Field Emission Transmission Electron Microscopy Research Articles

Critical evaluation of silver nanoparticles synthesized at room temperature/microwave irradiation: A green approach

Biological routes of nanoparticle synthesis, especially the use of plant-based extracts, have shown great potential for the production of silver nanoparticles (Ag NPs). Ag NPs synthesized in this way is a simple one-step method that is economical and environmentally friendly. With the increasing need to develop new and effective antibacterial agents, a novel and stable Ag NPs is synthesized using aqueous seed extract of Strychnos potatorum (SP). Ag NPs obtained at room temperature (S1) and under optimal microwave irradiation (S2) were compared in the present work. The as-synthesized Ag NPs are characterized by Ultraviolet-Visible (UV-Vis) spectroscopy, X-Ray Diffraction (XRD), Fourier Transform Infrared (FT-IR) spectroscopy, Field Emission Scanning Electron Microscopy (FESEM) and Transmission Electron Microscopy (TEM). UV-Vis spectra showed Surface Plasmon Resonance (SPR) peaks at 430nm (S1) and 438nm (S2) associated with the formation of Ag NPs. XRD patterns indicate the crystallinity of Ag NPs, with an average crystallite size of approximately 23nm (S1) and 15nm (S2). FT-IR study revealed potential biomolecules to form Ag NPs. FESEM and TEM analysis revealed the spherical shape of Ag NPs. An average particle size of approximately 31nm (S1) and 19nm (S2) was revealed from TEM analysis. To the best of our understanding, this study is novel as Ag NPs synthesized from SP using a microwave oven are described in detail for the first time. The study also demonstrated the potential of Ag NPs for antibacterial effect against Gram-positive bacteria (Streptococcus pneumoniae, Staphylococcus aureus) and Gram-negative bacteria (Klebsiella pneumoniae, Vibrio vulnificus). Our findings show that at a specific concentration, small NPs are more efficient in inhibiting bacterial activity. This research indicates that Ag NPs synthesized from SP exhibit strong antibacterial activity for the treatment of bacterial infection.

Optimization of the Photodegradation of Metoclopramide Drug using Super Nanoparticles in Aqueous Solutions

In the present research carry out to remove pharmaceutical pollutants as a model metoclopramide (MCP) drug from an aqueous medium utilizing a photocatalytic degradation method with super nanoparticles called TiO2 nanoparticles (NP). synthesis of TiO2 nanoparticles by utilizing the hydrothermal processes. The physical characterizations of materials by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), thermogravimetric analysis (TGA), and transmission electron microscope (TEM). The results showed that the efficiency of the TiO2 nanoparticle increased by 88.88%. It also showed that the photocatalytic degradation rate increased with decreasing concentration of MCP drug increasing the intensity of the light led to an increase in the rate of photocatalytic degradation. Study effect of several factors, concentration on the drug, mass of nanoparticle, light intensity that the best conditions for the photocatalytic degradation of 0.3 g of the nanocomposite, MCP drug concentration of 50 m/L, pH solution 8, and light intensity 1.7 mW/Cm2, Thus, the photocatalytic degradation increased with decreasing the concentration of MCP drug. The obtained TiO2 nanoparticle exhibits best photocatalytic degradation than the commercial photo-catalysts TiO2 NPs. Finally, it is essential to evaluate the recycled photocatalytic degradation efficiency, which is one of the utmost significant factors towards photodegradation.

Removal of Amoxicillin Drug from Aqueous Solution by using Marble Powder Surface Activated by Several Acids

In recent years, the problem of the removal drug from wastewater has become one of the most important global problems due to the accumulation of large quantities of drugs on the surface of the water, which causes a lack of penetration of sunlight into water contaminated with drug, and this leads to a reduction in aquatic life forms for all living organisms and also leads to problems large environmental impacts and many dangerous diseases for humans. An attempt was made to prepare an environmentally friendly, economical and available surface that has a high absorption capacity to remove the contaminants of pharmaceuticals such as amoxicillin (AMX) drug. In this study, waste material such as white marble was used as an absorbent material, and its adsorption properties were enhanced and activated by treating it with several acids (HCL, H2SO4, and HNO3). The prepared white marble before and after adsorption were characterized by field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The influence of several parameters like contact time (5–120 minutes), initial concentration of drug (10–50 mg/L), adsorbent dosage (0.02–0.2 g), solution temperature (10–40oC), and pH (2–10) was estimated for adsorption method optimization. The equilibrium adsorption result was examined utilizing the isotherm Langmuir, and isotherm Freundlich models. The attained data indicated that, sorption was found to be fast, 84.44% within 1 hour.

Rapid Semiconducting Supramolecular Mg(II)-Metallohydrogel: Exploring Its Potential in Nonvolatile Resistive Switching Applications and Antiseptic Wound Healing Properties.

An effective strategy was employed for the rapid development of a supramolecular metallohydrogel of Mg(II) ion (i.e., Mg@PEHA) using pentaethylenehexamine (PEHA) as a low-molecular-weight gelator in aqueous medium under ambient conditions. The mechanical stability of the synthesized Mg@PEHA metallohydrogel was characterized by using rheological analysis, which showed its robustness across different angular frequencies and oscillator stress levels. The metallohydrogel exhibited excellent thixotropic behavior, which signifies that Mg@PEHA has a self-healing nature. Field emission scanning electron microscopy and transmission electron microscopy images were utilized to explore the rectangular pebble-like hierarchical network of the Mg@PEHA metallohydrogel. Elemental mapping through energy-dispersive X-ray spectroscopy analysis confirmed the presence of primary chemical constituents in the metallohydrogel. Fourier transform infrared spectroscopy spectroscopy provided insights into the possible formation strategy of the metallohydrogel. In this work, Schottky diode structures in a metal-semiconductor-metal geometry based on a magnesium(II) metallohydrogel (Mg@PEHA) were constructed, and the charge transport behavior was observed. Additionally, a resistive random access memory (RRAM) device was developed using Mg@PEHA, which displayed bipolar resistive switching behavior at room temperature. The researchers investigated the switching mechanism, which involved the formation or rupture of conduction filaments, to gain insights into the resistive switching process. The RRAM device demonstrated excellent performance with a high ON/OFF ratio of approximately 100 and remarkable endurance of over 5000 switching cycles. RRAM devices exhibit good endurance, meaning they can endure a large number of read and write cycles without significant degradation in performance. RRAM devices have shown promising reliability in terms of long-term performance and stability, making them suitable for critical applications that require reliable memory solutions. Significant inhibitory activity against the drug-resistant Klebsiella pneumonia strain and its biofilm formation ability was demonstrated by Mg@PEHA. The minimum inhibitory concentration value of the metallohydrogel was determined to be 3 mg/mL when it was dissolved in 1% DMSO. To study the antibiofilm activity, an MTT assay was performed, revealing that biofilm inhibition (60%) commenced at 1 mg/mL of Mg@PEHA when dissolved in 1% DMSO. Moreover, in the mouse excisional wound model, Mg@PEHA played a crucial role in preventing postoperative wound infections and promoting wound healing.

Green synthesis of silver nanoparticles using Saccharum officinarum leaf extract for antiviral paint

Abstract In this study, silver nanoparticles (AgNPs) were synthesized via an eco-friendly approach using an extract from sugarcane leaves (Saccharum officinarum). The optimal synthesis conditions were determined to be a pH of 10, yielding AgNPs with an average size of 11.7 ± 2.8 nm. This was substantiated by UV-vis spectral analysis, transmission electron microscopy, and field emission transmission electron microscope coupling with selected area electron diffraction. The synthesized AgNPs exhibited notable antibacterial efficacy against two prominent pathogens, namely Staphylococcus aureus and Escherichia coli, with minimum inhibitory concentration values of 20 and 2.5 ppm, respectively. Further extending the applications of AgNPs, they were successfully integrated into architectural paints at varying concentrations to create antiviral coatings. The addition of AgNPs influenced several properties of the paints, including viscosity, hiding power, and color characteristics. Notably, our findings revealed that the antiviral paint containing 80 ppm of AgNPs effectively hindered virus propagation, exhibiting a remarkable reduction of over 90% when compared to the control, measured by 50% tissue culture infectious dose.

Interweaved needle‐shaped α‐Ni(OH)2 nanoparticles adorned on graphene oxide: A new class of heterogeneous catalysts for α‐alkylation of ketones and synthesis of azines

A simple approach for synthesizing needle‐shaped α‐Ni(OH)2 nanoparticles adorned on graphene oxide, α‐Ni(OH)2‐GO, is described. The nanocomposite was isolated as an air‐stable black powder and characterized by various instrumental techniques. The interweaved needle‐shaped morphology and the average particle diameter ~7 nm of the adorned α‐Ni(OH)2 nanoparticles were ascertained by Field Emission Scanning Electron Microscopy (FESEM) and Transmission Electron Microscopy (TEM) analysis, respectively. The catalytic potential of the nanocomposite was scrutinized in the synthesis of monosubstituted ketones via a hydrogen autotransfer strategy and synthesis of azines via dehydrogenative pathway. The products of both reactions were isolated in excellent yields and characterized by nuclear magnetic resonance (NMR) spectroscopy. α‐Ni(OH)2‐GO could be segregated and recycled for up to five cycles. The operational simplicity, broad substrate scope, non‐toxic side products, recyclability, and superior catalytic potential of the catalyst are some of the remarkable features of this protocol.

Al2O3-based hybrid composite coatings for mitigating the slurry erosion of an advanced steel in saline and non-saline environments

The present work focuses on the comparative slurry erosion performance evaluation of an advanced steel (ASME SA387) and the alumina-based hybrid coatings for such steels. The study aims to investigate the effect of coatings' properties on their erosion-corrosion behaviour to comprehend their wear performance in saline and non-saline environments. The coatings have been developed by the highly efficient high-velocity oxygen-fuel (HVOF) process. The alumina matrix is reinforced with ceria (CeO2), and hexagonal boron nitride(hBN). A detailed investigation starts with analyzing the coatings' mechanical properties at surface, subsurface and interface regions by using nanoindentation technique, followed by the slurry erosion performance evaluation. To get an in-depth understanding of the materials' performances, various metallurgical characterization techniques like X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), and field emission transmission electron microscopy (FESEM) are used. In saline environments, all the materials eroded more when compared to those in non-saline environments. Corrosion-assisted erosion mechanism is found to be the predominant cause of the higher erosion rates in saline slurry medium. Among the coatings, splat detachment and pitting were found to be the erosive wear mechanisms at 30° and 90° slurry flow directions, respectively. However, erosion reduction of ≈ 90 % at 30° impact angle and ≈ 76 % at 90° impact angles were observed for alumina coatings with 0.8 wt% ceria, and 3 wt% hBN additions when compared to the substrate in the saline environments. The observed results were attributed to the metallurgical enhancements in the form of second phases in the coating microstructure, and the mechanical properties at the surface, subsurface, and interface regions.

Effect of trace bismuth on the solidification structure of hypereutectic Al–22Si alloys

The effect of trace Bi on the solidification structure of the Al–22Si alloy was studied by optical microscopy, scanning electron microscopy, field emission transmission electron microscopy, X-ray diffraction, and differential scanning calorimetry. Trace amounts of Bi were found to have an inhibitory effect on the growth of primary silicon in the Al–22Si alloy. The average size and area fraction of primary silicon reached a minimum when 0.05 wt% Bi was added. As the bismuth content gradually increased, the average size and area fraction of primary silicon continued to increase. The addition of Bi improved the morphology of eutectic silicon in the Al–22Si alloy, as it gradually changed from long needle flakes to short needle flakes. Stacking faults formed in eutectic silicon may have resulted in its morphogenesis.

Semiconductive (Cu–S)n Metal–Organic Frameworks Hybrid Polyaniline Nanocomposites as Hydrogen Sulfide Gas Sensor

A semiconductive (Cu–S)n metal–organic framework (MOF) incorporated polyaniline (PANI) nanocomposite was applied for hydrogen sulfide (H2S) gas sensing. The (Cu–S)n MOF nanosheets were successfully synthesized using a one-pot reflux method. First, fiber-like (Cu–S)n MOF/ PANI nanocomposites were prepared through an in situ oxidative polymerization. As evaluated by field-emission transmission electron microscopy (FE-TEM), the nanosized spherical (Cu–S)n MOF particles were well-distributed in the fiber matrix. Then, the nanocomposite was spin-coated onto an interdigitated electrode (IDE) for H2S gas sensing, displaying high sensitivity, selectivity, repeatability, and stability similar to pure PANI. As a result, 3wt% (Cu–S)n MOF/ PANI nanocomposite showed the best performance for H2S detection. The mechanism for improving H2S sensing performance might be attributed to the conductive composite networks' significantly enhanced conductivity and increased doping sites of the (Cu–S)n MOF. In addition, the energy band gaps of PANI-based nanocomposites were optimized by the incorporated (Cu–S)n MOF, indicating the successful hybridization of energy levels between inorganic MOF and organic PANI. This study first demonstrates semiconductive MOF-PANI-based nanocomposites for H2S gas sensing.

Graphene nanoplatelets anchored into Ag doped spinel CoFe2O4 nanohybrid: Synthesis, structural, electrical, superior dielectric and room temperature induced ferromagnetism performance for high frequency device application

Graphene (GnPs) incorporated Ag-CoFe2O4 nanocomposite was synthesized using a simple solvothermal method using green synthesis method by okra plant extract. The prepared materials were micro-analyzed by X-ray diffraction (XRD) measurements, Fourier transform-infrared (FT-IR) spectra, Field emission scanning electron microscope (FESEM) and transmission electron microscopy (TEM) microanalysis. The average particle size obtained from XRD data was calculated to be 32.6 nm for Ag- CFO nanoparticles and 24 nm for GnPs doped Ag- CFO nanocomposite which was in good agreement with the particle size (in nm) estimated from the FESEM and TEM micrographs. The effective charge carriers transfer from the from Ag- CFO nanoferrites to graphene pallets and in case of GnPs incorporated Ag- CFO nanocomposite and the long-drawn-out recombination of electron–hole pairs were evidently shown by means of room temperature PL measurements. The photocurrent values well support the PL measurements signifying transfer of the electron-hole pairs. Light dependent Electrochemical Impedance Spectroscopy indicates the incidence of a light dependent dielectric relaxation phenomenon. Massive dielectric values with low loss suggest the GnPs doped nanohybrid to be well suited for high frequency device application. Interestingly, incorporation of GnPs alters the electronic configuration of the nanocomposites inducing ferromagnetic interaction.

PH-controlled synthesis of ZnO nanoflowers: A correlation study among the optoelectronic properties and improved photodegradation efficiency

ZnO nanoflowers (ZF) were successfully synthesized by a simple pH-controlled co-precipitation technique. Systematic investigations such as X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM) and Transmission Electron Microscopy (TEM) were carried out to confirm the structure and morphology of the sample. It has been found that the petals of the nanoflowers are composed of nanorods. The higher Urbach tail energy calculated from the optical absorbance spectrum indicates the presence of structural defects in the sample. The findings confirmed that the photoluminescence (PL), photoconductivity and photocatalytic characteristics of ZnO are inextricably linked to oxygen defects. The presence of oxygen vacancy (Ov) and surface adsorbed oxygen in the sample is confirmed by X-ray Photoelectron Spectroscopy (XPS), PL, Fourier Transform Infrared Spectroscopy (FTIR) and Raman Spectroscopy. Also, it shows an improved photocatalytic efficiency with Rhodamine B (RhB) dye under UV (100%, 25 min) and visible (98%, 60 min) light irradiation. The higher Förster Resonance Energy Transfer (FRET) between the ZF and RhB dye can have a significant role in the photocatalytic activity of ZnO. Also, the results confirm that the stronger the PL signal, the lesser the photocatalytic activity, because of the rapid recombination of photo-induced electrons and holes. The higher photocatalytic efficiency of ZF results from O-related defects such as Ov and surface adsorbed groups in the sample.

Multifaceted applications of chitosan-L-ornithine modified ZnO nanoparticles: Antibacterial, antioxidant, and anticancer potentials

Developing polymeric inorganic nanoparticle-based nanomedicines has significantly advanced antibacterial and anticancer treatments. These innovative agents have attracted significant attention due to their unique physicochemical properties and promising efficacy in targeting bacteria and cancer cells. The primary objective of this study is to investigate the synthesis of chitosan and l-ornithine-supported zinc oxide nanoparticles (ZnCsLO NPs) to assess their biological effects. The X-ray diffraction (XRD) pattern confirmed the synthesis of ZnO and ZnCsLO NPs, with wurtzite hexagonal structure. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) showed nano-flake and polygonal structures for ZnO and ZnCsLO NPs, respectively. Fourier transform infrared (FTIR) spectroscopy of ZnO and ZnCsLO NPs revealed characteristic peaks such as ZnO, chitosan, and l-ornithine molecules. The photoluminescence (PL) spectra of ZnO and ZnCsLO NPs displayed green emission peaks at 519 nm and 527 nm respectively, attributed to oxygen vacancies and inherent defects. The antibacterial activity was tested against various Gram-positive and Gram-negative bacterial strains using the well diffusion method. The ZnCsLO NPs exhibited higher antibacterial activity than ZnO NPs. In terms of antioxidant activity, ZnCsLO NPs exhibited the highest scavenging activity compared to ZnO NPs against DPPH. The anticancer activity of ZnO and ZnCsLO NPs was tested against the breast cancer cell line MDA-MB-231, where ZnCsLO NPs exhibited higher anticancer activity than ZnO NPs. Toxicity studies of ZnCsLO NPs on human fibroblast L929 showed less harmful effect on healthy cells compared to ZnO. Based on the findings of this research, there is a strong indication that ZnCsLO NPs hold great potential as a nanomaterial well-suited for advanced biomedical industrial applications.

Study on the nano-structure characteristics of particle before and after diesel oxidation catalyst for diesel engines

ABSTRACT Diesel Oxidation Catalyst (DOC) is the most important and advanced part of the after-treatment technology route. After the exhaust passes through DOC, CO, and HC will be significantly reduced, while particles are mainly captured by the Diesel Particulate Filter (DPF) device behind. In order to further investigate the effect of DOC on the nano-structure characteristics of diesel emission particles. The particles before and after DOC of 186FA diesel engine at 2700 r/min, 100% load, and 3600 r/min, 100% load are collected. The nano-structure characteristics of particles are investigated using field emission transmission electron microscopy (FETEM) combined with small angle X-ray scattering radiation technique (SAXS). Based on FETEM and SAXS analysis of particles, a nano-scale particle spatial structure model including particle size, pores, and visual boundary layer is proposed. The results show that the average radius, interface layer thickness, and fractal dimension of the particles are reduced after the DOC. In contrast, the specific surface area of the particles is increased after the DOC. At 3600 r/min 100% load, the average radius is reduced from 23.3 to 21.5 nm, accounting for 7.8%. Interface layer thickness is reduced from 13.3 to 12.9 nm. The specific surface area of the particles is increased from 0.146 to 0.166 m2/mm3. The research results provide a theoretical basis for the regeneration and oxidation of particles in DPF.

Microstructural characterization of AM60- TixNby nanocomposite powders processed by high-energy ball milling

Magnesium alloys are one of the lightest metal alloys and are considered potential candidates for structural and hydrogen storage applications. High-energy ball milling is an efficient powder metallurgy technique to produce fine composite particles. The AM60 Magnesium alloy was ball milled with different reinforcement concentrations (5Nb,10Nb, 5Ti,10Ti, 3Ti+7Nb, and 3Nb+7Ti) wt% for 10 h and 20 h. The morphology and microstructure were analyzed using a scanning electron microscope equipped with energy dispersive spectrometry and field emission transmission electron microscope. The crystallite size, lattice strain, and solid solubility were analyzed using XRD. It was observed that higher milling time has refined the particle size. The XRD analysis revealed that a maximum crystallite size of 17 nm was observed in the AM60Ti10 composite after 10 h and a minimum of 14 nm in the AM60Ti3Nb7 composite after 20 h milling time. The results revealed that niobium and titanium reduced the crystallite size and enhanced the lattice strain synergistically. The maximum lattice strain (0.066 %) and dislocation density (9 nm−2) were observed in the AM60Nb7Ti3 composite after 20 h milling time. The SEM results revealed The AM60Nb10 composite after 20 h presents a minimum particle size of (9 μm), while AM60Ti5 has a maximum particle size of 15 μm after 10 h milling. The Ti addition causes agglomeration and the AM60Ti5 composite has the maximum average particle size of 15 μm after 10 h milling. The SEM results revealed that flattened agglomerates are formed as the result of higher milling energy during the collision.

Monodispersed AuNPs synthesized in a bio-based route for ultra selective colorimetric determination of Ni(II) ions

Nanoparticle (NP) systems with controllable and adjustable response sensor characteristics are promising for the colorimetric sensing of heavy metal ions in aqueous systems. In this article, uniform gold nanoparticles (AuNPs) with a mean diameter of 31.16 ± 6.67 nm have been achieved with the inexpensive and easily affordable differential centrifugation technique. Thereafter, they are deployed for Ni(II) ions colorimetric determination. Plant phytochemicals (mostly GC, EGC, CG and ECG polyphenols) that exist as natural reducing agents in mature green tea leaves were explored for the synthesized AuNPs. Subsequently, various spectroscopic and imaging methods such as UV–Vis spectroscopy, X-ray diffractometer (XRD), field emission transmission electron microscopy (FETEM), and X-ray photoelectron spectroscopy (XPS) have been applied for a greater insight into the morphological and structural characteristics of the green method synthesized AuNPs. The colorimetric sensing ability of the AuNPs for Ni(II) ionic identification in aqueous tap water system (0.001 to 1 mg/L) has been quantified in terms of the limit of detection (LOD) and limit of quantification (LOQ) values of 0.001 and 0.005 mg/L respectively. Furthermore, the metal-ligand interaction between AuNPs and Ni(II) ions resulted in a noticeable shift in color, and from the pink (λmax= 528 nm) to purple hue (λmax= 556 nm). The FETEM analysis assured clustering tendencies of AuNPs upon exposure to Ni(II) ions. The XPS analysis conveyed the coordination of positively charged Ni(II) ions with the surface-bound negative charged functional groups (–OH, C = O) of the AuNPs. These findings confirmed the practical relevance of the AuNPs for application as a potential colorimetric sensory system.

Application of Taguchi method to optimize the properties of cobalt ferrite nanoparticles doped by Ca2+ and Gd3+

This study investigates the influence of Ca2+ and Gd3+ doping, coupled with crucial processing parameters on the properties of cobalt ferrite nanoparticles synthesized through the sol-gel auto-combustion method. A systematic exploration of these multifaceted effects was conducted using an L25 orthogonal array of the Taguchi method, facilitating the optimization of these parameters. X-ray diffraction (XRD) was utilized in conjunction with Rietveld refinement analysis to discern the structural properties and cation distribution present in the synthesized samples. This investigation yielded cobalt ferrite nanoparticles with an average crystallite size from 9 to 65 nm. Moreover, the microstructural analysis conducted using field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) demonstrated a significant influence of these parameters on the morphology and average grain size of the nanoparticles. Magnetic investigations revealed that saturation magnetization values varying from 44.94 to 89.92 emu/g. Remarkably, the Taguchi method optimized the synthesis conditions, establishing Ca2+ and Gd3+ doping concentrations of 0.032 and 0.03, pH at 6, a calcination time of 4 h, and a temperature of 800 °C. These settings yielded a sample exhibiting a uniform particle distribution and homogeneous morphology, marking it as a promising prospect for applications in the realm of biomedicine.

Nanostructural Design of ZnO Using an Agro-Waste Extract for a Sustainable Process and Its Photocatalytic Activity.

The use of agro-waste extracts (AWEs) as a sustainable medium for developing cost-effective and ecologically friendly nanomaterials has piqued the interest of current researchers. Herein, waste extracts from papaya barks, banana peels, thumba plants, and snail shells were used for synthesizing ZnO nanostructures via a hydrothermal method, followed by calcination at 400 °C. The crystallinity and pure wurtzite phase formation of ZnO nanostructures were confirmed via X-ray diffraction. ZnO nanostructures with various morphologies such as tight sheet-like, spherical, porous sheet-like, and bracket-shaped, comprising small interconnected particles with a highly catalytically active exposed (0001) facet, were observed via field emission scanning electron microscopy and transmission electron microscopy. The formation mechanism of the various morphologies of the ZnO nanostructures was proposed. Ultraviolet-visible spectra showed different absorption band edges of ZnO nanostructures with a bandgap in the range of 3.17-3.27 eV. Photoluminescence studies showed the presence of various defect states such as oxygen and zinc vacancies and oxygen and zinc interstitials on ZnO nanostructures, which are usually observed in traditionally prepared ZnO. The photocatalytic activity of ZnO nanostructures was evaluated under direct sunlight using rhodamine B (RhB) and Congo red (CR) dyes as probe pollutants. Furthermore, prepared ZnO nanostructures could potentially adsorb anionic dyes (e.g., CR) in the absence of light. Superoxide and hydroxide radicals played a vital role in the photocatalytic activity of ZnO. The photocatalyst could be reused for up to three cycles, indicating its stability. Therefore, this study reports the diverse use of AWEs as cost-effective media for nanomaterial synthesis.

Multifaceted characterization of a Zn0.9Ca0.1Fe2O4/CeO2/NiFe2O4 nanocomposite electrode for battery-type supercapacitors

The majority of current energy application research is focused on the development of electrode materials for high-power devices. We investigated the electrochemical properties of a Zn0.9Ca0.1Fe2O4/CeO2/NiFe2O4 nanocomposite. The crystallographic characteristics of the produced nanocomposite were studied using X-ray diffraction (XRD). The structure of the material was confirmed using field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). Fourier transform infrared electron spectroscopy (FT-IR) analysis found two distinct vibrational bands at 699.65 and 545.02 cm−1, which can be attributed to metal-oxygen bond stretching in both tetrahedral and octahedral configurations. Magnetic measurements were done at room temperature using a vibrating sample magnetometer (VSM), and the magnetic behavior of the nanocomposite was found to be 33.82 emu/g. The results demonstrated battery-like behavior, with a specific capacity (Cs) of 266.7 C g−1 at 1 A/g. Notably, the prepared electrode had a significant capacity retention of 90 % even after 5000 cycles. These findings emphasize the nanocomposite's potential for a wide range of energy storage applications.

Magnetically separable electrospun BiFeO3/BiVO4 heterojunction nanofibers and the visible-light photocatalytic performance

In this paper, a novel architecture of magnetically separable BiFeO3 nanofibers were prepared by electrospinning method, and BiFeO3/BiVO4 heterojunction photocatalyst was successfully synthesized by hydrothermal method. Their structures and optical properties were characterized by X-ray diffraction, scanning electron microscopy, field emission transmission electron microscopy, the Brunner-Emmett-Teller surface areas, X-ray photoelectron spectroscopy, vibrating sample magnetometer, photoluminescence spectrum and UV–visible absorption spectroscopy. The degradation of rhodamine B by visible light irradiation for 180 min showed that the molar ratio of BiFeO3:BiVO4 was 2:1, which showed higher photocatalytic performance. The high surface area of BiFeO3:BiVO4 nanofiber heterojunction may provide more active sites for the photocatalytic reaction and promote the spatial separation of photogenerated charge, and thus show higher visible light catalytic efficiency, which is 9.5 times and 3.6 times of the single component of BiFeO3 and BiVO4 respectively. In addition, BiFeO3:BiVO4 heterojunction nanofibers are ferromagnetic and can be separated from solutions under external magnetic fields. The photocatalytic activity of the BiFeO3:BiVO4 heterojunction did not decrease significantly after five catalytic experiments, indicating that BiFeO3:BiVO4 heterojunction is stable. Free radical capture experiments show that ·OH and h+ were the main groups involved in redox reactions. Proposed photocatalyst can efficiently degrade environmental pollutants Rhodamine B under visible-light, and is easy to recover, which is expected to be used in industrial wastewater treatment.

Synthesis, Characterization, and Application of TiO2 Nanorods for Hydrazine Sensing

This paper presents a comprehensive investigation into the synthesis, characterization, and application of titanium dioxide (TiO2) nanorods for the purpose of hydrazine chemical sensing. The nanorods were efficiently prepared through a low-temperature chemical synthesis process, and a detail characterization process was undertaken to assess their structural, morphological, compositional, and sensing properties. Employing sophisticated techniques such as field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM), the morphological characterizations unveiled a high-density growth of diminutive nanorods. Crystallographic examinations confirmed the exceptional crystallinity of the synthesized nanorods, showcasing a predominant anatase phase. These insights into the structural and morphological attributes contribute to a profound understanding of the nanorods’ potential in various applications. Notably, this study focuses on the utilization of TiO2 nanorods as electron mediating materials for the fabrication of a hydrazine chemical sensor. The fabricated sensor exhibited commendable sensitivity, registering a current response of 4.69 μA·μM−1·cm−2, coupled with a remarkably low detection limit of 174 μM. The outcomes of this investigation underscore the promising role of TiO2 nanorods as effective electron mediators in chemical sensor design. This work establishes a foundation for the development of sensors capable of detecting a spectrum of hazardous and toxic chemicals, with a specific emphasis on hydrazine.