Field Emission Transmission Electron Microscopy Research Articles

Layer-by-Layer Deposition of Hollow TiO2 Spheres with Enhanced Photoelectric Conversion Efficiency for Dye-Sensitized Solar Cell Applications

Fabricating photoanodes with a strong light-scattering effect can improve the photoconversion efficiency of dye-sensitized solar cells (DSSCs). In this work, a facile microwave hydrothermal process was developed to prepare Au@TiO2 core–shell nanostructures, and then the Au core was removed by etching, resulting in hollow TiO2. Morphological characterizations such as field emission scanning and transmission electron microscopy measurements have been used for the successful formation of core–shell and hollow TiO2 nanostructures. Next, we attempted to deposit the different-sized hollow TiO2-based microspheres simultaneously on the surface of small-sized TiO2 nanoparticles-based compact film as light-scattering layers via electrophoretic deposition. The deposited hollow TiO2 microspheres constitute bi- and tri-layers that not only improve the light-harvesting properties but also speed up the photogenerated charge transfer. Compared to commercial TiO2 compact film (4.75%), the resulting bi-layer and tri-layered films-based DSSCs displayed power conversion efficiencies of 6.33% and 8.08%, respectively. It is revealed that the deposited bi- and tri-layered films can enhance the light absorption ability via multiple photon reflection. This work validates a novel and controllable strategy to develop light-scattering layers with increased light-harvesting properties for highly efficient dye-sensitized solar cells.

Co3O4/rGO based nanocomposite architectures as electrodes for advanced energy storage and their pseudocapacitive attributes

In response to escalating global challenges in energy storage, this study embarked on captivating exploration of electrochemically proficient Co3O4 composites, seamlessly integrated with varying concentrations of reduced graphene oxide (5 %, 10 %, and 15 %). Using a single-step hydrothermal method, Co3O4 was synthesized, followed by a solvothermal process to produce Co3O4/rGO composites. These composites were then applied to Nickel Foam to fabricate electrodes. The structural properties of these novel Co3O4/rGO/NF electrodes were analyzed using X-ray Diffractometer, which confirmed the distinctive crystalline structure of Co3O4 and indicated no phase transformation after the introduction of rGO. Morphological analysis through a Field Emission Electron Microscope and Transmission Electron Microscope revealed layered structures and increasing porosity correlated with higher rGO concentrations. Electrochemical performance was rigorously tested through cyclic voltammetry, which verified the pseudocapacitive attributes of the samples. Additionally, galvanostatic charge-discharge studies highlighted that the electrode containing 15 % rGO demonstrated highest (Cs = 1360 Fg−1) at 1.7 Ag−1, with 86 % of cyclic retention after 5000 cycles. Electrochemical impedance spectroscopy further demonstrated superior conductivity, underscoring the potential of these electrodes'for supercapacitor applications.

Damping and acoustic properties of nanosilica filled poly(styrene-acrylate) interpenetrating polymer networks (IPNs): Effect of nanocomposite preparation method

Research on noise pollution reduction has focused on utilizing damping coatings and polymer nanocomposites to enhance sound absorption. Nanosilica/poly(styrene-acrylate) nanocomposites as a water-based coating were prepared through in-situ emulsion polymerization and direct mixing methods at varying concentrations of 1, 2, and 3 wt% of nanosilica. Fourier transform infrared (FTIR) spectroscopy revealed that the inclusion of surfactant-containing micelles and a more extended synthesis period in the in-situ synthesis technique enhanced the interaction between silica nanoparticles and polymer chains. Dynamic light scattering (DLS) analysis showed a unimodal distribution and an acceptable range of polydispersity index (PDI) for neat and nanocomposite latexes. The addition of silica nanoparticles enhanced the stability of latex particles, especially evident in the direct mixing method. The field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) images confirmed the better dispersion of nanoparticles within the polymer matrix in the in-situ method. The addition of nanosilica resulted in a significant increase in pseudoplastic behavior and viscosity, notably in the in-situ synthesis. In both the in-situ synthesis and direct mixing techniques, the addition of 1 wt% of nanosilica resulted in an increase in the damping factor of nanocomposite films to about 2. However, when the nanosilica content was further increased to 3 wt%, the damping factor decreased. Acoustic tests demonstrated improved sound absorption with silica nanoparticles, yielding noise reduction coefficient (NRC) values of 0.49 and 0.46 for in-situ synthesis and direct mixing. The direct mixing method notably enhanced tensile properties at all nanoparticle content levels. Dried nanocomposite films exhibited superior UV-blocking capabilities compared to neat polymer films.

One-pot synthesis of graphene nanosheets‑nickel cobalt LDHs nanocomposite for electrocatalysis of oxygen evolution reaction

Oxygen evolution reaction (OER) is known as a bottleneck for the overall water-splitting process due to its slow kinetics. In this regard, constructing a high-performance, cost-effective electrode material may act as a game changer. Here, a 2D/2D nanocomposite has prepared out of graphene nanosheets and nickel‑cobalt layered double hydroxide (NiCo LDH) by a simple solvothermal method. The 2D flower-like structures of NiCo LDH attached to graphene nanosheets have observed in field-emission scanning (FE-SEM) and transmission (TEM) electron microscopy images. The X-ray diffraction (XRD) patterns have revealed the formation of Ni(OH)2 and Co(OH)2 lattices along with hexagonal graphene crystals. X-ray energy dispersive spectroscopy (EDS) has noted the 2.2:1 ratio of nickel to cobalt in the graphene/NiCo LDH nanocomposite. X-ray elemental maps have shown the uniform distribution of elements in the sample, and the corresponding functional groups have observed in the Fourier-transform infrared (FTIR) and Raman spectra. X-ray photoelectron spectroscopy (XPS) has determined the coexistence of divalent and trivalent metals in the nanocomposite. The N2 adsorption-desorption study has shown signs of slit-shaped ion-accessible micro and mesopores with high specific surface area for the nanocomposite. It has benefited the ion diffusion process during the exposure of the modified electrode to the electrolyte. The graphene/NiCo LDH nanocomposite has provided the onset potential of 1.56 V, overpotential of 338 mV at 10 mA cm−2, Tafel slope of 69 mV dec−1, charge-transfer resistance (Rct) of 27 Ω, double layer capacitance (Cdl) of 24 μF, electrochemically surface area (ECSA) of 0.6 cm2, and roughness factor (RF) of 20. The electrode has maintained 98.3 % of its initial signal after 10 h continuous measurement at OER potential. This electrocatalytic activity refers to the sheet-like morphology, effective hydroxide ion transfer through interlayer spaces, enhanced conductivity, and high chemical stability achieved by a constructive synergy between graphene nanosheets and NiCo LDH.

Dysprosium chromite nanoparticles: A promising photocatalyst for the remediation of ciprofloxacin and methylene blue from wastewater

A facile sol-gel synthesis method was employed to synthesize dysprosium chromite (DyCrO3) nanoparticles (NPs), which were subsequently calcined at 750 ∘C to investigate their structural, optical, and photocatalytic properties. Rietveld refinement of powder X-ray diffraction patterns revealed a single-phase orthorhombic structure for the DyCrO3 NPs, exhibiting good crystallinity and belonging to the Pbnm space group. Furthermore, Field Emission Scanning Electron Microscopy and Transmission Electron Microscopy imaging revealed a promising morphology with an average particle size of 30 ± 7 nm. Optical assessments indicated an energy band gap of 2.72 eV, suggesting potential for solar light harvesting as a photocatalyst. Mott-Schottky plots confirmed the n-type semiconductor behavior of the DyCrO3 NPs, and valence band X-ray photoelectron spectroscopy analysis supported these findings. Electronic band structure calculations showed a substantial conduction band minimum and a positive valence band maximum, essential for promoting oxygen reduction and oxidation reactions, respectively, which are crucial for photocatalytic activity. Moreover, the synthesized DyCrO3 NPs demonstrated significant potential as efficient photocatalysts, effectively decomposing the antibiotic ciprofloxacin (CIP) under solar light. Notably, the DyCrO3 NPs achieved 83 % degradation of CIP within 240 min of solar irradiation. Similarly, under identical conditions, the DyCrO3 NPs photocatalyst showed promise in degrading 70 % of the colored organic pollutant methylene blue (MB). Interestingly, during the first 120 min, the degradation of CIP was approximately 25 % greater than that of MB. The ability of DyCrO3 NPs to efficiently degrade both colored and colorless pollutants highlights the catalyst’s inherent photocatalytic nature, rather than merely relying on dye-sensitization effects. Furthermore, the presence of DyCrO3 NPs reduced the activation energy for CIP degradation from 31.657 kJ mol−1 K−1 to 20.846 kJ mol−1 K−1, providing additional evidence of their true catalytic efficacy. Apparent quantum yield values of 40 % for CIP and 35 % for MB degradation further illustrate their superior solar energy harvesting ability. A comprehensive mechanism was developed to explain the impressive photocatalytic performance of the synthesized NPs, highlighting their potential in degrading pharmaceutical antibiotics.

Synthesis, Structural, Morphology and Magnetic Properties: Effect of La on Multiferroic Nature of BiFeO3 Nanoparticles

Objectives: The present study focuses on developing La-doped BiFeO3 multiferroic materials for dielectric absorber applications. Methods: The samples are characterized by X-ray Diffractometer (XRD). Further, the morphology is examined using field emission electron microscopy (FESEM) and Transmission Electron Microscopy (TEM). The dielectric parameters and ac-electrical parameters are carried out by impedance spectroscopy. The magnetic properties are studied using a vibrating sample magnetometer VSM, P-E loop. Findings: XRD confirms the rhombohedral (trigonal) structure of BLFO nanoparticles. The grain and particle size values are determined by SEM and TEM, respectively. The dielectric and ac-electrical parameters for all the samples are thoroughly discussed at room temperature. The Maxwell-Wagner or interfacial polarization is noticed at low input field frequencies for x=0.2-0.8. The impedance analysis shows the contribution of grain and its boundary in the electrical conduction mechanism. The multiferroic behavior is examined using M-H loops, P-E loops, and μi-f plots. Novelty: The samples are synthesized by the hydrothermal process to prepare La-doped BiFeO3 nanomaterials. Keywords: Nanoparticles, Electron Microscopy, Multiferroic, Magnetization, Polarization, Permeability

Nanostructural evolution by applying various fuels in combustion design of CuZnAl mixed-oxides over HZSM-5 used in one-step production of CH3–O–CH3

The influence of different fuels (urea, ethylene glycol and citric acid) in combustion-based design of nano-structured CuO–ZnO–Al2O3/HZSM-5 catalyst was investigated. The catalytic performance were evaluated in a single step production of dimethyl ether form syngas. The X-ray diffraction, Field emission scanning electron microscopy, Transmission electron microscopy, Energy-dispersive x-ray, Temperature Programmed Reduction-H2, N2 Adsorption and Desorption isotherms and Fourier-transform infrared spectroscopy techniques were used to characterize physico-chemical properties of prepared nanocatalysts. The X-ray diffraction results clarified that application of citric acid increased relative crystallinity of Cu and Zn oxides existed in catalyst structure. The Fourier-transform infrared spectroscopy results demonstrated that the zeolite structure was not destroyed after CuO–ZnO–Al2O3/HZSM-5 introduction. The Field emission scanning electron microscopy and Transmission electron microscopy images illustrated that the nanocatalyst synthesized with citric acid has the highest porosity and less population of particle agglomerations. The highest amount of surface area was obtained when citric acid was used as fuel. According to Temperature Programmed Reduction-H2 profiles, the reducibility of nanocatalyst synthesized with citric acid is higher than other samples. The activity of the fabricated nanocatalysts for syngas to Dimethyl ether process were tested at temperature and pressure range of 225–300 °C and 10–40 bar, respectively. Using citric acid as fuel led to achieve greater amount carbon monoxide conversion and Dimethyl ether yield. Furthermore, stability test represented that the activity of this nanocatalyst remained quite stable during 1060 min.

The Influence of Temperature on the Spatial Distribution of AuNPs on a Ceramic Substrate for Biosensing Applications

In this study, we investigated the spatial distribution and homogeneity of gold nanoparticles (AuNPs) on an alumina (Al2O3; AAO) substrate for potential application as surface-enhanced Raman scattering (SERS) sensors. The AuNPs were synthesized through thermal treatment at 450 °C at varying times (5, 15, 30, and 60 min), and their distribution was characterized using field-emission scanning electron microscopy (FE-SEM) and scanning transmission electron microscopy (STEM). The FE-SEM and STEM analyses revealed that the size and interparticle distance of the AuNPs were significantly influenced by the duration of thermal treatment, with shorter times promoting smaller and more closely spaced nanoparticles, and longer times resulting in larger and more dispersed particles. Raman spectroscopy, using Rhodamine 6G (R6G) as a probe molecule, was employed to evaluate the SERS enhancement provided by the AuNPs on the AAO substrate. Raman mapping (5 µm × 5 µm) was conducted on five sections of each sample, demonstrating improved homogeneity in the SERS effect across the substrate. The topological features of the AuNPs before and after R6G incubation were analyzed using atomic force microscopy (AFM), confirming the correlation between a decrease in surface roughness and an increase in R6G adsorption. The reproducibility of the SERS effect was quantified using the maximum intensity deviation (D), which was found to be below 20% for all samples, indicating good reproducibility. Among the tested conditions, the sample synthesized for 15 min exhibited the most favorable characteristics, with the smallest average nanoparticle size and interparticle distance, as well as the most consistent SERS enhancement. These findings suggest that AuNPs on AAO substrates, particularly those synthesized under the optimized condition of 15 min at 450 °C, are promising candidates for use in SERS-based sensors for detecting cancer biomarkers. This could be attributed to temperature propagation promoted at the time of synthesis. The results also provide insights into the influence of thermal treatment on the spatial distribution of AuNPs and their subsequent impact on SERS performance.

Cytocompatible Hyperbranched Polyesters Capable of Altering the Ca2+ Signaling in Neuronal Cells In Vitro.

Synthetic hyperbranched polyesters with potential therapeutic properties were synthesized using the bifunctional polyethylene glycol or PEG with different molecular weights, ca., 4000, 6000, and 20,000 g/mol, and the trifunctional trans-aconitic acid or TAA. During polycondensation, a fixed amount of PEG was allowed to react with varying amounts of TAA (1:1 and 1:3) to control the branching extents. It was found that the synthetic polyesters had a considerable yield and were highly water soluble. Spectroscopic data (Fourier transform infrared and 1H NMR) confirmed the polyester formation; the branching percentages were determined from 1H NMR spectroscopy which varied from 73% to 22% among the synthesized samples. As the molecular weight of PEG was increased, the branching percentage drastically dropped. All polyesters were found to be negatively charged due to the ionization of unreacted -COOH in the branched ends at the working pH (7.4). Both the hydrodynamic size and intrinsic viscosity were found to reduce as the branching extent increased. Among the sets of polyesters, the one with the highest branching percentage (73%) showed the core-shell morphology (evident from field emission scanning electron microscopy and transmission electron microscopy studies). It also exhibited the highest efficiency toward Ca2+ influx in neuronal cells due to the unique morphology and the negatively charged surface. Nevertheless, this particular grade of polyester along with all the other grades was cytocompatible and induced reactive oxygen species generation. Since the maximally branched grade was highly efficient in altering the Ca2+ signaling through stronger influx, it may well be tested for treating neuronal disorders in vivo in future.

Differential interaction modes of As(III)/As(V) with microbial cell membrane induces opposite effects on organic contaminant biodegradation in groundwater

Arsenic, a widespread toxic metalloid in groundwater, derives both from natural geological environment and industrial discharge, is extensively detected to be coexisting with organic contaminants, such as 2,4,6-trichlorophenol (TCP), a prior concerned pollutant. During biological remediation of groundwater, arsenic potentially intervenes microbial behaviors. This study found an opposite interference of arsenic in its two different valences (III and V) on the degradation of TCP by the functional bacteria, Sphingomonas fennica K101. As(III) inhibited TCP degradation in a concentration-dependent manner (from 0.1-10 mg/L), with a maximum inhibition rate of 35.5 %, whereas As(V) exhibited promoting effects by 13.8 % and 33.2 % at 1 mg/L and 10 mg/L, respectively. Employing field emission transmission electron microscopy, quantum chemical calculation, fourier-transform ion cyclotron resonance mass spectrometry and metabolomic analysis, we unveil distinct interactions between cell membranes and arsenic in two valence states. Exposure to As(III) led to significant accumulation of As(III) in the cytoplasm, followed by interaction with intracellular ferritin (ferritin heavy chain 1), releasing iron ions and generating ROS. Subsequently, it induced ferroptosis and disrupted bacterial basal metabolism, thereby inhibiting TCP biodegradation. Oppositely, As(V) bound to a critical component sphingosine and triggered sphingosine polymerization, increasing membrane permeability, which was evidenced by measuring lactate dehydrogenase release. This process facilitated TCP transmembrane permeation by reducing membrane or extracellular secretion resistance. As(V) concurrently upregulated energy metabolism and accelerated TCP degradation. Our study elucidates the influence of prevalent arsenic on biodegradation efficacy, particularly amidst changing redox conditions associated with varying arsenic valences.

Fabrication and characterization of zinc oxide nanorods-modified electrodes using nanoimprint lithography for electrochemical sensing of heavy metal ions

This paper uses the nanoimprint lithography (NIL) technique to present the fabrication and characterization of Zinc oxide nanorods (ZnONRs)-modified electrodes. Characterization of the resulting electrode involved X–ray diffraction, Field Emission Scanning Electron Microscope and Transmission electron microscopy. The electrode surface was modified with ZnONRs using the NIL technique to increase the sensitivity of the electrochemical sensor for detecting small quantities of heavy metal ions, which remain a major concern due to their toxicity and environmental harm. Electrochemical measurements and sensing performance evaluations were conducted to analyze the electrochemical properties and sensitivity of the ZnONRs - modified electrodes. The results demonstrated increased sensitivity towards cadmium ions present in aqueous solutions, and the limit of detection is found to be 20.88 ± 0.9 µM.

Antimicrobial Peptide Octoprohibitin-Encapsulated Chitosan Nanoparticles Enhanced Antibacterial Activity against Acinetobacter baumannii

Background: This study focused on evaluating the physiochemical characteristics and antibacterial activity of Octoprohibitin-encapsulated CNPs (Octoprohibitin-CNPs) against Acinetobacter baumannii. Methods: Octoprohibitin was encapsulated into CNPs via ionotropic gelation with carboxymethyl chitosan (CMC) and low molecular weight chitosan (CS). Octoprohibitin-CNPs were dispersed in phosphate-buffered saline and the release kinetic profile was determined. Then Octoprohibitin-CNPs were examined using field-emission transmission electron microscopy and physicochemical characterization was performed. Antibacterial activity of Octoprohibitin-CNPs against A. baumannii was evaluated. Biofilm inhibition and eradication assays were performed using the crystal violet (CV) staining-based method for biofilm quantification. Results: The average diameter, zeta potential, encapsulation efficiency, and loading capacity of Octoprohibitin-CNPs were 244.5 ± 21.97 nm, +48.57 ± 0.38 mV, and 85.7% and 34.2%, respectively. TEM analysis imaging revealed that Octoprohibitin-CNPs are irregularly shaped, with fewer aggregates than CNPs. Octoprohibitin-CNPs exhibited a biphasic release pattern, characterized by an initial rapid phase followed by a sustained release over time, extending up to 93.68 ± 6.48% total release until 96 h. In vitro, Octoprohibitin-CNPs showed lower cytotoxicity compared to Octoprohibitin alone. Time-kill kinetic and bacterial viability reduction assays showed Octoprohibitin-CNPs exhibited slightly higher antibacterial activity against A. baumannii than Octoprohibitin. Conclusions: Octoprohibitin-CNP-treated A. baumannii exhibited higher levels of morphological deviation, increased membrane permeability, and the production of reactive oxygen species, as well as antibiofilm activity with greater biofilm inhibition and eradication than Octoprohibitin. These findings show that Octoprohibitin-CNPs perform better against A. baumannii compared to Octoprohibitin alone.

Synthesis and characterization of ZnO–NiO binary nanocomposites by hydrothermal technique for gas sensing and photocatalytic applications

Inorganic photocatalytic materials exhibiting a highly efficient response to ultraviolet-visible light spectrum have become a subject of widespread global interest. Nanocomposite metal oxides, particularly Nickel Oxide (NiO) and Zinc Oxide (ZnO), have gained attention for their diverse applications in gas sensing and photocatalytic processes. In this work, ZnO-NiO (ZnO0.6NiO0.4 and ZnO0.4NiO0.6) binary nanocomposites were synthesized by hydrothermal technique. The binary nanocomposites were analyzed by UV-Visible spectrophotometer, X-ray diffraction (XRD), photoluminescence (PL), Fourier transform infrared spectrophotometer (FTIR), energy dispersive X-ray spectroscopy (EDX), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The XRD pattern revealed that the nanocomposites, the peaks of both ZnO and NiO are present indicating the presence of both crystal structures hexagonal wurtzite and cubic. The miller indices, crystallite size, microstrain and dislocation density were determined from the XRD plot. FESEM and TEM analyses showed the spherical morphology of the synthesized composites with an approximate size of 10[Formula: see text]nm. The detailed analysis of ZnO–NiO binary nanocomposite sensor characteristics in terms of sensitivity, selectivity, response and recovery time were carried out and the nanocomposites were found to be highly sensitive to CO2 100 ppm at 350∘C and Cl2 at 200∘C. The photocatalytic degradation outcome showed 52% degradation of methylene blue at 10 ppm and 90[Formula: see text]w/m2. These results suggest the potential utility of these binary nanocomposites in photocatalytic applications for the degradation of organic pollutants.

Zn0.5Ni0.5MnxFe2-xO4 magnetically separable nano ferrite: A highly efficient photocatalyst for environmental remediation

The escalating pollution from industries poses a severe threat to water resources, necessitating efficient photocatalysts for environmental remediation. In this study, we introduce a novel Zn0.5Ni0.5MnxFe2-xO4 nano ferrite, synthesized via sol–gel auto-combustion method. The phase purity of Zn0.5Ni0.5MnxFe2-xO4 nano ferrites was confirmed from X-ray diffraction (XRD) and Fourier Transform Infrared (FTIR) Spectroscopy. The microstructural investigation of nano ferrites was investigated using Field Emission Scanning Electron Microscopy (FESEM) and Transmission Electron Microscopy (TEM). The catalyst’s magnetic properties allow easy separation, addressing the challenge of catalyst retrieval in photocatalysis. Incorporating Zn, Ni, and Mn at tetrahedral and octahedral sites enhances crystallinity, crucial for catalytic efficiency. This mixed metal oxide catalyst demonstrates superior photocatalytic activity, with Zn0.5Ni0.5MnFeO4 exhibiting a remarkable 97% degradation of Reactive Orange (RO) dye under sunlight. Notably, the photocatalyst displays stability and reusability over multiple cycles. The study provides valuable insights into the potential of Zn0.5Ni0.5MnxFe2-xO4 ferrite as a magnetically separable, efficient photocatalyst for environmental remediation.

Biogenic Syntheses of AgNPs With Leaf Extract Abution indicum and Its Application for Antimicrobial and Photocatalytic Activity

ABSTRACTThe biogenic synthesis of silver nanoparticles (AgNPs) with leaf extract Abution indicum was done, and those were characterized by ultraviolet–visible spectroscopy (UV–vis), Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS), powder X‐ray diffraction (PXRD), field emission scanning electron microscopy (FESEM) and transmission electron microscope (TEM) with energy‐dispersive X‐ray (EDX) spectroscopy. The analysis by UV–vis spectroscopy showed a peak of 450 nm, and DLS and zeta potential were utilized to determine the size distribution of the biosynthesized Abution indicum–AgNPs (AI‐AgNPs) with a size range of 24–37 nm, and the X‐ray diffraction peak 38.096o was used to confirm that the crystalline structure of AI‐AgNPs. Furthermore, the antipathogenic effect of synthesized AgNPs and standard antibiotic (Ciprofloxacin) as studied the positive control in different types of bacterial pathogens likes Staphylococcus aureus and Escherichia Coli, with the zone of inhibition values of 9 mm. The synthesized AgNPs displayed excellent photocatalytic activity against reactive blue under sunlight than a UV light irradiation, and maximum degradation of 43% was achieved with 66 min of reaction time. In view of promising activity, the AgNPs could be used photocatalyst for the degradation of dyes in wastewater, and pomegranate leaf extract can be applied as eco‐benign and cost‐effective approach for AgNPs synthesis. Hence, the current findings suggest that Abutilon indicum is a valuable source for tailoring the potential of AgNPs toward various enhanced biological, photocatalytic, and adsorption activities. Consequently, the plant biological molecule‐mediated synthesized AI‐AgNPs could be excellent contenders for future therapeutic applications.

Enhanced performance of hierarchical heterostructures CuS@ZnS-Ag-doped core–shell quantum dots towards photocatalytic degradation of pesticide contaminants in aqueous solution

ABSTRACT In recent years, the pollution of the water by pesticides has become a significant global concern due to the harmful effects these compounds have on human health and the environment. Therefore, removal of pollutants or making them ineffective is necessary for life. In this study, removal of agricultural pesticides such as Deltamethrin, Flumethrin and Phoxim was performed through photodegradation process using CuS@ZnS-Ag quantum dots as photocatalyst. The synthesised CuS@ZnS-Ag heterojunction nanocomposite has suitable charge separation and low electron–hole recombination rate with good optical properties. The synthesised photocatalyst was characterised by various techniques such as X-ray diffraction, Fourier transform infrared spectrometry, UV-Visible spectroscopy, field emission scanning electron microscopy and transmission electron microscopy. The effects of pH, temperature, photocatalyst dose and agitation rate on the degradation were investigated. The optimised conditions were obtained as follows: pH 7 (±0.5), temperature 30 (±2) °C, photocatalyst dose for Flumethrin 30 mg/L, Deltamethrin 10 mg/L and Phoxim 15 mg/mL and agitation rate 500 rpm. Results showed that under optimal conditions, the CuS@ZnS-Ag as photocatalyst can degrade 96% of the pollutants using light-emitting diode lamp. Kinetic studies indicated the pseudo-second-order model.

Fabrication of ZnCo2O4-Zn(OH)2 Microspheres on Carbon Cloth for Photocatalytic Decomposition of Tetracycline.

Zinc cobalt oxide-zinc hydroxide (ZnCo2O4-Zn(OH)2) microspheres were successfully fabricated on carbon cloth via a sample hydrothermal method. The surface morphology of these microspheres and their efficacy in degrading methyl violet were further modulated by varying the thermal annealing temperatures. Adjusting the thermal annealing temperatures was crucial for controlling the porosity of the ZnCo₂O₄-Zn(OH)₂ microspheres, enhancing their photocatalytic performance. Various analytical techniques were utilized to evaluate the physical and chemical properties of the ZnCo2O4-Zn(OH)2 microspheres, including field-emission scanning electron microscopy, energy-dispersive spectroscopy, X-ray diffraction, field-emission transmission electron microscopy, X-ray photoelectron spectroscopy, and UV-vis spectroscopy. Compared to untreated ZnCo2O4-Zn(OH)2 microspheres, those subjected to thermal annealing exhibited increased specific surface area and light absorption capacity, rendering them highly effective photocatalysts under UVC light exposure. Subsequent studies have confirmed the superior performance of ZnCo2O4-Zn(OH)2 microspheres as a reusable photocatalyst for degrading methyl violet and tetracycline. Furthermore, trapping experiments during the photodegradation process using ZnCo₂O₄-Zn(OH)₂ microspheres identified hydroxyl radicals (·OH) and superoxide radicals (·O₂⁻) as the primary reactive species.

Exploring 1T/2H MoS2 Nano Coral Structured Active Electrodes for Enhanced Pseudocapacitive Supercapacitors: A Rigorous Evaluation and Characterization Study

This article optimizes the synthesis parameters of nano coral structured (NC-S) molybdenum disulfide (MoS2) using hydrothermal method and enhances its physiochemical properties for high-performance supercapacitors (SC). This nano coral architecture of transition metal dichalcogenides has garnered significant attention for efficient pseudocapacitive charge storage in SC. Herein, this work demonstrates the fabrication of dual phase MoS2 by tailoring the reaction time of the NC-S. Furthermore, this effect has been explained with the help of several analytical techniques. The synthesized 1T/2H MoS2 NC-S phase was affirmed by powder X-ray diffraction, Raman spectroscopy and X-ray photoelectron spectroscopy studies. The field emission scanning electron microscope and transmission electron microscope images unveiled nano corals like morphology with numerous active sites. Impressively, the as prepared 24, 36 and 48 h MoS2 NC-S entrenched as working electrode endows the achievement with a greater specific capacitance of about 761.82, 1550.86 and 1036.28 F/g at 1 A/g of current density manifests an outstanding rate capability of 94.5, 96.5 and 95.3% capacitive retention even after 1000 cycles. Among them, the 36 h (A-36) synthesized NC-S MoS2 possess high specific energy (43.61 Wh/kg) and power (225.50 W/kg) for this application. Additionally, it demonstrates a commendable capacitive retention of 97% for the two-cell asymmetric setup, even after 5000 cycles at 10 A/g of current density. This inventive configuration of a two-cell device is employed using a Swagelok setup, where the 1T/2H phase MoS2 NC-S//AC exhibit outstanding storage stability and sustained up to 180 sec. The promising results validate that this material can significantly enhance performance in energy storage applications.

Membrane Damage and Metabolic Disruption as the Mechanisms of Linalool against Pseudomonas fragi: An Amino Acid Metabolomics Study.

Pseudomonas fragi (P. fragi) is usually detected in low-temperature meat products, and seriously threatens food safety and human health. Therefore, the study investigated the antibacterial mechanism of linalool against P. fragi from membrane damage and metabolic disruption. Results from field-emission transmission electron microscopy (FETEM) and atomic force microscopy (AFM) showed that linalool damage membrane integrity increases surface shrinkage and roughness. According to Fourier transform infrared (FTIR) spectra results, the components in the membrane underwent significant changes, including nucleic acid leakage, carbohydrate production, protein denaturation and modification, and fatty acid content reduction. The data obtained from amino acid metabolomics indicated that linalool caused excessive synthesis and metabolism of specific amino acids, particularly tryptophan metabolism and arginine biosynthesis. The reduced activities of glucose 6-phosphate dehydrogenase (G6PDH), malate dehydrogenase (MDH), and phosphofructokinase (PFK) suggested that linalool impair the respiratory chain and energy metabolism. Meanwhile, genes encoding the above enzymes were differentially expressed, with pfkB overexpression and zwf and mqo downregulation. Furthermore, molecular docking revealed that linalool can interact with the amino acid residues of G6DPH, MDH and PFK through hydrogen bonds. Therefore, it is hypothesized that the mechanism of linalool against P. fragi may involve cell membrane damage (structure and morphology), disturbance of energy metabolism (TCA cycle, EMP and HMP pathway) and amino acid metabolism (cysteine, glutamic acid and citrulline). These findings contribute to the development of linalool as a promising antibacterial agent in response to the food security challenge.

Biomass extract-mediated preparation of magnesium-doped nickel oxide nanoparticles and their in vitro bioactivities assessment

Biomass extract-mediated fabrication of metal oxide nanoparticles received significant attention in material research because it is eco-friendly, cost-effective, and easy to scalability. Here, the fabrication of Boerhavia diffusa leaf extract (BDE)-mediated magnesium-doped nickel oxide nanoparticles (Mg-doped-NiO-BDE) and their in vitro bioactivities are reported. Several characterization procedures are used to characterize the prepared NiO nanoparticles. Field emission scanning electron microscopy and transmission electron microscopy images exhibit that the Mg-doped-NiO-BDE are distorted spherical. The X-ray diffraction showed that the average crystallite sizes of the nanoparticles are around 51–55 nm. X-ray diffraction, X-ray photoelectron spectroscopy, and energy-dispersive X-ray spectroscopy analysis results confirm that the NiO is produced, and Mg-doping has occurred in the adopted reaction condition. The doped NiO NPs exhibit broad-spectrum antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), as well as antifungal action against Aspergillus niger (A. nigar). The antioxidant, anti-inflammatory, and anti-diabetic efficiencies of doped-NiO NPs (concentration = 400 μg/mL) are around 65 %, 89 %, and 87 %, respectively. The Mg-doped-NiO-BDE nanoparticles show around 75 % viability against the human lung cancer cell line (A459) with a concentration of up to 100 μg/mL, while the IC50 value is 185.6 μg/mL. The scratch test is executed with the mouse fibroblast cells (L929) in which doped-NiO NPs exhibit around 36 % wound-closing ability. The above results signify that the fabricated Mg-doped-NiO-BDE is a potent bioactive material that could be used for biomedical applications.