable side effects. The green synthesised Ag NPs were synthesized by 5 g of the earthworm extract dissolved in a volume of 500mL of distilled water and then added to 2,500 mL aqueous solution of 1mM silver nitrate at 40 °C. After 4 h, the mixture was then allowed to dry overnight at 60 °C. Later, Ag NPs were washed and collected. They were characterized by X-ray diffraction, ultraviolet-visible spectroscopy, and transmission electron microscopy. Sepsis model as induced by feces-intraperitoneal injection method. Eighteen male mice were assigned into three main groups: the control group, the sepsis-model group, and the Ag NPs-treated group. The control group received a single oral dose of distilled water and, after two days, intraperitoneally injected with 30% glycerol in phosphate buffer saline. The Sepsis-model group received a single oral dose of distilled water. Ag NPs - The treated group received a single oral dose of 5.5 mg/kg of Ag NPs. After two days, the sepsis-model group and Ag NPs-treated group were intraperitoneally injected with 200 µL of faecal slurry. Ag NPs treatment in septic mice significantly decreased liver enzyme activities, total protein, and serum albumin. Moreover, Ag NPs significantly enhanced kidney function, as indicated by a significant decrease in the levels of creatinine, urea, and uric acid. In addition, Ag NPs showed a powerful antioxidant effect via the considerable reduction of malondialdehyde and nitric oxide levels and the increase in antioxidant content. The histopathological investigation showed clear improvement in hepatic and kidney architecture. Our findings demonstrate the protective efficacy of biogenic Ag NPs against sepsis-induced liver and kidney damage.

Optical properties and energy transfer of Tm3+ single-doped and Tm3+-Tb3+ co-doped transparent glass-ceramics containing NaGd(MoO4)2 single phase

Tm3+ single-doped and Tm3+-Tb3+ co-doped SiO2–B2O3–Na2O–ZnO–MoO3-Gd2O3 glasses were successfully prepared by the melt-quenching process. X-ray diffraction and transmittance measurements were used to determine that the optimal heat treatment regime consisted of crystallization at 620 °C for 5 h and transparent glass-ceramics containing the NaGd(MoO4)2 single phase were obtained. The characterization results by SEM confirmed that the size of the crystals precipitated in the glass matrix was on the nanometer level. The effects of different contents of Tm2O3 on the luminescent properties of glass-ceramics in this system were explored. The results showed that the emission peak at 453 nm (1D2→3F4) had the highest intensity when Tm2O3 was doped with 0.5 mol% under the wavelength at 359 nm excitation. In addition, with the gradual increase of Tb2O3 contents, the luminescence colour of the Tm2O3–Tb2O3 co-doped glass-ceramics gradually shifted from blue to green. This indicates its potential application in blue-green light display technologies and various other areas. The experimental results of the water resistance stability of the samples show that the co-doped glass-ceramic still has good luminescence stability after being immersed in water, which provides further favourable support for its application.

Tuneable Red and Blue Emission of Bi3+-Co-Doped SrF2:Eu3+ Nanophosphors for LEDs in Agricultural Applications.

Tunable blue/red dual-emitting Eu3+-doped, Bi3+-sensitized SrF2 phosphors were synthesized utilizing a solvothermal-microwave method. All phosphors have cubic structure (Fm-3m (225) space group) and well-distinct sphere-like particles with a size of ~20 nm, as examined by X-ray diffraction and transmission electron microscopy. The diffuse reflectance spectra reveal a redshift of the absorption band in the UV region as the Bi3+ concentration in SrF2: Eu3+ phosphor increases. Under the 265 nm excitation, photoluminescence spectra show emission at around 400 nm from the host matrix and characteristic orange 5D0 → 7F1,2 and deep red 5D0 → 7F4 Eu3+ emissions. The red emission intensity increases with an increase in Bi3+ concentration up to 20 mol%, after which it decreases. The integrated intensity of Eu3+ red emission in the representative 20 mol% Bi3+ co-doped SrF2:10 mol% Eu3+ shows twice as bright emission compared to the Bi3+-free sample. To demonstrate the potential application in LEDs for artificial light-based plant factories, the powder with the highest emission intensity, SrF2: 10Eu, 20 Bi, was mixed with a ceramic binder and placed on top of a 275 nm UVC LED chip, showing pinkish violet light corresponding to blue (409 nm) and red (592, 614, and 700 nm) phosphors' emission.

Manipulating Charge-to-Spin conversion via insertion layer control at the interface of topological insulator and ferromagnet

Strong spin–orbit coupling and highly spin-polarized surface states in topological insulators (TIs) are key parameters that explain their extremely high charge-to-spin conversion (CSC) efficiency at interfaces with ferromagnetic materials (FMs). This study focused on the influence of the insertion layer on the proximity effect occurring in a Co4Fe4B2/Bi2Se3 interface. Various insertion layers, including Au, MgO, and Se, were introduced to modulate the proximity effect from TI to FM and vice versa. X-ray photoelectron spectroscopy and transmission electron microscopy revealed that the Se insertion layer effectively suppresses the formation of an additional Bi layer, reducing intermixing against Co4Fe4B2. Electrical transport properties such as RXX and RXY under a vertical magnetic field show that the Se-inserted structure features the lowest anomalous Hall angle and exhibits a pristine topological surface state, indicating its potential for improving CSC efficiency. The Se-inserted structure exhibits the highest spin Hall angle among various heterostructures, according to results obtained from spin-torque ferromagnetic resonance. These findings highlight the importance of selecting an insertion layer and controlling the interface to optimize the spin-transport properties of TI-based spintronic devices and provide insights into the design of future spin devices.

On-demand performance optimization of AlGaN/GaN high electron mobility transistors using stoichiometric variation of dielectric alloy AlxTayO

The current research investigates the potential advantages of optimally combining wide bandgap Al2O3 with high dielectric constant (high-κ) Ta2O5 for gate dielectric applications. Various compositions of 10 nm AlxTayO oxide films are grown on the Al0.3Ga0.7N/GaN heterostructure by co-sputtering Al and Ta metals, followed by thermal oxidation at 500 °C. The average root-mean-square roughness of the grown oxide films is ∼1.2–1.4 nm compared to 0.4 nm for as-deposited metal. X-ray photoelectron spectroscopy and transmission electron microscopyconfirm the formation and thickness of the grown oxide films. The bandgap (Eg) of the oxide films calculated from O1s electron energy loss spectra show a linear increase from 4.85 eV for pure Ta2O5 to 6.4 eV for pure Al2O3. The dielectric constant (εox) calculated from capacitance–voltage (CG−VG) measurements decreases linearly from 25.7 for Ta2O5 to 7.9 for Al2O3. The interface trap density (Dit) is estimated from the frequency dispersion of capacitance–voltage (CG−VG) characteristics. The DC and radio frequency (RF) characteristics of AlxTayO/Al0.3Ga0.7N/GaN high electron mobility transistor (HEMT) devices are measured and compared with the Schottky HEMT devices (without any gate oxide). Compared to Schottky HEMT devices, AlxTayO/Al0.3Ga0.7N/GaN HEMT devices show superior DC characteristics, which helps us achieve maximum RF output power. Furthermore, the OFF-state measurements show that the AlxTayO/Al0.3Ga0.7N/GaN HEMT devices can sustain higher source-to-drain voltages, from a minimum of 88 V on pure Ta2O5 metal-oxide-semiconductor (MOS)-HEMTs to a maximum of 138 V on pure Al2O3 MOS-HEMTs before the dielectric breakdown happens, compared to a 57 V breakdown voltage on Schottky HEMT devices. An oxide variation of AlxTayO, with Al composition ratio of 0.34, shows an exceptional ION/IOFF ratio of 4 × 1011, a gate leakage current of 8 × 10−12 A/mm, a near-ideal subthreshold slope of 63.8 mV/dec, and the unity current gain frequency (fT) of 25.6 GHz.

Resolving the Role of Configurational Entropy in the Optimization of Mechanical, Thermal, and Microwave Dielectric Properties of SrLa(Al0.50-xGaxZn0.125Mg0.125Ti0.25)O4 Ceramics.

The demand for high-performance microwave dielectric ceramics has surged with the proliferation of fifth-generation (5G) communication networks. In this work, SrLa(Al0.50-xGaxZn0.125Mg0.125Ti0.25)O4 (x = 0-0.20) ceramics were designed by leveraging the unique properties of SrLaAlO4 ceramics and high-entropy engineering. The effects of configurational entropy (Sconf = 1.23R - 1.54R) on the mechanical, thermal, and microwave dielectric properties of SrLa(Al0.50-xGaxZn0.125Mg0.125Ti0.25)O4 ceramics were investigated. X-ray diffractometer and transmission electron microscope analyses confirmed that each composition belonged to the tetragonal structure with a space group of I4/mmm. Significant improvements in Vickers hardness were observed with increasing Sconf, reaching 8.05 GPa at Sconf = 1.54R compared to 5.64 GPa in SrLaAlO4 ceramics. Additionally, the increasing entropy showed great potential in reducing the thermal expansion coefficient (CTE) from 12.32 to 11.49 ppm/°C. The optimal quality factor (Q × f) of 98,000 GHz was achieved at Sconf = 1.37R, attributed to the optimization of intrinsic lattice energy and infrared-damped modes. The temperature coefficient of resonant frequency (τf) was successfully modified toward zero due to entropy-driven CTE and structural modifications. Excellent microwave dielectric properties with εr = 22.5, Q × f = 98,000 GHz, and τf = -2.0 ppm/°C were obtained at Sconf = 1.37R. This work highlights the potential of entropy-engineering in developing high-performance microwave dielectric ceramics, offering a promising pathway for the advancement of 5G communication components.

Corrosion Evaluation and Mechanism Research of AISI 8630 Steel in Offshore Oil and Gas Environments.

In this study, we optimized the traditional composition of AISI 8630 steel and evaluated its corrosion resistance through a series of tests. We conducted corrosion tests in a 3.5% NaCl solution and performed a 720 h fixed-load tensile test in accordance with the NACE TM-0177-2016 standard to assess sulfide stress corrosion cracking (SSCC). To analyze the corrosion products and the structure of the corrosion film, we employed X-ray diffraction and transmission electron microscopy. The corrosion rate, characteristics of the corrosion products, structure of the corrosion film, and corrosion resistance mechanism of the material were investigated. The results indicate that the optimized AISI 8630 material demonstrates excellent corrosion resistance. After 720 h of exposure, the primary corrosion products were identified as chromium oxide, copper sulfide, iron oxide, and iron-nickel sulfide. The corrosion film exhibited a three-layer structure: the innermost layer with a thickness of 200-300 nm contained higher concentrations of alloying elements and formed a dense, cohesive rust layer that hindered the diffusion of oxygen and chloride ions, thus enhancing corrosion resistance. The middle layer was thicker and less rich in alloying elements, while the outer layer, approximately 300-400 nm thick, was relatively loose.

Effect of Ni/Co ratio on Ce-Sc-ZrO2 catalysts for selective H2 production via methane partial oxidation

Partial oxidation of methane (POM) is a promising route for hydrogen production, and achieving a high H2 yield with an H2/CO ratio >3 is highly appealing. Optimization of Ni/Co ratios over Ce-Sc-ZrO2 (CSZ) is investigated for POM reaction and characterized by X-ray diffraction, Raman spectroscopy, temperature-programmed reduction/oxidation/desorption, and transmission electron microscopy. The active site derived from the reduction of “strongly interacted NiO” is responsible for the dissociation of C–H (of CH4), resulting high activity towards POM. 5Ni/CSZ has the highest amount of such active sites and attains the highest activity. 5Co/CSZ catalyst has cobalt-based active sites, and there is an inert carbon deposit during the reaction, causing the least activity. 3.75 wt% Ni and 1.25 wt% Co combination over CSZ support surges the highest density of basicity, oxide vacancy, and adequate amount of active sites derived from “strongly interacted NiO”. The active sites with enhanced metal-support interaction are further grown under exposure to oxidizing gas (O2) and reducing gas (H2) during the POM reaction. The highest density of basicity and oxide vacancy involves more CO2 and H2O in the sequential oxidation of CH4 under indirect pathways. The exclusive involvement of indirect pathways of POM and inhibition of hydrogen consuming reaction (like reverse water gas shift reaction) over 3.75Ni1.25Co/CSZ results into 48 % H2 yield and 3.26 H2/CO ratio up to 24 h time on stream at 600 °C. The H2 yield doubles to ∼97 %, and the H2/CO ratio comes close to 2 over 3.75Ni1.25Co/CSZ catalyst at 900 °C.

Preparation of CeO2@AC and CeO2@NF nanocomposites for waste water treatment

This research focuses on the elimination of Rose bengal dye using nanoparticles consisting of cerium oxide (CeO2) loaded onto activated carbon (CeO2@AC) and carbon nanofibers (CeO2@NF). These nanoparticles were developed through co-precipitation techniques. X-ray diffraction and transmission electron microscopy (TEM) were employed to verify the structural properties and crystalline dimensions of these nanocomposites. The average particle sizes for CeO2, CeO2@AC, and CeO2@NF nanocomposites are determined to be 7.5 nm, 10.5 nm, and 10.0 nm, respectively from XRD. The TEM images shows regularly shaped spherical particles falling within the size range of 7 to 15 nm. Raman spectroscopy and X-ray photoelectron spectroscopy were utilized to investigate their electronic characteristics and the presence of lattice defects, specifically oxygen vacancies, was quantified. The distinctive structure and lattice defects contribute to the photocatalytic degradation of RB dye, with CeO2, AC, and NF exhibiting photocatalytic efficiencies of 75 %, 88 %, and 89.8 %, respectively, when exposed to UV light. Additionally, the magnetic properties of the synthesized samples were examined using a vibrating sample magnetometer. Consequently, cerium oxide nanocomposites combined with activated carbon and nanofibers have demonstrated their utility as multifunctional materials, suitable for photocatalysis.

Marine-derived magnetic nanocatalyst in sustainable ultrasound-assisted synthesis of 2,3-diphenyl-2,3-Dihydroquinazolin-4(1H)-One derivatives

This research presents a sustainable approach to fabricate iron oxide nanoparticles by employing phytochemicals derived from marine grass extract as both reducing and stabilizing agents. Formation of magnetic nanoparticles (MNPs) initially confirmed by ultraviolet–visible spectroscopy (UV–vis) showing absorption peak at 370 nm. X-ray diffraction (XRD) and transmission electron microscopy (TEM) techniques unveiled magnetic iron oxide NPs with a rod shape, an average size of 21 nm, and an inverse spinel crystal structure. The participation of organic compounds in the production and stabilization of MNPs was evidenced through Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA). A vibrating sample magnetometer (VSM) demonstrated the magnetic properties of iron oxide NPs showing a saturation magnetization value of 21.46 emu/g. The catalytic efficiency of these marine-assisted MNPs was evaluated in a one-pot three-component reaction involving isatoic anhydride, aromatic aldehydes, and amines under ultrasonic conditions. Under optimal conditions, a low dose of 1.5 mg of biobased magnetite nanoparticles yielded dihydroquinazolin-4(1H)-One products with up to 95 % efficiency in a brief duration of 15 min at an ultrasonic power intensity of 130 W. Different directing groups were investigated, and control experiments were carried out to enhance the understanding of the reaction mechanism. The obtained results highlight the synergistic effect of marine grass-mediated magnetic nanocatalysts combined with ultrasonic-assisted synthesis in developing sustainable green methodologies in organic synthesis.