Field Emission Scanning Electron Microscopy Research Articles

Enhanced Catalytic Performance for H2 Harvesting from Steam Reforming of Methanol Using Glycine Nitrate Process Synthesized Novel CuFeO2-ZnFe2O4 Porous Nanocomposite Catalyst.

Nowadays, depleting petrochemical resources and global fossil fuel pollution are urgent issues. Hydrogen (H2) has emerged as a promising alternative energy source to combat climate change, the energy crisis, and environmental concerns. However, in the hydrogen energy sector, the storage and transportation of H2 remain challenging. The industrial H2 production path involves the use of steam reforming of methanol, which could effectively avoid the danger of directly using H2. Methanol steam reforming (SRM) offers a safe and practical route for H2 production, leveraging methanol-favorable properties. In this work, a CuFeO2-ZnFe2O4 nanocomposite with enhanced surface area was synthesized via the glycine-nitrate process (GNP) and employed as a catalyst for SRM. Structural and morphological analyses were conducted using X-ray diffraction studies, field emission scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, and BET. The as-combusted nanocomposite exhibited a specific surface area increase from 1.90 to 6.32 m2/g. The best performance achieved was an H2 production rate of 6984 ± 35 mL STP min-1 g-cat-1 (or) 312 ± 2 mmol STP min-1g-cat-1 with a flow rate of 30 sccm at 500 °C, without activation treatment. Based on the establishment, highlight the potential of CuFeO2-ZnFe2O4 nanocomposite as a cost-effective catalyst for on-demand hydrogen generation in fuel cell applications in the future.

Stabilization and solidification of lead, chromium, and cadmium-contaminated clayey sand using calcium hydroxide and sodium carbonate-activated materials.

Stabilization and solidification of lead, chromium, and cadmium-contaminated clayey sand using calcium hydroxide and sodium carbonate-activated materials.

Eco-friendly synthesis of copper nanoparticles by using Ralstonia sp. and their antibacterial, anti-biofilm, and antivirulence activities.

Eco-friendly synthesis of copper nanoparticles by using Ralstonia sp. and their antibacterial, anti-biofilm, and antivirulence activities.

Chitosan/agarose-encapsulated oleic acid-coated magnetite nanoparticles as a chemotherapeutic-loaded scaffold for drug delivery: Physico-chemical and in vitro biological characteristics.

Chitosan/agarose-encapsulated oleic acid-coated magnetite nanoparticles as a chemotherapeutic-loaded scaffold for drug delivery: Physico-chemical and in vitro biological characteristics.

A carbon fiber modified with tin oxide/graphitic carbon nitride as an electrochemical indirect competitive immuno-sensor for ultrasensitive aflatoxin M1 detection.

A carbon fiber modified with tin oxide/graphitic carbon nitride as an electrochemical indirect competitive immuno-sensor for ultrasensitive aflatoxin M1 detection.

Copper-induced microstructural alterations in the chitin-protein matrix and calcium dissolution in the exoskeletal carapace of the mud crab Scylla serrata.

Copper-induced microstructural alterations in the chitin-protein matrix and calcium dissolution in the exoskeletal carapace of the mud crab Scylla serrata.

Application of electrodeposition for Nickel Nanoparticle-Modified Electrodes in Biochemical Systems.

Microbial fuel cells (MFCs) have garnered significant attention from researchers as an innovative and environmentally friendly method for the treatment of urban and industrial wastewater. The type and material of the electrode are critical factors affecting the efficiency and energy production of this process. The electrodeposition method was employed to dope nickel (Ni) and modify the surface of graphite plates (GP) and carbon felt (CF). The maximum voltage, current density, and power generated by the MFC were evaluated under consistent temperature conditions. Field-emission scanning electron microscopy (FE-SEM) results confirmed successful Ni doping and adequate microorganism attachment to the Ni-deposited electrodes, leading to enhanced electron transfer and increased power generation. Additionally, the highest average voltage output was observed using modified bio-Ni@CF (468.0 mV) and bio-Ni@GP (422.0 mV) electrodes, compared to bare CF (382.0 mV) and GP (301.0 mV) electrodes. Monitoring the open-circuit voltage (OCV) data for four loadings of the MFC with different anodes indicated the suitable resistance and stability of the Ni film over time. Therefore, the electrodeposition method can be considered a suitable technique for modifying the anode electrodes using Ni in MFCs.

Green and facile upcycling of spent alkaline battery anodes to zinc oxide nanoparticles for catalytic application in organic synthesis.

Green and facile upcycling of spent alkaline battery anodes to zinc oxide nanoparticles for catalytic application in organic synthesis.

The green formulation of silver nanoparticles for the anticancer and lupus nephritis treatment applications and reducing the inflammatory cytokines in the rat periodontal model

The green formulation of silver nanoparticles for the anticancer and lupus nephritis treatment applications and reducing the inflammatory cytokines in the rat periodontal model

Synergistic effects of Co-Ni nanoalloys on SiO\(_{2}\)@TiO\(_{2}\): A novel approach to photocatalytic tetracycline degradation

To develop a cost-effective alternative to noble metal catalysts for photocatalysis, we synthesized a series of bimetallic Co-Ni nanoalloys on core-shelled SiO2@TiO2 nanostructures via a chemical reduction approach. The research demonstrates the photocatalytic behaviour of the Co-Ni alloy-enhanced SiO2@TiO2 (ST-Co, Ni) hybrid nanocatalyst, focusing on its crystalline structures, morphological shapes, chemical conditions, and optical properties, utilizing techniques such as X-ray diffraction, field emission scanning electron microscopy, UV-visible diffuse reflectance spectroscopy, photoluminescence spectroscopy, transmission electron microscope, and electrochemical analysis. The catalyst was evaluated for its effectiveness in degrading tetracycline, an overused antibiotic that persists in aquatic environments and is known for negatively impacting water quality. The Co-Ni nanoalloys were tested in various ratios (1:1, 1:2, 2:1), with the 1:1 ratio (ST-Co, Ni1:1) emerging as the most effective, achieving a degradation rate of 88.4% at pH 5 in 120 min. This optimal catalyst demonstrated superior charge carrier separation and enhanced absorption of solar radiation in the visible spectrum. Improved solar light absorption and surface plasmon resonance work in concert to promote effective charge transfer from the nanoalloys to the titania, which is probably the cause of the observed photocatalytic degradation rates. So the proposed hybrid nanocatalyst paves the way for photocatalysis and can be suitable for different photocatalytic processes.

Investigating the Lubrication Properties of PAO-4 Oil with Hybrid GO/Fe2O3 Nanocomposite Additives

Abstract Nanoparticles (NPs) significantly enhance lubrication performance by reducing friction and wear through mechanisms such as the mending effect, rolling effect, and the formation of protective films. Furthermore, combining two or more NPs can lead to the development of new materials that exhibit enhanced performance and increased multifunctionality. This study employed a sonochemical method to synthesize hybrid NPs comprising graphene oxide (GO) and iron oxide (Fe2O3). Subsequently, these NPs were incorporated as additives in Polyalphaolefin (PAO-4) oil. Characterization techniques such as X-ray diffraction, Field Emission Scanning Electron Microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and Energy Dispersive X-ray spectroscopy were used to analyze the morphological and chemical properties of prepared hybrid NPs. The nanolubricants (NLs) were prepared by dispersing GO and GO/Fe2O3 NPs in PAO-4 oil. The rheological properties of the developed NLs were assessed using a rheometer at 40 °C and 100 °C. The tribological tests were also performed on a universal tribometer under different load conditions (5, 15, 25 N). The experimental findings demonstrated that the presence of a hybrid GO/Fe2O3 nano additive enhanced the tribological performance of PAO-4 oil compared to other samples. Notably, the NLs based on GO and GO/Fe2O3 NPs exhibited exceptional coefficient of friction (COF) and wear properties compared to base (PAO-4) oil. Raman spectroscopy analysis revealed the presence of a protective GO/Fe2O3 tribofilm on the worn surfaces, contributing to a reduction in the COF and roughness of worn surfaces.

A study on the utilisation of graphene-based nanofluids to enhance heat transfer in double pipe heat exchangers

ABSTRACT This study aims to synthesise graphene nanoparticles via a modified Hummers method and evaluate their efficacy in improving heat transfer in double-pipe heat exchangers. X-ray diffraction (XRD) analysis confirmed the semi-crystalline and amorphous nature of the graphene oxide, with a pronounced peak at a Bragg angle of 2θ = 16° and an interlayer spacing of 8.5 Å. Fourier transform infrared (FTIR) spectroscopy detected characteristic C–O–C and C=C vibrations, confirming the presence of graphene oxide’s functional groups. Field emission scanning electron microscopy (FESEM) showed flake-like particles averaging 126 nm. The addition of 0.01% graphene oxide nanoparticles to the base fluid significantly improved heat transfer, enhancing LMTD, Reynolds number, OHTC, effectiveness, CHTC, and friction factor. These gains are attributed to the nanoparticles’ high surface area and agglomeration, demonstrating their potential for efficient heat transfer applications.

Digitally coded carbon ink based reflective surface (RS) for anomalous reflection

Abstract In this paper, we propose the design of a 1-bit digitally coded resistive
 carbon ink-based reflective surface (RS) for achieving anomalous reflection-based beam
 steering. The proposed surface operates within the industrial, scientific, and medical
 (ISM) band at 5.8 GHz (5.5–5.9 GHz). The unit cell features a simple structure
 consisting of a bottom metal layer, an FR-4 substrate, and a carbon ink patch on
 top of a polyimide layer. The polyimide layer, positioned between the patches and
 the FR-4 substrate, enhances the durability of the structure. The reflective surface
 achieves a 1-bit phase shift resolution by varying the size of the patch, with a 10 mm
 patch serving as element-0 and an 11.5 mm patch as element-1. At 5.8 GHz, these
 two patch sizes produce a perfect 180-degree phase difference. The sheet resistance
 of the carbon ink is optimized to 3 Ω/sq to ensure high reflectivity. The patches are
 fabricated using a cost-effective screen-printing technique and are characterized for
 morphology using field emission scanning electron microscopy (FESEM) and surface
 roughness. A 16 × 10 array with dimensions of 320 mm × 200 mm is developed and
 tested for two configurations. The first configuration redirects the beam to θr = 20°.
 while the second is towards θr = 32°. The proposed surface exhibits a maximum gain
 of 15.5 dBi with a side lobe level (SLL) of −9.2 dB for pattern-1, and a gain of 14.4 dBi
 with an SLL of −7.9 dB for pattern-2, maintaining stable performance over a 400 MHz
 bandwidth. Experimental validation includes radiation pattern measurements and
 received signal power. The RS-enhanced signal strength is further validated through
 comparison with the theoretical free-space path loss (FSPL) model. Additionally,
 the proposed reflective surface mitigates angular non-reciprocity, ensuring consistent
 performance in time division duplex (TDD) wireless communication systems.

Green Synthesis of Cu-Zn Bimetallic Nanoparticles via Trifolium alexandrinum Extract: Structural Characterization, Biochemical Potential and Photocatalytic Application

The goal of this study was to synthesize the bimetallic nanoparticles using leaf extract of Trifolium alexandrinum, copper sulphate and zinc sulphate and screening their biological and photocatalytic activities. Since growing antibiotic resistance is a significant problem, metallic nanoparticles, which are well-known for their wide biological spectrum, are proving to be an efficient substitute for currently available antibiotics. Leaf extract of T. alexandrinum (TFL) and its bimetallic Cu-Zn (CZS) nanoparticles have been synthesized. Fourier transform infrared spectroscopy, ultraviolet spectroscopy, transmission electron microscopy, field emission scanning electron microscopy, X-ray diffraction and energy dispersive X-ray were used to analyze and characterize the synthesized nanoparticles. The Fourier transform infrared spectroscopy describes the presence of different functional groups in the leaf extract as well as changes in their nature after combining with metal salts. Field emission scanning electron microscopy reveals the formation of nanoparticles in agglomerated form with spherical shape. Transmission electron microscopy images also coincide with the results of scanning electron microscopy. The X-ray diffraction pattern confirms the formation of crystalline nanoparticles with 77% crystallinity with an average size of about 50-150 nm, whereas EDX certifies the presence of different constituent abundances in the form of percentage. Further, the biological potential of the obtained nanoparticles was estimated by evaluating the antimicrobial and anti-angiogenic activities. The maximum value for bacterial inhibition was found to be 21.5 mm and for fungal inhibition this value reaches to 20 mm for 100 µL each. The percentage inhibition on vessel growth rate in TFL/CZS nanoparticle treated groups was obtained as 28% (1 µg) and 85% (10 µg). Percentage degradation for the composite was attained 83%, which was much better than CZS nanoparticles towards the Congo red dye. Results have shown that subjected nanoparticles were proven as excellent biological agents. Moreover, the photocatalytic activity confirms that the novel bimetallic nanoparticles can be used to treat the wastewater at initial level.

Enhancing latent heat thermal energy storage efficiency: thermal performance analysis of phase change material enriched with TiO2 nanoparticles

Abstract This work examines the capacity of titanium dioxide (TiO2) nanoparticles to improve the thermal efficiency and characteristics of phase change materials (PCMs) in latent heat thermal energy storage (LHTES) systems. The TiO2 nanoparticles were introduced in varying concentrations of 0.5%, 1.0%, 1.5% and 2.0%. The effect of varying concentrations of TiO2 nanoparticles on thermal conductivity (TC), melting and solidification time, and charging and discharging efficiency was studied and compared with paraffin wax at different flow rates (0.5 LPM, 1.0 LPM and 1.5 LPM). A total of 4 samples were prepared using a magnetic stirrer. Fourier Transform Infrared Spectroscopy (FTIR) is employed to analyze chemical interactions, while Field Emission Scanning Electron Microscopy (FESEM) is used to analyze the distribution of nanoparticles in the PCM matrix. The tests demonstrate that the TiO2 nanoparticles are evenly distributed inside the PCM matrix and have no harmful chemical interactions. In addition, Thermogravimetric Analysis (TGA) is utilized to assess the thermal stability of the nano-enhanced PCM (NEPCM). The TGA results demonstrate the improved resistance to heat degradation of the NEPCM, which is crucial for the long-term operation of the LHTES system. Each sample’s thermal conductivity and pure paraffin wax were also checked using a hot disk TPS 500 instrument. The findings demonstrate that the addition of TiO2 nanoparticles enhances the thermal conductivity of the PCM by 35%, 53%, 69.5%, and 88% at 0.5, 1.0, 1.5, and 2.0% when compared with pristine PCM. The improved thermal conductivity resulted in faster heat transfer rates during the charging and discharging. Compared with paraffin wax, at an HTF flow rate of 0.01 Kg s−1, the NEPCM containing 0.5% TiO2 improved the charging, discharging, and overall efficiencies around 2.89%, 5.21%, and 2.25%, respectively. This research offers vital knowledge on the advantages of using TiO2 nanoparticles to enhance the thermal efficiency and behaviour of PCMs in LHTES systems. This opens up possibilities for more effective and environmentally friendly energy storage solutions in applications like batteries, food storage, buildings, HVAC, etc.

Genesis of anhydrites in the dolomite facies of the oligo-miocene Asmari formation, Zagros basin: implication for reservoir quality

The type and amount of distribution of evaporite minerals within reservoir rocks play important role in reservoir quality. This study focuses on thin section petrography, field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, aqueous fluid inclusions microthermometry, and UV fluorescence microscopy of hydrocarbon fluid inclusions, to study the genesis of anhydrites within dolomite facies of the Oligocene-Miocene Asmari Formation, Zagros Basin. Petrographic studies of primary (dolomicrite) and secondary (dolosparite) dolomite-dominated facies of the Asmari Formation showed that the associated diagenetic anhydrites occurred in different morphological textures (forms) including poikilotopic, pervasive pore-filling, scattered pore-filling, fracture-filling, and vein cements, nodular and layered forms. Fluid inclusion studies of anhydrites revealed that the diagenetic anhydrites particularly within the dolomicrite facies were formed at an average temperature of 68.2 °C, and by mineralizing solutions with salinity of about 23.5 wt% NaCl. Indeed, in the dolomicrite facies, the anhydrites were associated with gypsum dewatering and/or direct anhydrite precipitation during eodiagenesis. In contrast, in the dolosparite facies, anhydrites were formed at an average temperature of 100.1 °C, and by mineralizing solutions with salinity of about 16.4 wt% NaCl. This latter condition was very likely related to the dolomitization processes including the creation of calcium-rich and magnesium-poor pore fluids with presence of sufficient sulfate ions during the mesodiagenesis. Occurrences of eugenic and mesogenic anhydrites within the dolomite facies were largely controlled the petrophysical parameters as well as the reservoir quality of the Asmari Formation.

The Hydrogen Storage Properties and Catalytic Mechanism of the AZ31-WS2 Nanotube/Pd Composite

Magnesium-based alloys, known for their high hydrogen storage capacity, suffer from sluggish kinetics and high activation energy barriers. It can be further optimized through synergistic combinations with metal hydrides. This study aims to address these limitations by investigating the hydrogen sorption properties of AZ31 magnesium alloy combined with different compositions of WS2 nanotubes (NTs) and Pd. The materials AZ31, WS2 (tungsten disulfide) NTs, and Pd were pre-processed via the mechanical ball milling process. Field emission-scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) were employed to investigate the composite morphology and confirm the nanotubular structure of WS2. This work is among the first to explore the synergistic catalytic effects of WS2 nanotubes and Pd on the hydrogenation/dehydrogenation behavior of AZ31 alloys. The composite with 8 wt.% WS2 NT/Pd demonstrated the fastest hydrogen sorption kinetics and a significant reduction in activation energy, from 123.25 kJ/mol to 104.58 kJ/mol. These results highlight the enhanced dehydrogenation performance of AZ31 through catalyst inclusion, offering a promising approach to improve hydrogen storage materials. These findings highlight the potential of combining inorganic NTs and transition metals as effective catalysts to enhance the hydrogen storage performance. This research paves the way for developing advanced hydrogen storage materials with improved performance, contributing to a sustainable energy future.

Study the Structural and Morphological Properties of Nano/Micro Polystyrene Treated by Argon Plasma and Apply as the Antibacterial Application

In this study, plasma parameters in DC glow discharge of argon gas were used for the pure PE film untreated and exposed of argon gas plasma (10, 20 and 25) min samples treatment. X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM) were studied for the morphological and structural films. X-ray diffraction patterns of all samples prepared were recorded. The XRD pattern shows the pure PE unexposed that the polycrystalline nature with strong peak around 2θ =21.51° with miller indices (110). After exposed with the argon plasma (10, 20 and 25) min and change the electrode distance (2.5, 3.5 and 4.5) cm, the new peak exhibited and the intensity of the all peaks increased with increasing exposed time, indicating that the orientation of the orthorhombic crystals had changed and also indicate the time exposed of argon plasma was affected. The increase in grain diameter average and particle size for pure PE film and exposed of argon gas plasma (10, 20 and 25) min with an increase in the treatment with dc glow discharge plasma was noted in the FESEM images. The contact angle of untreated pure PE and PE films after exposed of argon gas plasma (10, 20 and 25) min was measured at room temperature with water appeared of the contact angle results decrease with increasing time exposed plasma. The antibacterial activity for the pure PE film untreated and exposed of argon gas plasma (10, 20 and 25) min shows enhanced antibacterial activity against E. coli and S. aureus due to the changes in surface chemistry and physical structure, including increased hydrophilicity, surface roughness, and the generation of reactive species that can damage bacterial cells.

Nanoencapsulation enhances stability, release behavior, and antimicrobial properties of Sage and Thyme essential oils

The increasing demand for natural bioactive compounds in agriculture, food preservation, and pharmaceuticals has highlighted the need for effective delivery systems to enhance their stability and bioavailability. In this study, we address this challenge by developing and characterizing silica hollow nanospheres (HNSs) and hollow polymer nanocapsules (HPNs) for the encapsulation of essential oils (EOs), specifically those derived from Thyme (Thymus vulgaris) and Sage (Salvia officinalis). The HNSs were synthesized using tetraethyl orthosilicate (TEOS) via a sol-gel process, while urea-formaldehyde HPNs (UF–HPNs) were fabricated through in-situ polymerization. The qualitative encapsulation efficiency, structural integrity, and release behavior of the EOs were analyzed using Fourier transform infrared spectroscopy (FT–IR), field emission scanning electron microscopy (FE–SEM), and dynamic light scattering (DLS). The results demonstrated that HNSs, particularly those synthesized via in-situ techniques, exhibited superior size uniformity, higher oil loading capacity (4.18 mg/g), and controlled release performance over 102 days. Adsorption studies revealed that HNSs provided higher adsorption capabilities for Thyme EO, aligning with the Freundlich and Temkin isotherm models. Antimicrobial studies revealed that encapsulated Thyme EO exhibited strong antibacterial activity, with MIC values of 4 µL/mL against Escherichia coli (E. coli) and 2 µL/mL against Staphylococcus aureus (S. aureus), while Sage EO required higher concentrations, with MIC values of 8 µL/mL and 4 µL/mL, respectively. Notably, the encapsulation of Thyme EO in HNSs resulted in enhanced antimicrobial performance compared to HPNs, likely due to the porous silica matrix allowing for sustained EO release. The encapsulated EOs also modulated peroxidase enzyme activity, further supporting their potential for biological applications. These findings suggest that HNS-based encapsulation offers a robust and sustainable approach for enhancing the efficacy of natural antimicrobial agents, making them suitable for industrial applications in biopesticides, food safety, and therapeutic formulations.

Green synthesis, characterization and bioactivity analysis of eco-friendly silver nanoparticles using Schefflera actinophylla flowers

Abstract The synthesis of nanoparticles (NPs) has gained prominence due to their distinct properties and wide-ranging applications. Among various methods, green synthesis stands out for its environmentally friendly approach. This study investigates the green synthesis of silver nanoparticles (AgNPs) using the aqueous extract of Umbrella plant flowers (Schefflera actinophylla). Phytochemical analysis of the extract identified the presence of alkaloids, terpenoids, saponins, resins, carbohydrates, and phenols. Silver nanoparticles were synthesized using a 0.1 M AgNO3 solution and monitored through UV-visible spectroscopy, which revealed an absorption peak at 370 nm. Characterization through infrared (FTIR) spectroscopy, Field Emission Scanning Electron Microscopy (FE-SEM), Dynamic Light Scattering (DLS), and Zeta potential measurements indicated an average particle size of 8.9 nm and a zeta potential of −8.8 mV. FE-SEM images showed nanoparticles in various shapes. The AgNPs exhibited significant antimicrobial activity against common bacteria such as Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa, and Escherichia coli, as well as fungi including Aspergillus niger and Candida albicans. Furthermore, the nanoparticles displayed notable antioxidant activity with an IC50 value of 37.025 μg/ml. This study highlights the benefits of using plant-based methods for nanoparticle synthesis, offering an eco-friendly alternative to conventional chemical processes, thus reducing pollution and mitigating antibiotic resistance in microbes.