Elemental Composition Research Articles

Oxidative stress-induced cytotoxicity of HCC2998 colon carcinoma cells by ZnO nanoparticles synthesized from Calophyllum teysmannii

The field of green synthesis, namely using plant extracts for the production of metal nanoparticles, is rapidly gaining traction. Therefore, this study investigated the process of producing zinc oxide nanoparticles (ZnO NPs) using a water-based extract derived from the stem bark of Calophyllum teysmannii. Notably, this is the first documented utilization of this particular plant source. The presence of a distinct Ultraviolet-Visible (UV-Vis) absorption peak at 372 nm provided evidence for the creation of ZnO nanoparticles. The X-ray Diffractometer (XRD) and Field Emission Scanning Electron Microscopy (FESEM) investigations indicated that the nanoparticles exhibited sizes ranging from 31.5 to 59.9 nm and had spherical morphologies. Energy Dispersive X-ray Diffractometer (EDX) analysis verified the elemental composition of the ZnO nanoparticles, whereas the Fourier Transform Infrared (FTIR) spectra showed clear peaks, demonstrating their production. The FTIR examination of the C. teysmannii extract revealed peaks at around 3370 cm− 1, indicating the presence of phenolic compounds. These chemicals are likely responsible for the reduction and stabilization of the ZnO NPs. The high-resolution X-ray Photoelectron Spectroscopy (XPS) spectra clearly revealed separate peaks corresponding to Zn 2p and O 1s, providing confirmation of the chemical states and bonding contexts. The Raman Spectroscopy analysis revealed a distinct peak at around 425 cm⁻¹, confirming the presence of the wurtzite structure. The harmful effects of ZnO nanoparticles on HCC2998 (a kind of human colon cancer) and Vero (a type of monkey kidney epithelial) cells were evaluated using 3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide (MTT), dichlorodihydrofluorescein diacetate (DCFH-DA), and boron-Dipyrromethene (BODIPY) assays. The cancer cells underwent cell death due to oxidative stress in a dose-dependent manner, as confirmed by microscopic and flow cytometry investigations.

ICRP pregnant-female mesh-type reference computational phantoms part 1: development of fetal phantoms.

The International Commission on Radiological Protection (ICRP) decided to develop pregnant-female reference computational phantoms, including the maternal and fetal phantoms, through its 2007 general recommendations. Acknowledging the advantages of the mesh geometry, the ICRP decided to develop the pregnant-female mesh-type reference computational phantoms (MRCPs) for 8-, 10-, 15-, 20-, 25-, 30-, 35-, and 38-week fetal ages directly in the mesh format. As part of this process, the present study developed the mesh-type fetal phantoms. The reference blood-inclusive organ masses, elemental compositions, and densities were established based on various scientific literatures. Then, the phantoms were developed in accordance with the established reference dataset while reflecting the anatomical features of the developing fetus, such as fetal-age-specific anthropometric parameters, bone ossification, and contents formation time. The phantoms were developed in the tetrahedral-mesh format and can be implemented in the general-purpose Monte Carlo codes (i.e., Geant4, PHITS, MCNP6, and EGSnrc) without the necessity of the voxelization process. To explore the dosimetric impact of the developed phantoms, photon specific absorbed fractions (SAFs) were computed for energies between 10-2 to 101 MeV for the fetal liver and spleen as source regions and self-irradiation and cross-irradiation to the fetal brain, lungs, and urinary bladder wall as target regions. The SAFs showed the fetal-age-dependent dose trends (i.e., SAF decreases with increasing fetal age) due to organ masses increases via fetal growth. The mesh-type fetal phantoms, as part of the ICRP pregnant-female MRCPs, will be used to calculate reference dose coefficients for fetal members of the public for both the current and future ICRP general recommendations.

Novel polyvinyl alcohol-assisted MnO2-ZnO-CuO nanocomposites as an efficient photocatalyst for methylene blue degradation from wastewater.

Pristine ZnO (Z), MnO2 (M), CuO (C) photocatalysts and polyvinyl alcohol (PVA)-assisted MnO2-ZnO-CuO (MZC) nanocomposites were synthesized via the sol-gel method. The synthesized samples were characterized using thermal analysis (TGA), X-ray diffraction (XRD), dynamic light scattering (DLS), scanning electron microscopy (SEM), energy dispersive X-ray (EDS), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM) techniques. The thermal analysis results of the prepared nanomaterial confirmed that the suitable calcination temperature for the synthesis of these nanomaterials is 420 °C. In addition to the morphological and elemental composition, the characteristic diffraction peaks of the MZC nanomaterial were found to align with those of the pristine Z, M, and C photocatalysts. The photocatalytic activities of the synthesized nanomaterials for methylene blue (MB) degradation were evaluated under optimized conditions. The degradation efficiencies of Z, M, C, and MZC were found to be 45%, 57%, 66%, and 93%, respectively, for MB in 180 minutes. The MZC nanocomposite exhibited superior photocatalytic activity compared to the pristine materials, which is attributed to the synergetic effect of the Z, M, and C photocatalysts. The effects of pH, initial dye concentration, and catalyst load were also explored to determine the optimum conditions. The best photocatalytic efficiency was observed at pH 8, with a 130 mg L-1 catalyst load, and a 10 mg L-1 initial dye concentration. The efficiency of the MZC nanocomposite in real textile wastewater was also tested, achieving 80% degradation of pollutants within 180 minutes. Recycling experiments were conducted for four consecutive cycles under optimal conditions. The photodegradation efficiency for the first, second, third, and fourth cycles was 93%, 91%, 90%, and 89%, respectively, demonstrating high consistency in photodegradation performance across the four cycles. Moreover, a Z-scheme photocatalytic mechanism was proposed as a potential mechanism for the MZC photocatalytic system.

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.

Surface Characterization of Bone-Level and Tissue-Level PEEK and Titanium Dental Implant Scan Bodies After Repeated Autoclave Sterilization Cycles

Background: Sterilization is required for any biomedical device intended to be used in contact with the human body. Several studies have reported alterations in the bulk and surface properties of such devices after repeated sterilization cycles. These surface modifications may influence other clinical parameters. Therefore, the aim of this study was to investigate the surface and chemical properties of implant scan bodies (SBs) after consecutive autoclave sterilization procedures. Methods: The objective was to analyze the scan bodies using Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) for chemical analysis and an optical profilometer to analyze the surface roughness. Results: FTIR spectra depicted the appearance of peak at 1741 and 1100 cm−1 due to the diphenyl ether band disappearance. The XPS spectra showed alterations in the elemental composition after autoclaving and roughness were significantly reduced in PEEK BL and TL SBs. Conclusions: These results indicated that some surface modifications were induced by repeated sterilization cycles.

Positive impact of the architecture of the oxygen electrode based on LNO and CGO for solid oxide electrochemical cells

The Ruddlesden-Popper phase, strontium- and cobalt-free lanthanum nickelate, La2NiO4+δ (LNO), is a mixed-conducting oxide phase and a promising oxygen electrode for SOCs (solid oxide electrochemical cells), thanks to its high diffusion of oxygen and its surface exchange properties. The electrochemical performance is strongly related to the charge transfer at the triple phase boundaries in the surface path and the excorporation/incorporation reaction in the bulk path. In this context, this study explores a strategy to increase the number of active sites in LNO-based electrodes, by designing nanostructured active functional layers and incorporating gadolinium-doped ceria (CGO). Two architectural scenarios are proposed compared to a pure LNO reference: a uniform distribution of CGO in the volume of the LNO and a continuous compositional gradient, both fabricated for the first time by electrostatic spray deposition (ESD).These designs are investigated based on phase structure, microstructure, elemental chemical composition, and electrochemical properties using SEM-EDS, XRD, and electrochemical impedance spectroscopy. Polarization resistance values are discussed as a function of the distribution of contact points in the electrode volume and LNO crystallization. The results suggest that the presented approach to achieve CGO: LNO-based gradient electrodes allows controlling the localization of the interfaces between the two phases, thereby optimizing charge transfer.

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.

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.

Electrodeposition of Extremely Cu-Rich CuPd Bimetallic Nanoparticles from an Amide-Type Hydrophobic Protic Ionic Liquid

Abstract Cupric oxide (CuO) and palladium(II) acetate (Pd(Ac)2) were dissolved into the amide-type hydrophobic protic ionic liquid (IL), protonated-betaine bis((trifluoromethyl)sulfonyl)amide ([Hbet][TFSA]), to produce the Cu(II) and Pd(II) species for the electrodeposition of metallic Cu, Pd, and CuPd nanoparticles (NPs). Unlike the electrodeposition conducted in common aqueous electrolytes containing the equivalent amounts of Cu and Pd ions, Cu-rich rather than Pd-rich CuPd co-deposits were obtained from the IL [Hbet][TFSA]; which might result from the retardation of Pd deposition on preferentially electrodeposited Cu surface or the formation of a new metal species when both metal ions co-existed in the IL, leading to an uncommon large overpotential needed to reduce the species into Pd metal. The surface morphologies of CuPd NPs significantly relied on their elemental compositions that could be controlled by the concentration of Pd(II) and/or the applied electrodeposition potential. CuPd NPs with different Pd contents showed very different responses in the reaction current of nitrate reduction. Nevertheless, the CuPd NPs regardless of the Pd contents showed advantages over the Cu nanoparticles in the electrochemical reduction of nitrate, which might be due to the synergistic effects between the Cu and Pd atoms.

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.

Co-valorisation of cassava peel and rice husk to biofuel precursor via intermediate pyrolysis: Kinetics, thermodynamic and pyrolytic oil characterisation

This study explored the co-valorisation of cassava peel and rice husk into biofuel precursors through pyrolysis. The research involved characterization of the biomass, and thermogravimetric analysis at heating rates of 5, 10, and 15 °C/min. An intermediate pyrolysis was conducted using a laboratory-scale setup with a stainless-steel reactor and a Swagelok double-ended tube, yielding pyrolytic oil for analysis. Proximate analysis revealed cassava peel (CP) contains 9.23 wt% ash, while rice husk (RH) has 16.50 wt% ash respectively, while the combined samples of cassava peel and rice husk (CS) had ash content of 74.27 wt%, fixed carbon of 70.07 wt%, and volatile matter of 75.72 wt%. The heating values for the samples were 17.15 MJ/kg, 15.22 MJ/kg, and 17.06 MJ/kg for cassava peel, rice husk, and combined sample respectively. Ultimate analysis indicated the following elemental compositions: CP (40.95 % C, 5.67 % H, 0.22 % N, 0.09 % S, 52.17 % O2), RH (40.15 % C, 5.98 % H, 0.41 % N, 0.78 % S, 52.68 % O2), and the CS (43.06 % C, 6.41 % H, 0.32 % N, 0.41 % S, 49.80 % O2). Kinetic and thermodynamic analysis from the distributed activation energy models revealed average activation energies of 184.95 kJ/mol (CP), 140.56 kJ/mol (RH), and 125.63 kJ/mol (CS). The pyrolysis products consist of 37.50 wt% pyrolytic oil, 11.12 wt% bio-char, and 51.38 wt% non-condensable gases. GC–MS analysis of the pyrolytic oil identified significant amounts of hydrocarbons, phenols, and phenol derivatives, suggesting potential for biofuel production. This study highlights the viability of combined biomass sources for biofuel production and waste to wealth utilization.

Sustainable development of agro bio-mass waste based AA6061-Tungsten carbide hybrid reinforced composites: A comprehensive performance investigation

The Recycling, Reusing, and Reduction (3R) strategy to solid waste management is proposed for exploiting the functionalities of wastes in enhancing base material performance, which could contribute to produce a sustainable product and environment. This study investigates the impact of organic and synthetic ceramic reinforcements; coconut shell ash (CSA), and tungsten carbide (WC) at various concentrations (1, 2, and 3 wt. % each) on microstructural and performance characteristics of sustainable AA6061 based hybrid composites. The composites are produced via the stir casting process with mechanized stirring. The microstructural characteristics of the produced aluminium hybrid composites (AMHC) are evaluated by FESEM/EDAX, FT-IR and XRD studies to examine their elemental composition, morphology and crystalline nature. The mechanical properties are investigated by charpy impact, tensile, compressive and micro-harness studies. The density and porosity analysis are employed to ascertain their physical characteristics. Morphology investigations show that the selected reinforcing materials are present and uniformly dispersed across the matrix's surface. The produced composite with 4 wt. % of CSA and WC reinforcements has the ability to improve the hardness (75.5 %), tensile strength (42.87 %), and compressive strength (55.71 %) of the base Aluminium alloy. Overall, using organic and synthetic ceramic substances as reinforcements for AA6061 alloy can result in sustainable high-performance composites for structural engineering applications across fields.

Enhanced photocatalytic degradation of crystal violet and malachite green oxalate dyes by NiAg2O infused chitosan nanocomposites

The present study investigated the catalysis of Lupeol-loaded chitosan nanoparticles infused with NiAg2O nanoparticles to create a NiAg2O/Lup@CS nanocomposite. Recent advances in nanomaterials with unique architectures and functionalities have successfully treated contaminated soil and industrial wastewaters. Consequently, a lupeol@chitosan nanoparticle loaded with NiAg2O was created, and its catalytic effectiveness in degrading industrial dye pollution was examined. The ionic gelation synthesis route was used to produce the NiAg2O/Lup@CS nanocomposite. After that, the resultant nanocomposite underwent extensive analysis to determine its elemental composition through EDAX, surface bonding, nature, crystallinity using FTIR, FESEM, and XRD, and powdered particle size using HRTEM. Subsequently, the produced nanocomposite's efficacy in photo-catalytically degrading Crystal violet and Malachite green oxalate were evaluated. Moreover, the Crystal violet and Malachite green oxalate degradation kinetics were studied using the Langmuir–Hinshelwood model, which also offered a plausible photocatalytic process. The catalytic mechanism suggested that the addition of Lup@CS nanoparticles would have had the effect of speeding up photocurrent transport by increasing the quantity of electrons and holes produced by the photon's irradiation. This highlights the significance of creating innovative composite photocatalysts. The study also observed the superior photocatalytic activity of NiAg2O/Lup@CS nanocomposite with 86.14 % degradation of Crystal violet and 86.65 % degradation of Malachite green oxalate.

Electrocatalytic trends of different Cantor entropy alloys. for alkaline and acidic hydrogen-evolution reactions

Medium- and high-entropy alloys (MEAs and HEAs) are the basis of unique electrocatalysts for hydrogen-evolution reactions (HERs) due to their tunable chemical compositions and microstructures. Here, various Cantor MEAs (CoFeNi, CoFeNiMn, CoFeNiCr) and a HEA (CoFeNiMnCr) made up of affordable non-noble transitional metals with different structures (primary matrix and secondary phases, grain sizes, lattice parameters) were successfully synthesized with an inert-gas melting process. A close correlation was established between their physicochemical properties (elemental composition, microstructure, crystal structure) and the hydrogen-binding ability of the elements in the alloy on the electrocatalytic HER activity and stability in alkaline and acidic media. Advanced performances of electrocatalysts toward HERs were revealed in a specially designed electrochemical cell. Effectively identifying these electrocatalytic trends lays the groundwork for the strategic design of multi-component alloy electrocatalysts for practical HERs.

Fabrication of ZnIn2S4/CeO2 S-scheme heterojuntion for the enhanced removal of tetracycline under visible light irradiation

A series of S-scheme ZnIn2S4/x-CeO2 heterojunction were designed and fabricated through in-situ precipitation and hydrothermal method. XRD, SEM, TEM, EDX, XPS, UV-vis DRS and adsorption-photocatalytic techniques were employed to investigate its crystal phase structure, morphology, size, elemental composition, photo-response property and elimination ability for tetracycline. XRD analysis revealed CeO2 and ZnIn2S4 in ZnIn2S4/x-CeO2 sample presented cubic and hexagonal phase structure, respectively. SEM and TEM images indicated that CeO2 particles with irregular-shaped of around 20nm were attached on the smooth surface of ZnIn2S4 microparticles with ca. 4 μm. All the as-synthesized ZnIn2S4/x-CeO2 samples could harvest more visible-light and the absorption edges were red-shifted in comparison with pure CeO2. ZnIn2S4/0.3-CeO2 sample exhibited remarkably enhanced photocatalytic performance and its removal efficiency for tetracycline reached 87.29% within 100min. The detailed experimental and DFT calculation indicated that the enhanced photocatalytic property was mainly ascribed to the synergistic effect of wide light-response range, suitable band position and successful fabrication of S-scheme heterostructure, which was in favor of rapid transfer and available separation of photo-generated e-/h+ pairs. The scavenger experiments and the ESR data revealed that the •O2– and h+ active species played the dominant role in tetracycline removal over ZnIn2S4/0.3-CeO2 system. In addition, the as-synthesized ZnIn2S4/0.3-CeO2 samples had excellent stability and the removal efficiency still reached 70.73% after being repeatedly used for 4 times. Furthermore, the possible enhanced photocatalytic mechanism over ZnIn2S4/x-CeO2 was proposed to get a better understanding of photocatalytic process. This work provided the guidance to fabricate CeO2-based heterojunction with promising prospect for the efficient elimination of antibiotic residues from wastewater.

Source variations of atmospheric particles in response to control measures in northern China during 2022 winter olympics and paralympics: Evidence from microscopic analysis.

The physicochemical properties of atmospheric particles including morphologies and composition are directly related to their sources and formation mechanisms. However, most previous studies have been limited to a few sites and small numbers of particles. In this study, we employed computer-controlled scanning electron microscopy (CCSEM) to enhance measurement efficiency and enable long-term observations across multiple sites. To investigate properties and source variations of atmospheric particles in response to control measures before, during, and after the 2022 Winter Olympic Games (WOG) and Winter Paralympic Games (WPG), ambient particles were passively collected in 15 northern Chinese cities and automatically analyzed by an advanced CCSEM (IntelliSEM EPAS). Variations in particle numbers (PN), size distribution, elemental composition, and sources were comprehensively analyzed. Over one million particles were classified into mineral, carbonaceous, fly ash, sulfur-related, metal-containing, salt, and biological particles using the user-defined classification rules. The results showed that improved air quality was witnessed during the WOG with reduced PN and anthropogenic particles, but deteriorated during the WPG due to increased coarse-mode PN, mineral, and sulfur-related particles. Beijing and Zhangjiakou exhibited lower AQI, PN, and anthropogenic particles, while non-competition cities experienced higher levels of anthropogenic and sulfur-related particles. Notably, Taiyuan and Shijiazhuang showed distinct emission reductions during the WOG, while Baoding and Tangshan demonstrated less effective control with high levels of sulfur-related and anthropogenic Fe-rich particles. This study shows the capability of CCSEM to provide microscopic evidence of particle sources and behaviors, offering valuable insights into the efficacy of control measures during major events.

Foliar application of chitosan and brassinosteroids on glutinous rice (‘RD6’): Alteration in growth, agronomic trait, antioxidant capacity, elemental composition and aroma compound, 2-acetyl-1-pyrroline (2AP) in rice grain

Foliar application of chitosan and brassinosteroids on glutinous rice (‘RD6’): Alteration in growth, agronomic trait, antioxidant capacity, elemental composition and aroma compound, 2-acetyl-1-pyrroline (2AP) in rice grain

Electrochemical CO2 reduction to syngas on copper mesh electrode: Alloying strategy for tuning syngas composition

Electrochemical CO2 reduction to synthetic fuels and commodity chemicals using renewable energy offers a promising approach to mitigate CO2 emissions and alleviate energy crisis. Copper-based catalysts show potential for electrochemical CO2 reduction applications, while they face the key challenges of high potential, sluggish kinetics, and poor selectivity. In this work, Cu-Zn, Cu-Co, Cu-Cd, and Cu-In bimetallic catalysts are synthesized via the electrodeposition method for electrochemical CO2 reduction to syngas with adjustable CO/H2 ratios. The bimetallic catalysts are characterized using various techniques to reveal their crystalline structures, morphologies, and elemental compositions. The structure-property-activity relationships of these catalysts are investigated to identify optimal candidates for electrochemical CO2 reduction applications. The findings reveal that the bare Cu mesh catalyst exhibits poor CO2 reduction activity, and the products are dominated by hydrogen evolution reaction (HER). The bimetallic catalysts exhibit improved CO2 reduction performance, with the Cu-Zn and Cu-Cd catalysts showing excellent activity, and the CO/H2 ratio in syngas can be tuned over a wide range by adjusting the applied potential. The Cu-Zn and Cu-Cd catalysts demonstrate outstanding performance with Faradic efficiencies of ∼90 % and ∼80 % towards syngas production with CO/H2 ratios of ∼2.0 and ∼1.5 at −0.81 and −1.01 V vs. RHE, respectively, making the produced syngas suitable for various industrial applications. Stability tests over 450 min show that the Cu-Zn and Cu-Cd catalysts maintain stable catalytic activity, syngas selectivity and CO/H2 ratio, making them robust candidates for syngas production. The results will provide valuable insights into the design of robust catalysts for electrochemical CO2 reduction, offering a promising path toward sustainable syngas production.

Highly selective extraction of gold from wasted random-access memory using a hybrid nanocomposite: Statistical, DFT, and machine learning modeling

This study successfully developed an advanced protocol for recovering gold (Au(III)) from spent random-access memory (RAM) utilizing a mesoporous FeNi2S4 integrated with g-C3N4 nanosheets. The innovative design of this hybrid material proved essential for achieving high efficiency and selectivity in adsorbing Au(III) ions from RAM. Extensive characterization of the g-C3N4 nanosheets and the FeNi2S4@g-C3N4 nanocomposite, covering physicochemical, textural, structural, morphology, and elemental composition, revealed that the strategic incorporation of FeNi2S4 significantly enhanced the composite's adsorption capabilities. The mesoporous FeNi2S4@g-C3N4 composite demonstrated superior performance, with an adsorption capacity of 203.12mg/g at an optimal pH of 2, and retained its high efficiency across more than 10 adsorption-desorption cycles. Furthermore, FeNi2S4@g-C3N4 exhibited strong resistance to interference ions, maintaining over 96% selectivity for Au(III) trapping. Gradient Boosting and Extra Trees models were instrumental in accurately predicting and optimizing the Au(III) adsorption process. The adsorption mechanism was clarified through zeta potential and DFT measurements, identifying strong chemisorption interaction between Au(III) and FeNi2S4@g-C3N4 sorbent. The study concludes that the FeNi2S4@g-C3N4 nanocomposite is an efficient and reusable material for selectively extracting Au(III) from RAM, providing a sustainable and scalable method for recovering valuable metals from complex waste streams, as supported by thorough experimental and computational evidence.

Plant Mediated Synthesis of ZnO Nanoparticles Using Butea monosperma Plant Extract and Their Antibacterial Applications

Plant based nanoparticles (NPs) has become an emerging field in nanotechnology in terms of cost efficiency, less hazardous, biocompatibility and ecologically benignancy. Further, These NPs are being extensively studied for their use as nanomedicines and novel antibacterial agents due to increased growth of hazardous bacteria and their increased resistance to traditional antibiotics. The present studies focused on biosynthesis of zinc oxide (ZnO) NPs using the chloride derivative of zinc and aqueous extract of Butea monosperma (BM) plant and its antibacterial applications on food borne pathogens. Scanning electron microscopy (SEM) reveals the formation of mixed shaped (spherical and hexagonal) ZnO NPs with size ranging between 20-90 nm. The elemental composition of various constituents present in the resulting samples was confirmed from energy dispersive X-ray (EDX). XRD pattern suggested crystalline nature with hexagonal wurtzite structure of ZnO NPs. The Scherrer formula is used to evaluate the average crystallite size of the synthesized NPs ranges from 15 to 85 nm. Furthermore, the Tauc plot method was employed to determine the bandgap energies of the biosynthesized ZnO NPs using UV-visible spectra. These NPs were found to be effective against bacterial strains; Staphylococcus aureus (MTCC 96), Bacillus cereus (MTCC 1272), Stenotrophomonas maltophilia (MTCC 4383), Shigella flexneri (MTCC 1457). Overall, this present research describes that synthesized ZnO NPs hold significant importance as potential antibacterial agents against gram positive bacteria.