In this study, copper oxide nanoparticles (CuO NPs), zinc oxide nanoparticles (ZnO NPs), and copper oxide/zinc oxide nanocomposites (CuO@ZnO NPs) were synthesized by green synthetic route where bioactive compounds inherently present in the leaf extract of Artemisia vulgaris act as stabilizing and reducing agents. Phytochemicals present in leaf extract were assessed by qualitative chemical tests and spectroscopic measurements. UV-visible spectroscopy, Fourier Transform Infrared (FTIR) spectroscopy, Energy Dispersive X-ray (EDX) spectroscopy, X-ray Diffraction (XRD), and Field Emission Scanning Electron Microscopy (FESEM) were used to characterize the as-synthesized nanomaterials, i.e., CuO, ZnO, and CuO@ZnO NPs. XRD pattern revealed the crystalline nature of nanoparticles. Based on the Debye–Scherrer formula, the sizes of CuO NPs, ZnO NPs, and CuO@ZnO NCs were found to be 17.24, 20.74, and 22.50 nm, respectively. The band gap of the as-prepared nanomaterials was measured using the Tauc plot. Using the nanomaterials, MB degradation was studied at room temperature under exposure to UV light. The degradation efficiency of CuO, ZnO, and 2% CuO@ZnO was found to be 52%, 68%, and 98%, respectively. Kinetic degradation process reveals that the CuO@ZnO NCs showed a better photocatalytic activity on MB dye with the degradation constant of 0.04124 min−1 compared to those of either constituent. Based on the findings, it was found that CuO@ZnO nanocomposites have the potential to degrade MB as an organic dye and can be used for wastewater treatment.

Biological synthesis of nanoparticles (NPs) using alfalfa (Medicago sativa L.) and other plants has several advantages such as lower costs, reduction of pollution, and improvement of the environment and human health. Often, biosynthesis is used to synthesize Ag, Au, and ZnO NPs. Less often are also synthesized Cu and Fe NPs. Synthesis with plant extracts from their parts or callus cultures is a widely used method since extracts contain the most significant number of biomolecules. Synthesis with living plants (in vivo) provides NPs with improved properties for better interactions with plants but is used less often due to the long realization time, the need to control the plants’ growing conditions, and difficulty in controlling the size and shape of the synthesized NPs. Here, we performed a systematic review of various methods for the biological synthesis of different metal NPs with different plants, to highlight advantages and disadvantages of mentioned methods. For discussion, results showed that biosynthesis of NPs allows obtaining NPs with reduced toxicity, and their size and shape depend on the type and number of biomolecules present in plants. Plant biomolecules determine the antibacterial and anticancer properties of NPs, as well as increasing the use of NPs in biomedicine, for better drug transport, therefore medicinal plants or sea plants are mostly used for biosynthesis. NPs which were synthesized in marine plants could be a very effective agent against water bacteria; therefore, if NP biosynthesis takes place in water, biological water purification is possible. Limitations of the study included a great methodological diversity of the synthesis, it is still difficult to systematize the synthesis methods, and it seems that each described study uses a different synthesis protocol; therefore, in future studies, it is necessary to clarify which method can provide the most efficient biosynthesis and develop a unified approach.

Herein, we report on a fluorine-doped single-walled carbon nanotube (FSWCNT) phenomenon, that yields tunable high-frequency self-sustained acoustoelectric direct current (ADC) oscillations. A tractable analytical method was used in the hypersound domain, to base the calculations on carriers in the lowest miniband. Hypothetically, the energy of interaction between the carriers and the acoustic phonons is less than the energy of the typical carriers. High-order harmonics of the acoustic phonons’ effective field could be disregarded under this supposition. The ADC was observed to exhibit a nonlinearity, that resulted from the carrier distribution function’s distortion as a result of interaction with the acoustic phonons, which had strong nonlinear effects. Theoretically, we demonstrated that the dynamics of space charge instabilities, due to Bragg reflection of Bloch oscillating carriers in the FSWCNT’s miniband, were the only factors which contributed to the creation of radiation in the terahertz (THz) frequency range. The study also investigated the influence of various FSWCNT parameters such as the overlapping integrals (Δs and Δz), ac-field E1, and carrier concentration noon the behaviour of the ADC. The results showed that the intensity of the ADC oscillation Jzzae/Joae could be tuned by adjusting Δs, Δz, E1, and no.This tunability suggests that FSWCNTs could be used as an active device operating at very high frequencies, potentially reaching the submillimeter wavelength range. The study also suggests the possibility of domain suppression and acoustic Bloch gain through dynamic ADC stabilisation.

The presence of emerging contaminants in wastewater like tetracycline poses a significant challenge in water reuse worldwide. The implementation of a p-n heterojunction and dye-sensitized techniques in the enhancement of graphite carbon nitride provides a promising alternative for visible light-driven degradation of emerging contaminants present in wastewater. The present study investigated dye-sensitized and plain composites in degrading tetracycline using natural sunlight in a parabolic trough reactor. The study synthesized four composites of ZnFe2O4-g-C3N4 at 5, 15, and 25 wt% loading of the ferrite by direct annealing of melamine, followed by thermal and ultrasonic exfoliation of bulk graphite carbon nitride and in situ precipitation with zinc ferrites to yield a composite photocatalyst. The photocatalysts were characterized using X-ray diffraction (XRD) analyses which confirmed that all the spinel ferrite phases of ZnFe2O4 were well bonded with g-C3N4 nanosheets to form a composite. The crystallite sizes were calculated by the Debye–Scherrer equation indicating crystal sizes of between 4.63 and 8.61 nm confirming the nanostructures. The scanning electron microscope-energy dispersive spectroscopy (SEM-EDX) tests verified that the spherical globules of ZnFe2O4 were well attached to the mesoporous layers of g-C3N4 and absence of contaminant phases. The UV-Vis analysis for 25% ZF-GCN revealed a band gap reduction from 2.67 eV to 2.03 eV. The PL intensity for all the composites decreased at excitation of 266 nm and 550 nm which was evidence for suppressed charge recombination. A 25% ferrite loading resulted in the best photocatalytic performance with tetracycline degradation of 93.64% and total organic carbon (TOC) removal of 51.89%. The sensitization of the 25% ZF-GCN composite with Eosin Y further improved its performance for degradation of tetracycline to 94.62% and TOC removal to 68.29%. Therefore, dye sensitization is an efficient way of improving the photocatalytic activity of a multicomponent photocatalyst for the removal of emerging pollutants.

Cesium lead bromide (CsPbBr3) nanocrystals exhibit remarkable optoelectronic properties and exceptional stability. As a result, they have garnered significant interest for their potential applications in various fields, including solar cells, light-emitting devices, photodetectors, and lasers. Despite its resistance to moisture, oxygen, and heat compared to other perovskite materials, CsPbBr3 still faces challenges maintaining its structural and optical stability over extended periods. This study proposes a robust solution to enhance and improve simultaneously the photoluminescence intensity and stability of CsPbBr3 nanocrystals. The solution involves doping the perovskite precursor with green-synthesized carbon quantum dots (CQDs) and tri-n-octyl phosphine (TOP). The results indicate that the photoluminescence intensity of the perovskite nanocrystals (NCs) is sensitive to varying CQD ratios. A high photoluminescence intensity enhancement of 45% was achieved at the optimal CQDs ratio. The synthesized perovskite NCs/CQDs also demonstrated improved stability by adding TOP into the mixture. After storage in the air for 45 days, the mixed perovskite NCs maintained their performance, which was almost unchanged. Solar cell devices based on the modified perovskite NCs showed a power conversion of 7.74%. The devices also demonstrated a significant open-circuit voltage (VOC), with the most successful device achieving a VOC of 1.193 V, an Isc of 10.5748 mA cm−2, and a fill factor (FF) of 61%. This study introduces a cost-effective method for producing high-quality all-inorganic optoelectronic devices with enhanced performance and stability.

The dissolution of manganese and its deposition on the anode surface cause poor cycling stability in lithium-ion batteries. To alleviate these issues, this study probes the electrochemical activity of highly crystalline and cation-adjusted lithium manganese oxide (LMO) carbon spinel composite obtained via a modified sol-gel synthesis procedure. The pristine LMO cathode was functionalized with a Fe and Mg alloy and fused with purified multiwalled carbon nanotubes (MWCNTs) to form a catalytically stabilized LiMn1.98Fe0.01Mg0.01O4/MWCNT (LMO-FeMg/MWCNT) framework. High-resolution SEM analysis showed well-dispersed particles in the nanometer size range. The electrochemical characteristics of the novel composite materials yielded favourable electrochemical results with diffusion coefficients of 1.91 × 10−9 cm2·s−1 and 5.83 × 10−10 cm2·s−1 for LMO-FeMg and LMO-FeMg/MWCNT, respectively. This improvement was supported by impedance studies which showed a considerable Rct reduction of 0.27 Ω and 0.71 Ω. The cation stabilized system outperformed the pristine LMO material with specific capacities around 145 mAh·g−1, due to an enhancement in electrochemical activity and structural stability.

This work focuses on utilizing the X‐ray diffraction technique as an alternative method to specialized and high‐cost techniques such as X‐ray photoelectron spectroscopy to obtain the cation distribution in magnetic nanoparticles as MFe2O4 with spinel structure synthesized by thermal decomposition. X‐ray diffraction measurements for MFe2O4 with M = Co2+ as transition cation (inverse spinel CoFe2O4) showed sensitivity to the cation distribution for octahedral and tetrahedral sites in this material with this kind of crystalline structure, being a good option for its determination. The cation distribution was obtained from the X‐ray diffraction intensity ratios for the most sensitive crystalline planes to the cations in octahedral and tetrahedral sites. Besides, the Debye–Scherrer equation and line profile analysis method from the diffraction pattern were used to determine the size distribution and the crystallite size. The size distribution obtained by X‐ray diffraction was from 15 to 18 nm, while transmission electron microscopy was found to be from 10 to 25 nm. The inversion degree x derived from X‐ray diffraction exhibits variability within the interval 0.6 < x < 0.8, not very far from that obtained by X‐ray photoelectron spectroscopy (x = 0.67). This material exhibits a saturation magnetization of 124.88 emu g−1. Consequently, the X‐ray diffraction technique opens the possibility of obtaining reliable information related to nanoparticles’ morphological and chemical properties with spinel structure.

The growing demand for energy storage has drawn considerable attention to devices such as supercapacitors, which currently lack high energy density but depict high power density and long cycle life. In this work, we have synthesized La0.3Sr0.7Ti0.5Fe0.5O3 (LSTF) nanoparticles and Ti3C2‐MXene‐modified LSTF nanoparticle hybrid to study the effect of MXene on electrochemical properties of the nanoparticles. The X‐ray diffraction (XRD) and Raman spectroscopy analysis showed that the hybrid structure retained all the major peaks of the nanoparticles and the MXene, which showed its successful synthesis. The morphological analysis was done utilizing scanning electron microscopy (SEM), which verified that the nanoparticles had been adsorbed and/or agglomerated onto the MXene sheets. The electrochemical analysis showed that with the addition of MXene into the nanoparticles, the specific capacitance tested via cyclic voltammetry increased from 225.6 Fg‒1 to 419.5 Fg‒1 at the scan rate of 2 mVs-1, which makes the hybrid a suitable electrode material for supercapacitors. The value of specific capacitance for the hybrid tested via galvanostatic charge‐discharge showed an increased value of 23 Fg‒1 at the current density of 1 Ag-1. The Fourier transform infrared (FTIR) spectroscopy showed that the hybrid contains –O functional groups coming from MXene, which causes an increase in electrochemical activity at the electrode surface, resulting in enhanced capacitance.