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This review presents a comprehensive analysis of the recent formulation of nanoparticle-reinforced solder alloys, focusing on their main properties and improvements in mechanical performance. The introduction provides an overview of solder alloys and the concept of formulating nanoparticle-reinforced solder alloys. The discussion systematically reviews the importance of various properties and critically evaluates the findings from the literature. The review compares and synthesizes the outcomes and insights regarding the impact of nanoparticle addition on the properties and performance of the resulting composite solder alloys. The aim is to identify recent trends, scientific challenges, limitations, and potential breakthroughs in the current formulation of nanoparticle-reinforced solder alloys. The key value of this review lies in the compilation of the latest reports and technical setups, along with the authors' critical analysis and perceptions. This review provides an in-depth understanding and guidance for formulating novel and high-performance nanoparticle-reinforced solder alloys, making it a valuable resource for researchers and engineers in the field of advanced soldering materials.

Thin films are the backbone of the electronics industry, and their widespread application in heat sensors, solar cells, and thin-film transistors has attracted the attention of researchers. The current study involves the deposition of a hetero-structured (ZnO/Zn/ZnO) thin film on a well-cleaned glass substrate using the DC magnetron sputtering technique. The samples were then annealed at 100, 200, 300, 400, and 500 °C. The structural, morphological, and electrical characteristics of the annealed samples as well as one as-deposited sample were then examined using atomic force microscopy (AFM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and a Hall effect measuring apparatus. XRD analysis showed a hexagonal ZnO crystal structure for the samples annealed at 300 and 400 °C, whereas the samples annealed at 100 and 200 °C showed metallic zinc and hexagonal ZnO, and the crystallinity decreased for the sample annealed at 500 °C with pure hexagonal crystal symmetry. According to the AFM study, as the annealing temperature increases, the average roughness (Ra) decreases. Temperature has an inverse relationship with particle size. The optimal annealing temperature was determined to be 400 °C. Over this temperature range, the average roughness and particle size increased. Similarly, when Ra decreased, the conductivity increased and the resistance decreased. A fundamental difficulty is that the heating of the heterostructure to 400 °C melts the Zn-based intermediate layer, which alters the Zn phase and disrupts the sample homogeneity.

This research paper delves into the optoelectronic and thermoelectric properties of the quaternary layered selenide compound CsZrCuSe3, employing a comprehensive computational approach based on density functional theory (DFT) with the HSE06 functional and Boltzmann transport theory. CsZrCuSe3 is a quaternary chalcogenide compound with a tunable bandgap, making it a promising candidate for optoelectronic applications such as photodetectors, solar cells, and LEDs. The electronic properties of CsZrCuSe3 were investigated, revealing a direct bandgap of 1.32 eV at the Γ point. The optical properties, including the dielectric constant and optical conductivity, were analyzed, demonstrating strong absorption in the violet-blue range. Furthermore, the paper explores the thermoelectric properties of CsZrCuSe3, including the Seebeck coefficient, electrical conductivity, thermal conductivity, and the figure of merit (ZT). These properties exhibit intriguing behavior dependent on temperature and chemical potential, with an anomaly observed in the Seebeck coefficient at specific chemical potentials. This anomaly presents an opportunity to gain insights into the complex interplay of electronic properties in semiconductor materials, potentially leading to advancements in thermoelectric applications. Further research and collaboration are essential to decipher the underlying mechanisms and optimize the material for practical use in various technological applications.

A simple approach was used to create Fe3O4-methylcellulose (MC) nanocomposites, which were then analyzed using XRD, FTIR, and FE-SEM to determine their structure. The effective factors for enhancing the ratio of magnetite NPs in the samples were investigated using RTFM and optical absorbance. Fe3O4 was synthesized utilizing the reverse co-precipitation technique and magnetic characteristics. Fe3O4/MC nanocomposites with magnetite/MC weight ratios of 0, 0.07, 0.15, and 0.25 have been developed. The diffraction pattern of magnetite is well indexed in accordance with the spinal reference pattern of Fe3O4 (space group: R¯3m), as confirmed by the Rietveld analysis of XRD data of magnetite NPs with an average crystallite size of 50 nm. Magnetite’s insertion into the MC network causes a red shift in the band gap energy (Eg) as the weight percentage of magnetite nanoparticles in the samples rises. The MC, MC-7, MC-15, and MC-25 samples have Eg values of 5.51, 5.05, 2.84, and 2.20 eV, respectively.

Tin oxide (SnO2) materials were prepared via successive ionic layer adsorption and reaction (SILAR) technique at varying deposition times. The synthesized tin oxide layer served as an electron transport layer for the deposition of a perovskite layer via spin coating method. The morphology, structure, elemental, optical features and vibration modes of the prepared samples have been studied using scanning electron microscopy (SEM), X-ray diffractometry (XRD), energy dispersive X-ray spectroscopy (EDX), UV–vis spectrophotometry, and Raman spectrophotometry, respectively. The films revealed granular-shaped nanograins with a maximum average grain size of 197.03 nm. XRD results showed a cassiterite pure-phase crystal structure with several prominent peaks. EDX studies confirmed the as-deposited elemental constituents with good optical properties obtained from the optical studies. The band gap energies ranged from 4.01 to 4.24 eV at increasing deposition times. The phonon modes and crystal structures were also revealed from the Raman studies. The materials find applications in solar cells and electronic devices.

Currently, the global energy consumption is extensively increasing at a pace faster than the source advancement. The demand for renewable energy generation is an important scheme to settle energy crisis and climate changes which are prominent challenges facing the modern society. Therefore, fabrication of efficient energy storage and conversion technologies have been emerged as a prospective research topic to achieve a convenient utilization of clean energy. In particular, supercapacitors are among the most effective and practically feasible energy storage devices. They offer several characteristic attributes, including fast charging rates, high power densities, extended durability, and convenient setup. Supercapacitor plays an important role as a clean energy device to link conventional capacitors with batteries. This review concentrates on the most recent progress on phosphate-based electroactive materials for supercapacitor application. Phosphate based materials have received curious attention as electrode material for supercapacitors due to their abundance, non-toxicity, and other admirable electrochemical properties. This review presents the recent progress on practical application of phosphate based materials in supercapacitors. The key performance metrics such as power and energy density, capacitance, and cyclic stability of several phosphate based supercapacitor devices have been summarized. Finally, the review present conclusive and future perspectives on the study area.

Bi(2-x)TixO3 (x = 0, 0.01, 0.03. & 0.05) (BO-xT) ceramics are prepared by conventional solid-state route followed by low sintering temperatures. X-ray diffraction analyses show the presence of the monoclinic phase of Bi2O3. The electrical conductivities at room temperature concerning the frequency (ranging from 25 kHz to 5 MHz) and Seebeck Coefficient ranging from 50°C to 400°C were measured. With an increase in Ti (dopant) content, the conductivity and Seebeck Coefficient increased with the temperature increment. The BO-0.03T has the highest Seebeck value (47 μV/°C), which shows a higher carrier concentration. In terms of electrical conductivities, the BO-0.05T ceramic shows the maximum electrical conductivity, i.e. 2.0 × 10−9 μS/m as compared to other samples, which exhibit the presence of free electrons. Moreover, relative permittivity (dielectric constant) and dielectric loss are also measured concerning the frequency at room temperature to investigate the dielectric behaviour of the ceramics. This low-temperature sintering ceramics will open new applications in the domain of electronic materials.

Although, zinc oxide nanoparticles (ZRTs) as an anti-cancer agent have been the subject of numerous studies, none of the reports has investigated the impact of the reaction entry time of ion-carriers on the preparation of ZRTs. Therefore, we synthesized variants of ZRTs by extending the entry time of NaOH (that acts as a carrier of hydroxyl ions) in the reaction mixture. The anti-proliferative action, morphological changes, reactive oxygen species (ROS) production, and nuclear apoptosis of ZRTs on human A431 skin carcinoma cells were observed. The samples revealed crystallinity and purity by X-ray diffraction (XRD). Scanning electron microscopy (SEM) images of ZRT-1 (5 min ion carrier entry) and ZRT-2 (10 min ion carrier entry) revealed microtubule like morphology. On prolonging the entry time for ion carrier (NaOH) introduction in the reaction mixture, a relative ascent in the aspect ratio was seen. The typical ZnO band with a slight shift in the absorption maxima was evident with UV-visible spectroscopy. Both ZRT-1 and ZRT-2 exhibited non-toxic behavior as evident by RBC lysis assay. Additionally, ZRT-2 showed better anti-cancer potential against A431 cells as seen by MTT assay, ROS generation and chromatin condensation analyses. At 25 μM of ZRT-2, 5.56% cells were viable in MTT test, ROS production was enhanced to 166.71%, while 33.0% of apoptotic cells were observed. The IC50 for ZRT-2 was slightly lower (6 μM) than that for ZRT-1 (8 μM) against A431 cells. In conclusion, this paper presents a modest, economical procedure to generate ZRT nano-structures exhibiting strong cytotoxicity against the A431 cell line, indicating that ZRTs may have application in combating cancer.

In this study, we synthesized cobalt sulfide (CoS) nanostructures for supercapacitor applications via a one-step hydrothermal method. The effect of hydrothermal temperature on the synthesis process was investigated at temperatures ranging from 160 °C to 220 °C. The structural, morphological, and elemental analyses were performed using X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), and scanning electron microscopy (SEM). The XRD patterns show the hexagonal phase of CoS, and the samples prepared at 200 °C have high crystallinity. The samples prepared at other temperatures show amorphousness at lower 2-theta angles. EDX indicated that the sample was of high purity, except that the sample prepared at 220 °C had an additional oxygen peak, indicating that sulfur is not stable at high temperatures. In addition, a cobalt oxide (CoO) peak is also observed in the XRD data of the sample prepared at 220 °C. SEM images show that the particles in the samples prepared at 160 °C and 180 °C are agglomerated due to the high surface energy, whereas the samples prepared at 200 °C and 220 °C have a distinct morphology. Electrochemical analyses such as cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic charge–discharge (GCD) were performed on all samples. The CoS sample prepared at 200 °C exhibited a high specific capacitance (Csp) of 1583 F/g at a current density of 1 A/g, with low resistivity and high cycling stability.

In the present research, groups of nanolayered structures and nanohybrids based on organic green dyes and inorganic species are designated to act as fillers for PVA to induce new optical sites and increase its thermal stability through producing polymeric nanocomposites. In this trend, different percentages of naphthol green B were intercalated as pillars inside the Zn-Al nanolayered structures to form green organic-inorganic nanohybrids. The two-dimensional green nanohybrids were identified by X-ray diffraction, TEM and SEM. According to the thermal analyses, the nanohybrid, which has the highest amount of green dyes, was used for modifying the PVA through two series. In the first series, three nanocomposites were prepared depending on the green nanohybrid as prepared. In the second series, the yellow nanohybrid, which was produced from the green nanohybrid by thermal treatment, was used to produce another three nanocomposites. The optical properties revealed that the polymeric nanocomposites depending on green nanohybrids became optical-active in UV and visible regions because the energy band gap decreased to 2.2 eV. In addition, the energy band gap of the nanocomposites which depended on yellow nanohybrids was 2.5 eV. The thermal analyses indicated that the polymeric nanocomposites are thermally more stable than that of the original PVA. Finally, the dual functionality of organic-inorganic nanohybrids that were produced from the confinement of organic dyes and the thermal stability of inorganic species converted the non-optical PVA to optical-active polymer in a wide range with high thermal stability.

In this work, a simple sensitive validated liquid chromatography mass spectroscopy (LC-MS/MS) analytical method was developed for the determination of Spirodiclofen residues in different aquatic toxic media. The toxic media were those that provide nutrients and help with the growth of different aquatic organisms for their survival and multiplication. The different media were the M4 medium for Daphnia magna and The Organization for Economic Cooperation and Development (OECD TG 201) medium for alga. Fe2O3-Ag2O/TiO2 nanocomposites were prepared by using a precipitation method, which was used as a photo-catalyst for the removal of Spirodiclofen pesticide from aquatic media. The experiment was performed under direct sunlight at a single fortification level (1.0 µg/mL) in M4 and OECD TG 201 media. The optimum catalyst concentration for the complete degradation was found to be 10 mg/L under sunlight. Spirodiclofen residues in water were determined by LC-MS/MS, and the rate constant DT50 (half-life) values were calculated from the obtained data. The results showed that with Fe2O3-Ag2O/TiO2 nanocatalyst, the DT50 (half-life) value was found to be approximately 8 h. These results revealed that iron-oxide- and silver-oxide-incorporated TiO2 nanocomposites were excellent photocatalysts when compared with TiO2, Fe2O3-TiO2, and Ag2O-TiO2 for the decontamination of pesticide residues in aquatic media samples.

The precipitation process was applied to synthesize chitosan-coated zinc oxide nanoparticles (chitosan-ZnO NPs). Then, various characterization tools were used such as XDR, SEM, TEM, FTIR, and EDX. The use of these 50 nm chitosan-ZnO NPs in soil decontamination of thifluzamide and difenoconazole pesticide residues is being investigated. In two distinct soils, the effect of catalytic decontamination on pesticide residues was examined (sandy loam and sandy clay soils). The studies required two sets of pesticide concentrations. One set of samples was added to the chitosan-ZnO NPs catalyst, and the other set was studied without the addition of a catalyst. Photocatalytic studies were conducted under the sunlight in July. The soil samples were hand-spread in a glass dish to a height of 5 mm and sprayed with an aqueous solution of pesticide. From 8 a.m. to 5 p.m., these samples were exposed to sunlight in October 2021. We found that the best concentration of catalyst was 0.05%. The acquired samples were quantified using validated Ultra-Fast Liquid Chromatography (UFLC) with Photo Diode Array (PDA) detection. Kinetic parameters such as rate constant k and the degradation rate of pesticides DT50 have been calculated using Pesticide Residue Dissipation Data. The findings showed that the tested fungicides degenerate according to pseudo-first-order kinetics. Based on the findings, we concluded that photocatalytic degradation of pesticides in soils are faster than photolysis.

Moringa oleifera is rich in bioactive compounds such as beta-carotene, which have high nutritional values and antimicrobial applications. Several studies have confirmed that bioactive-compound-based herbal medicines extracted from the leaves, seeds, fruits and shoots of M. oleifera are vital to cure many diseases and infections, and for the healing of wounds. The β-carotene is a naturally occurring bioactive compound encoded by zeta-carotene desaturase (ZDS) and phytoene synthase (PSY) genes. In the current study, computational analyses were performed to identify and characterize ZDS and PSY genes retrieved from Arabidopsis thaliana (as reference) and these were compared with the corresponding genes in M. oleifera, Brassica napus, Brassica rapa, Brassica oleracea and Bixa orellana. The BLAST results revealed that all the plant species considered in this study encode β-carotene genes with 80–100% similarity. The Pfam analysis on β-carotene genes of all the investigated plants confirmed that they belong to the same protein family and domain. Similarly, phylogenetic analysis revealed that β-carotene genes of M. oleifera belong to the same ancestral class. Using the ZDS and PSY genes of Arabidopsis thaliana as a reference, we conducted qRT-PCR analysis on RNA extracted from the leaves of M. oleifera, Brassica napus, Brassica rapa and Bixa orellana. It was noted that the most significant gene expression occurred in the leaves of the studied medicinal plants. We concluded that not only are the leaves of M. oleifera an effective source of bioactive compounds including beta carotene, but also the leaves of Brassica napus, Brassica rapa and Bixa orellana can be employed as antibiotics and antioxidants against bacterial or microbial infections.

Micro- and meso-porous structures of alumina have attracted attention for their potential use in different applications. In this research, a novel and facile route was introduced for dual growth of alumina nanoparticles and carbon nanotubes together to fabricate nanocomposites at low temperature 250 °C through explosive processes of solid fuel. In this trend, series of alumina species with and without carbon nanotubes were prepared and characterized by X-ray diffraction, Raman spectra and transmission electron microscopy.The surface properties of the alumina-CNT nanocomposites were characterized and compared with the prepared nanoparticles of alumina by adsorption–desorption system. The specific surface area of the prepared alumina-CNT nanocomposites was increased from 257.9 to 307.7 m2/g and 314.8 m2/g with growing CNTs inside the porous structure of alumina. These increments were observed because of the dual growth of nanoparticles and nanotubes by which new micropores inside their nanocomposites were created. When the source of CNTs was changed from ethanol to methanol, pure mesoporous structure with narrow pore size distribution was observed for the alumina-CNT nanocomposite. In addition, the surface area and the total pore volume increased to be 324.9 m2/g and 0.673 cm3/g; respectively.The detonation technique of an explosive solid has been used for the first time to improve and control the porous structure of alumina through dual growth of CNTs and alumina at low temperature to meet the special requirements of the markets of catalysis and water purification. Keywords: Microporous structure, Mesoporous structure, Alumina texture control, CNT-alumina dual growth at low temperature, Detonation of explosive solids

Sr _1-x Gd _x TiO _3 (0.00 ≤ x ≤ 0.11) ceramics by the addition of Gd ^3+ on A-sites, were processed and fabricated through the conventional sintering method and optimised the sintering temperature at 1390 °C–1470 °C for 2 h. The experimentation shows that all ceramics are possessed by cubic structure, in which the increment of Gd ^3+ content, in terms of x, decreases the lattice parameters of the ceramics, as well as affects the grain size. Comparing the results to pure SrTiO _3 (STO) compounds, the addition of Gd ^3+ lowers the mass loss, increased the conductivity as well as permittivity by decreasing the dielectric losses at lower frequencies. The x = 0.03 and 0.01 evidenced the maximum Seeback Coefficient, ∼281 μ V K ^−1 at ∼370 K confirming the higher carrier concentration. Also, the magnetic properties as a function of Gd ^3+ ions doped with STO showed gradual improvement, showing maximum saturation with the maximum concentration of x.

Porous carbons are highly attractive and demanding materials which could be prepared using biomass waste; thus, they are promising for enhanced electrochemical capacitive performance in capacitors and cycling efficiency in Li-ion batteries. Herein, biomass (rice husk)-derived activated carbon was synthesized via a facile chemical route and used as anode materials for Li-ion batteries. Various characterization techniques were used to study the structural and morphological properties of the prepared activated carbon. The prepared activated carbon possessed a carbon structure with a certain degree of amorphousness. The morphology of the activated carbon was of spherical shape with a particle size of ~40–90 nm. Raman studies revealed the characteristic peaks of carbon present in the prepared activated carbon. The electrochemical studies evaluated for the fabricated coin cell with the activated carbon anode showed that the cell delivered a discharge capacity of ~321 mAhg−1 at a current density of 100 mAg−1 for the first cycle, and maintained a capacity of ~253 mAhg−1 for 400 cycles. The capacity retention was found to be higher (~81%) with 92.3% coulombic efficiency even after 400 cycles, which showed excellent cyclic reversibility and stability compared to commercial activated carbon. These results allow the waste biomass-derived anode to overcome the problem of cyclic stability and capacity performance. This study provides an insight for the fabrication of anodes from the rice husk which can be redirected into creating valuable renewable energy storage devices in the future, and the product could be a socially and ethically acceptable product.

The doping of magnesium on lithium aluminium borate phosphor is reported in this study. A solid-state sintering technique was employed as the borate samples were synthesized. This report focuses on the structural, optical, thermoluminescence, and kinetic analyses of the main glow peak. The structural properties of lithium aluminium borates improved due to the magnesium dopants used. Differences in the crystallite size and particle size were 38.85–67.35 nm and 50–60 nm, respectively, and these results were obtained from the analyzed X-ray diffractogram and scanning electron spectroscopy. The energy band gaps obtained from the direct transition of borate phosphor materials were within the range of 3.00–4.40 eV, and the doped samples gave a higher energy band gap. A decrease in the TGA (%) exhibited a weight loss or water loss for the undoped, 0.1% Mg, and 0.3% Mg-doped lithium aluminium borate materials. The glow curve measured at a heat rate of 1 °C·s−1 after irradiation to 50 Gy revealed four peaks related to the magnesium doped lithium aluminium borate. The main glow peak was observed at 86 °C. Activation energy was extracted from the main glow peak by using kinetic analysis which involves the initial rise, deconvolution, and variable heating rate approach, and it was approximately 0.67 ± 0.03 eV. A shift in the main glow peak curve from 86 to 110 °C was recognized for the magnesium-doped lithium aluminium borate when it was irradiated from 1 to 300 Gy.

ZnO nanostructures were grown on a Si(111) substrate using a vapor–liquid–solid (VLS) growth procedure (pristine ZnO) and annealed via a rapid thermal-annealing process in an argon atmosphere at 1100 °C (Ar-ZnO). The synthesized ZnO nanostructures were investigated through structural, electronic structural, morphological, optical, and magnetic characterizations. X-ray diffraction and selective area electron diffraction (SAED) measurements revealed that both samples exhibited the hexagonal wurtzite phase of nanocrystalline ZnO. Near-edge X-ray absorption fine structure (NEXAFS) spectroscopy carried out at the O K-edge inferred the presence of the intrinsic-defect states. Field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy images displayed the formation of ZnO nanostructures. The photoluminescence (PL) spectra demonstrated an emission band in the UV region along with an additional defect band in the visible region. PL spectral analysis confirmed the presence of intrinsic defects in Ar-ZnO nanowires, contributing to the enhanced emission in the visible region. The Raman spectra showed the characteristic band (434 cm−1) corresponding to the vibrational modes of hexagonal wurtzite ZnO, with an additional band attributable to intrinsic defects. DC magnetization measurements showed a ferromagnetic response in both samples with enhanced coercivity in Ar-ZnO (~280 Oe). In brief, both samples exhibited the presence of intrinsic defects, which are found to be further enhanced in the case of Ar-ZnO. Therefore, it is suggested that intrinsic defects have played an important role in modifying the optical and magnetic properties of ZnO with enhanced results for Ar-ZnO.

In this paper, the sol-gel technique has been employed to prepare the pure and TM (Mn, Cr) doped BiFeO3 nanoparticles. The synthesized nanoparticles were characterized using X-ray diffraction, UV-vis spectroscopy, photoluminescence, and dielectric measurements. Crystal structural analysis infers that pure and TM-doped BiFeO3 nanoparticles displayed a rhombohedral distorted perovskite structure with R3c space group, along with a minor phase of Bi2Fe4O9. Lattice parameters have been found to decrease with TM doping. The particle size, measured with the help of the XRD spectra, was found to decrease from 54.4 nm to 38.7 nm with TM doping. The bandgap, determined using the UV-vis spectra, was observed to be 1.92, 1.66, and 1.54 eV for undoped, 5% Mn, and 5% Cr-doped BiFeO3 nanoparticles, respectively. The dielectric constant shows a normal dispersion behavior at room temperature and its value increases with TM doping. The ac conductivity also increases with TM doping in BiFeO3 nanoparticles.

In this work, the chemical bath deposition (CBD) technique was utilized in the synthesis of transition metals/GO nanocomposites (Co3O4/MnO2/NiO/GO) for applications in supercapacitor electrodes. The nanocomposites after characterization showed that the electrically conductive nature and wide surface area of graphene oxide (GO) accounted for its incorporation into the nanocomposites. The synergy between the nanocomposites accounts for their improved performance and stable phase. The XRD results revealed cubic, orthorhombic, cubic, and mixed phases for the Co3O4/GO (CG), MnO2/GO (MG), NiO/GO (NG), and Co3O4/MnO2/NiO/GO (CMNG), respectively; their morphologies showed platelet nanoparticles with few agglomerates, with an average particle size of 69 ± 12 nm, 37 ± 09 nm, 58 ± 36 nm, and 36 ± 08 nm, respectively. For the produced materials, electrochemical results revealed maximum specific capacitance values of 2482 F/g from cyclic voltammograms and 1280.48 F/g from the galvanometric test. The results showed that the composites outperform single transition metal oxide (TMO) electrodes, with graphene oxide boosting the electrode performance.

In the present work, Cu-doped ZnO nanostructures (Cu% = 0, 1, 5) have been prepared using microwave-assisted chemical route synthesis. The synthesized nanostructures were investigated through structural, morphological, optical, and magnetic characterizations. The results of the X-ray diffraction (XRD), high resolution transmission electron microscopy (HR-TEM), and selective area electron diffraction (SAED) patterns confirmed that all of the samples exhibit the single-phase polycrystalline hexagonal crystal structure. The XRD results infer a decrease in the lattice parameters (a/c) by increasing the Cu% doping into ZnO. The field emission scanning electron microscopy (FE-SEM) and energy dispersive x-ray (EDX) spectroscopic measurements revealed the formation of nanostructures, showing the major elemental presence of Zn and O in the samples. The photoluminescence (PL) spectra exhibited photoemission in the UV and blue-green regions. With the increase in the Cu%, the photoemission in the UV region is reduced, while it is enhanced in the blue-green region. Raman spectra of the Cu-doped ZnO nanostructures displayed a blue shift of the E2High mode and an increase in the peak intensity of E1(LO), indicating the doping of Cu ion in the ZnO lattice. The dc magnetization measurements demonstrated the ferromagnetic behavior of all of the samples with an enhanced ferromagnetic character with increasing Cu%.

Magnetic nanostructures of CoFe2O4 were synthesized via a microwave-assisted hydrothermal route. The prepared nanostructures were investigated using X-ray diffraction (XRD), field emission electron microscopy (FE-SEM), energy dispersive X-ray (EDX) spectroscopy, high-resolution transmission electron microscopy (HR-TEM), selective area electron diffraction (SAED) pattern, DC magnetization, and dielectric spectroscopy measurements. The crystal structure studied using HR-TEM, SAED, and XRD patterns revealed that the synthesized nanostructures had a single-phase nature and ruled out the possibility of any secondary phase. The lattice parameters and unit cell volume determined from the XRD data were found to be 8.4821 Å and 583.88 Å3. The average crystallite size (~7.0 nm) was determined using Scherrer’s equation. The FE-SEM and TEM micrographs revealed that the prepared nanostructures had a spherical shape morphology. The EDX results showed that the major elements present in the samples were Co, Fe, and O. The magnetization (M) versus temperature (T) measurements specified that the CoFe2O4 nanostructures showed ferromagnetic ordering at room temperature. The blocking temperature (TB) determined using the M-T curve was found to be 315 K. The magnetic hysteresis (M-H) loop of the CoFe2O4 nanostructures recorded at different temperatures showed the ferromagnetic behavior of the CoFe2O4 nanostructures at temperatures of 200 K and 300 K, and a superparamagnetic behavior at 350 K. The dielectric spectroscopy studies revealed a dielectric constant (ε′) and loss tangent (tanδ) decrease with the increase in the frequency, as well as demonstrating a normal dispersion behavior, which is due to the Maxwell–Wagner type of interfacial polarization. The values of ε′ and tanδ were observed to increase with the increase in the temperature.

Herein, we present an electrocatalyst constructed by zinc oxide hexagonal prisms/phosphorus-doped carbon nitride wrinkles (ZnO HPs/P-CN) prepared via a facile sonochemical method towards the detection of nitrofurantoin (NF). The ZnO HPs/P-CN-sensing platform showed amplified response and low-peak potential compared with other electrodes. The exceptional electrochemical performance could be credited to ideal architecture, rapid electron/charge transfer, good conductivity, and abundant active sites in the ZnO HPs/P-CN composite. Resulting from these merits, the ZnO HPs/P-CN-modified electrode delivered rapid response (2 s), a low detection limit (2 nM), good linear range (0.01–111 µM), high sensitivity (4.62 µA µM−1 cm2), better selectivity, decent stability (±97.6%), and reproducibility towards electrochemical detection of NF. We further demonstrated the feasibility of the proposed ZnO HPs/P-CN sensor for detecting NF in samples of water and human urine. All the above features make our proposed ZnO HPs/P-CN sensor a most promising probe for detecting NF in natural samples.

We report a theoretical investigation of the influence of Cu doping into TiO2 with various concentrations on crystal structure, stability, electronic structures and optical absorption coefficient using density functional theory via the hybrid formalism based on Heyd Scuseria Ernzerhof. Our findings show that oxygen-rich environments are better for fabricating Cu-doped materials and that the energy of formation for Cu doping at the Ti site is lower than for Cu doping at the O site under these environments. It is found that Cu doping introduces intermediate bands into TiO2, narrowing the band gap. Optical absorption curves show that the Cu-doped TiO2 can successfully harvest visible light. The presence of widely intermediate bands above the valence-band edge could explain the increase in the visible light absorption range. However, the intensity of visible light absorption rises with the increase in doping concentration.

In this paper, the photocatalytic effect of zirconia/laser-induced graphene on the degradation of methylene blue was comprehensively studied. The average particle size measured by HRTEM is 6 nm for both ZrO2 and ZrO2/G10 samples, which explains the high-quality TEM imaging of isolated squared sections of cubic particles. The weight percentages of Zr, O, and C elements using EDX were 72.16, 18.56, and 9.28, respectively. These results confirm the formation of binary composites. Moreover, Raman scattering exhibited that the spectrum of pure ZrO2 was difficult to be detected due to the high luminescence. However, ZrO2 vibration modes were detected for ZrO2-graphene nanocomposites at 1012, 615, 246, and 150 cm−1. A shift of the D- and G-bands of graphene were observed, where D-peak and G-peak were observed at 1370 and 1575 cm−1 for ZrO2/5G and, 1361 and 1565 cm−1 for ZrO2/10G, respectively. The shift is ascribed to the incorporation of graphene into the surface of the oxide material. Compared to ZrO2, the newly fabricated ZrO2-graphene nanocomposites have the advantage of increased photocatalytic effects. An adsorbent concentration of 5 and 10 mg·L−1 at room temperature over 240 min was observed to be suitable experimental conditions. The kinetic results indicate that the practical results obtained are well expressed by the first-order kinetic model at different concentrations. In addition, the results showed that the addition of graphene led to a significant degradation process increase. The results also showed the significant effect of the investigated ZrO2-graphene nanocomposites on the decomposition of methylene blue cation. The decomposition of cationic pollutants showed a synergistic effect of the ZrO2-graphene nanocomposites on wastewater treatment.

(Nb5+, Si4+) co-doped TiO2 (NSTO) ceramics with the compositions (Nb0.5Si0.5)xTi1−xO2, x = 0, 0.025, 0.050 and 0.1 were prepared with a solid-state reaction technique. X-ray diffraction (XRD) patterns and Raman spectra confirmed that the tetragonal rutile is the main phase in all the ceramics. Additionally, XRD revealed the presence of a secondary phase of SiO2 in the co-doped ceramics. Impedance spectroscopy analysis showed two contributions, which correspond to the responses of grain and grain-boundary. All the (Nb, Si) co-doped TiO2 showed improved dielectric performance in the high frequency range (>103 Hz). The sample (Nb0.5Si0.5)0.025Ti0.975O2 showed the best dielectric performance in terms of higher relative permittivity (5.5 × 104) and lower dielectric loss (0.18), at 10 kHz and 300 K, compared to pure TiO2 (1.1 × 103, 0.34). The colossal permittivity of NSTO ceramics is attributed to an internal barrier layer capacitance (IBLC) effect, formed by insulating grain-boundaries and semiconductor grains in the ceramics.

The nanoparticles of CeO2, Ce0.98Fe0.02O2, and Ce0.78Fe0.02Cu0.20O2 were synthesized using the co-precipitation-synthesis technique. The effect of co-doping of Fe and Cu on structural, optical, and magnetic properties as well as specific capacitance have been studied using X-ray diffraction (XRD), scanning-electron microscopy (SEM), UV-visible spectroscopy, Raman spectroscopy, dc magnetization, and electrochemical measurements at room temperature. The results of the XRD analysis infer that all the samples have a single-phase nature and exclude the formation of any extra phase. Particle size has been found to reduce as a result of doping and co-doping. The smallest particle size was obtained to be 5.59 nm for Ce0.78Fe0.02Cu0.20O2. The particles show a spherical-shape morphology. Raman active modes, corresponding to CeO2, were observed in the Raman spectra, with noticeable shifting with doping and co-doping indicating the presence of defect states. The bandgap, calculated using UV-Vis spectroscopy, showed relatively low bandgap energy (1.7 eV). The dc magnetization results indicate the enhancement of the magnetic moment in the samples, with doping and co-doping. The highest value of saturation magnetization (1.3 × 10−2 emu/g) has been found for Ce0.78Fe0.02Cu0.20O2 nanoparticles. The electrochemical behavior studied using cyclic-voltammetry (CV) measurements showed that the Ce0.98Fe0.02O2 electrode exhibits superior-specific capacitance (~532 F g−1) along with capacitance retention of ~94% for 1000 cycles.

Water pollution and deficient energy are the main challenges for the scientific society across the world. In this trend, new approaches include designing zinc oxide nanohybrids to be very active in sunlight. In this line, organic and magnetic species intercalate among the nanolayers of Al/Zn to build inorganic-magnetic-organic nanohybrid structures. A series of nanolayered and nanohybrid structures have been prepared through intercalating very fine particles of cobalt iron oxide nanocomposites and long chains of organic fatty acids such as n-capric acid and stearic acid inside the nanolayered structures of Al/Zn. By thermal treatment, zinc oxide nanohybrids have been prepared and used for purifying water from colored pollutants using solar energy. The optical measurements have shown that the nanohybrid structure of zinc oxide leads to a clear reduction of band gap energy from 3.30 eV to 2.60 eV to be effective in sunlight. In this line, a complete removal of the colored pollutants (naphthol green B) was achieved after ten minutes in the presence of zinc oxide nanohybrid and sunlight. Finally, this new approach for designing photoactive nanohybrids leads to positive results for facing the energy- and water-related problems through using renewable and non-polluting energy for purifying water.

Energy and water related problems have attracted strong attention from scientists across the world because of deficient energy and water pollution. Following this line, new strategy depended on preparing nanolayers of Al/Zn and magnetic nanoparticles of cobalt iron oxides nanocomposite in addition to long chains of hydrocarbons of stearic acid to be used as roofs, fillers and pillars; respectively, to design optical-active nanohybrids in sunlight for removing the colored pollutants from water in few minutes. By using long chains of hydrocarbons of stearic acid, X-ray diffraction (XRD) results and TEM images showed expansion of the interlayered spacing from 0.76 nm to 2.02 nm and insertion of magnetic nanoparticles among the nanolayers of Al/Zn. The optical properties and activities showed that the nanohybrid structure based on zinc oxide led to clear reduction of the band gap energy from 3.3 eV to 2.75 eV to be effective in sunlight. Photocatalytic degradation of the dye of acid green 1 confirmed the high activity of the prepared zinc oxide nanohybrids because of a complete removal of the dye after ten minutes in sunlight. Finally, this strategy was effective for producing photo-active nanohybrids for using renewable and non-polluting energy for purifying water.

BiFe1−xCrxO3, (0 ≤ x ≤ 10) nanoparticles were prepared through the sol–gel technique. The synthesized nanoparticles were characterized using various techniques, viz., X-ray diffraction, high-resolution field emission scanning electron microscopy (HRFESEM), energy dispersive spectroscopy (EDS), UV–Vis absorption spectroscopy, photoluminescence (PL), dc magnetization, near-edge X-ray absorption spectroscopy (NEXAFS) and cyclic voltammetry (CV) measurements, to investigate the structural, morphological, optical, magnetic and electrochemical properties. The structural analysis showed the formation of BiFeO3 with rhombohedral (R3c) as the primary phase and Bi25FeO39 as the secondary phase. The secondary phase percentage was found to reduce with increasing Cr content, along with reductions in crystallite sizes, lattice parameters and enhancement in strain. Nearly spherical shape morphology was observed via HRFESEM with Bi, Fe, Cr and O as the major contributing elements. The bandgap reduced from 1.91 to 1.74 eV with the increase in Cr concentration, and PL spectra revealed emissions in violet, blue and green regions. The investigation of magnetic field (H)-dependent magnetization (M) indicated a significant effect of Cr substitution on the magnetic properties of the nanoparticles. The ferromagnetic character of the samples was found to increase with the increase in the Cr concentration and the increase in the saturation magnetization. The Fe (+3/+4) was dissolved in mixed-valence states, as found through NEXAFS analysis. Electrochemical studies showed that 5%-Cr-doped BFO electrode demonstrated outstanding performance for supercapacitors through a specific capacitance of 421 F g−1 measured with a scan rate of 10 mV s−1. It also demonstrated remarkable cyclic stability through capacitance retention of >78% for 2000 cycles.

Nanocomposite (NC) films of polyvinyl alcohol (PVA), lignosulfonate (Lg), and nanosized palladium (Pd) were synthesized by ex-situ casting method. Samples from the synthesized PVA-Lg/Pd NC films were irradiated with 5–100 kGy γ doses. The effect of γ doses on the structural, thermal, and optical characteristics of the NC films were studied using different characterization techniques. The results indicated that the γ irradiation improves the decomposition temperature from 227 to 239 °C, signifying an increase in the thermal stability of the NC films. This was accompanied by a reduction of the melting temperature due to the increase of the amorphous phase. This can be attributed to the dominance of crosslinking. On the other hand, the refractive index increased from 2.21 to 2.32 while increasing the γ dose up to 100 kGy. This was associated with a reduction of the optical bandgap from 3.49 to 3.30 eV, which could be attributed to the increase in the amorphous phase as a result of crosslinking. This indicates an enhancement of the spreading of the NPs inside the blend matrix due to γ irradiation. This results in a more compacted construction of the PVA-Lg/Pd NC films. Furthermore, we used the Commission Internationale de E’Claire (CIE) method to estimate the change in color among the irradiated NC films and the pristine film. The PVA-Lg/Pd NC attained a significant color difference value greater than five, meaning permanent color changes.

Advanced photo-active materials have attracted attention for their potential uses in water purification. In this study, a novel and facile route was used for designing nanohybrids to be valuable sources for producing effective photocatalysts for purifying water from the colored pollutants. Host-guest interaction and intercalation reactions used long chains of hydrocarbons of n-capric acid and stearic acid to facilitate incorporation of fine particles of cobalt iron oxide nanocomposite with the internal surface of the nanolayers of Al/Zn for building nanohybrids. The thermal decomposition of the prepared nanohybrids led to formation of zinc oxide nanoparticles doped with multi-oxides of magnetic and non-magnetic dopants. These dopants created new optical centers causing a strong reduction in the band gap energy from 3.30 eV to 2.60 eV. This positive effect was confirmed by a complete removal of the dye of Naphthol green B from water after 15 min of light irradiation. Moreover, a kinetic study showed that the reaction rate of photocatalytic degradation of the pollutants was faster than that of the conventional photocatalysts. Finally, this route was effective for producing benign and fast solutions for purifying water in addition to environment-related problems.

Hydrothermally synthesized electrodes of Co3O4@MnO2@NiO/GO were produced for use in supercapacitors. Graphene oxide (GO) was incorporated into the nanocomposites used for electrode synthesis due to its great surface area and electrical conductivity. The synergistic alliance among these composites and GO enhances electrode performance, life span, and stability. The structural properties obtained from the X-ray diffraction (XRD) results suggest that nanocomposites are crystalline in nature. The synergistic alliance among these composites and GO enhances electrode performance, life span, and stability. Performance assessment of these electrodes indicates that their characteristic performance was enhanced by C2+ radiation, with the uttermost performance witnessed for electrodes radiated with 5.0 × 1015 ions/cm2.

In the current study, Bi2/3Cu3Ti4O12 (BCTO) ceramics were prepared by mechanical ball mill of the elemental oxides followed by conventional sintering of the powder without any pre-sintering heat treatments. The sintering temperature was in the range 950–990 °C, which is 100–150 °C lower than the previous conventional sintering studies on BCTO ceramics. All the ceramic samples showed body-centered cubic phase and grain size ≈ 2–6 μm. Sintering temperature in the range 950–975 °C resulted in comparatively lower dielectric loss and lower thermal coefficient of permittivity in the temperature range from −50 to 120 °C. All the BCTO ceramics showed reasonably high relative permittivity. The behavior of BCTO ceramics was correlated with the change in oxygen content in the samples with sintering temperature. This interpretation was supported by the measurements of the energy dispersive x-ray spectroscopy (EDS) elemental analysis and activation energy for conduction and for relaxation in the ceramics.

We investigated the effects of applying an external electric field on the electronic properties of Stone-Wales (SW) defective carbon-boron-nitride nanotubes (CBN) using first principles calculations. The defective CBN nanotubes were modeled by introducing Stone–Wales defects in the boron-nitride segment (BN-SW), the carbon segment (C-SW), and the carbon-boron-nitride interface segment (CBN-SW). Initially, we studied the formation energies and the structural stability for all models. As a result of adding the SW defects, the calculated bandgap values of the C-SW and CBN-SW models showed significant changes compared to the pristine CBN nanotube. Meanwhile, the BN-SW model showed a slight bandgap change because of the strong covalent bonding between the boron and nitrogen atoms. Applying a transverse electric field induced a fast bandgap closing response in all models, indicating a rapid semiconductor-to-metal phase transition. The defective C-SW and CBN-SW models demonstrated unique bandgap closing patterns in response to applied transverse and longitudinal electric fields, while pristine and BN-SW models had similar bandgap responses.

Oxide perovskites doped with rare-earth have shown change in optoelectronic properties with high dielectric constants. Herein, the structural, electronic, and optical characteristics of BaTiO3 doped with ytterbium at the Ba and Ti sites were studied by employing the first-principles density functional calculations. The Tran-Blaha modified Becke-Johnson (TB-mBJ) potential and GGA + U approaches have been used for determining the optoelectronic properties. We probed the impact of the ytterbium incorporation at the Ti and Ba sites into BaTiO3 by tuning of the structural geometry and electronic structure behavior and dielectric constants. A detailed analysis, of structural properties, reveals that lattice parameters of ytterbium doping shift slightly regarding those of pristine BaTiO3. The BaO and TiO bond lengths were reduced due to the crystalline structure lattice distortion. The band structures demonstrate that ytterbium doping has induced various changes in the electronic nature of BaTiO3 by creating a magnetism. For both Ba and Ti sites, ytterbium doping has strongly increased the BaTiO3 dielectric constants.

In the current study, we report on the dielectric behavior of colossal-dielectric-constant Na1/2La1/2Cu3Ti4O12 (NLCTO) ceramics prepared by mechanochemical synthesis and spark plasma sintering (SPS) at 850 °C, 900 °C, and 925 °C for 10 min. X-ray powder diffraction analysis showed that all the ceramics have a cubic phase. Scanning electron microscope observations revealed an increase in the average grain size from 175 to 300 nm with an increase in the sintering temperature. SPS NLCTO ceramics showed a room-temperature colossal dielectric constant (>103) and a comparatively high dielectric loss (>0.1) over most of the studied frequency range (1 Hz–40 MHz). Two relaxation peaks were observed in the spectra of the electrical modulus and attributed to the response of grain and grain boundary. According to the Nyquist plots of complex impedance, the SPS NLCTO ceramics have semiconductor grains surrounded by electrically resistive grain boundaries. The colossal dielectric constant of SPS NLCTO ceramics was attributed to the internal barrier layer capacitance (IBLC) effect. The high dielectric loss is thought to be due to the low resistivity of the grain boundary of SPS NLCTO.

In the present work we have studied the transport and dielectric behavior of BaTi0.7Zr0.3O3 (BTZ30) relaxor ferroelectrics prepared by spark plasma sintering. Nanocrystalline powder of BTZ30 was obtained by solid state reaction followed by mechanical milling. Fine and coarse-grained ceramics of BTZ30 were prepared by spark plasma sintering at 1100 and 1400 °C, respectively. The obtained materials were characterized by X-ray diffraction and scanning electron microscopy. The grain size of the BTZ30 ceramics increased from 200 nm to 3–5 μm as the sintering temperature was increased from 1100 °C to 1400 °C. The electrical and dielectric properties of BTZ30 ceramics were studied by impedance spectroscopy over −150 to +200 °C temperature range. The dielectric constant exhibits very large values >105 for the spark plasma sintered ceramics associated with very high dielectric loss and electrical conductivity. The insulating nature of the BTZ30 ceramics could be retained by re-oxidation of the samples. The dielectric data of the annealed have been analyzed by the modified Curie-Weiss law and the relaxation process in the materials was fitted by Vogel-Fulcher model. Keywords: Barium titanate zirconate, Relaxor ferroelectrics, Spark plasma sintering, Dielectric properties

In this study, high specific surface areas (SSAs) of anatase titanium dioxide (TiO2) quantum dots (QDs) were successfully synthesized through a novel one-step microwave–hydrothermal method in rapid synthesis time (20 min) without further heat treatment. XRD analysis and HR-TEM images showed that the as-prepared TiO2 QDs of approximately 2 nm size have high crystallinity with anatase phase. Optical properties showed that the energy band gap (Eg) of as-prepared TiO2 QDs was 3.60 eV, which is higher than the standard TiO2 band gap, which might be due to the quantum size effect. Raman studies showed shifting and broadening of the peaks of TiO2 QDs due to the reduction of the crystallite size. The obtained Brunauer–Emmett–Teller specific surface area (381 m2 g−1) of TiO2 QDs is greater than the surface area (181 m2 g−1) of commercial TiO2 nanoparticles. The photocatalytic activities of TiO2 QDs were conducted by the inactivation of Escherichia coli under ultraviolet light irradiation and compared with commercially available anatase TiO2 nanoparticles. The photocatalytic inactivation ability of E. coli was estimated to be 91% at 60 µg ml−1 for TiO2 QDs, which is superior to the commercial TiO2 nanoparticles. Hence, the present study provides new insight into the rapid synthesis of TiO2 QDs without any annealing treatment to increase the absorbance of ultraviolet light for superior photocatalytic inactivation ability of E. coli.

Doping processes for optical materials are one of the driving forces for developing efficient and clean technologies for decontamination of aquatic effluents through lowering their band gap energy to become effective in sunlight. The current study has used a non-conventional technique for doping zinc oxide by multi metals, non-metals and organic dyes through a one-step process. In this trend, Zn-Al nanolayered structures have been used as hosts for building host–guest interactions. Organic dyes that have inorganic species of iron, nitrogen and sulfur have been used as guests in the intercalation reactions of Zn-Al layered double hydroxides. By intercalating green dyes, organic–inorganic nanohybrids were formed as nanolayered structures with expanding interlayered spacing to 2.1 nm. By changing the concentration of green dyes and thermal treatment, series of nanofibers and nanoplates of zinc oxides were formed and doped by aluminum, iron and sulfur in addition to colored species. The optical properties of the multi-doped zinc oxide indicated that it became suitable for solar applications because its band gap energy decreased from 3.30 eV to 2.80 eV. The experimental and kinetic results of the multi-doped zinc oxide concluded that the colored pollutants were effectively removed during 50 min of sunlight irradiation.

In this work, we report a new approach for detecting SARS-CoV-2 RBD protein (RBD) using the surface-enhanced Raman spectroscopy (SERS) technique. The optical enhancement was obtained thanks to the preparation of nanostructured Ag/Au substrates. Fabricated Au/Ag nanostructures were used in the SERS experiment for RBD protein detection. SERS substrates show higher capabilities and sensitivity to detect RBD protein in a short time (3 s) and with very low power. We were able to push the detection limit of proteins to a single protein detection level of 1 pM. The latter is equivalent to 1 fM as a detection limit of viruses. Additionally, we have shown that the SERS technique was useful to figure out the presence of RBD protein on antibody functionalized substrates. In this case, the SERS detection was based on protein-antibody recognition, which led to shifts in the Raman peaks and allowed signal discrimination between RBD and other targets such as Bovine serum albumin (BSA) protein. A perfect agreement between a 3D simulated model based on finite element method and experiment was reported confirming the SERS frequency shift potential for trace proteins detection. Our results could open the way to develop a new prototype based on SERS sensitivity and selectivity for rapid detection at a very low concentration of virus and even at a single protein level.

The present study aims to enhance the optical properties of barium titanate through narrowing its band gap energy to be effective for photocatalytic reactions in sunlight and be useful for solar cells. This target was achieved through growth of the hollandite phase instead of the perovskite phase inside the barium titanate crystals. By using solvent thermal reactions and thermal treatment at different temperatures (250 °C, 600 °C, and 900 °C), the hollandite phase of barium titanate was successfully obtained and confirmed through X-ray diffraction (XRD), Raman spectra and scanning electron microscopy techniques. XRD patterns showed a clear hollandite phase of barium titanium oxides for the sample calcined at 900 °C (BT1-900); however, the samples at 600 °C showed the presence of mixed phases. The mean crystallite size of the BT1-900 sample was found to be 38 nm. Morphological images revealed that the hollandite phase of barium titanate consisted of a mixed morphology of spheres and sheet-like features. The optical properties of barium titanate showed that its absorption edge shifted to the visible region and indicated band gap energy tuning ranging from 1.75 eV to 2.3 eV. Photocatalytic studies showed the complete and fast decolorization and mineralization of green pollutants (naphthol green B; NGB) in the prepared barium titanate with hollandite phase after illumination in sunlight for ten minutes. Finally, it can be concluded that the low band gap energy of barium titanate having the hollandite phase introduces beneficial structures for optical applications in sunlight.

The high risk of morbidity and mortality associated with SARS-CoV-2 has accelerated the development of many potential vaccines. However, these vaccines are designed against SARS-CoV-2 isolated in Wuhan, China, and thereby may not be effective against other SARS-CoV-2 variants such as the United Kingdom variant (VUI-202012/01). The UK SARS-CoV-2 variant possesses D614G mutation in the Spike protein, which impart it a high rate of infection. Therefore, newer strategies are warranted to design novel vaccines and drug candidates specifically designed against the mutated forms of SARS-CoV-2. One such strategy is to target ACE2 (angiotensin-converting enzyme2)–Spike protein RBD (receptor binding domain) interaction. Here, we generated a homology model of Spike protein RBD of SARS-CoV-2 UK strain and screened a marine seaweed database employing different computational approaches. On the basis of high-throughput virtual screening, standard precision, and extra precision molecular docking, we identified BE011 (Dieckol) as the most potent compounds against RBD. However, Dieckol did not display drug-like properties, and thus different derivatives of it were generated in silico and evaluated for binding potential and drug-like properties. One Dieckol derivative (DK07) displayed good binding affinity for RBD along with acceptable physicochemical, pharmacokinetic, drug-likeness, and ADMET properties. Analysis of the RBD–DK07 interaction suggested the formation of hydrogen bonds, electrostatic interactions, and hydrophobic interactions with key residues mediating the ACE2–RBD interaction. Molecular dynamics simulation confirmed the stability of the RBD–DK07 complex. Free energy calculations suggested the primary role of electrostatic and Van der Waals’ interaction in stabilizing the RBD–DK07 complex. Thus, DK07 may be developed as a potential inhibitor of the RBD–ACE2 interaction. However, these results warrant further validation by in vitro and in vivo studies.

La2/3Cu3Ti4O12 (LCTO) powder has been synthesized by the mechanochemical milling technique. The pelletized powder was conventionally sintered for 10 h at a temperature range of 975–1025 °C, which is a lower temperature process compared to the standard solid-state reaction. X-ray diffraction analysis revealed a cubic phase for the current LCTO ceramics. The grain size of the sintered ceramics was found to increase from 1.5 ± 0.5 to 2.3 ± 0.5 μm with an increase in sintering temperature from 975 to 1025 °C. The impedance results show that the grain conductivity is more than three orders of magnitude larger than the grain boundary conductivity for LCTO ceramics. All the samples showed a giant dielectric constant (1.7 × 103–3.4 × 103) and dielectric loss (0.09–0.17) at 300 K and 10 kHz. The giant dielectric constant of the current samples was attributed to the effect of internal barrier layer capacitances due to their electrically inhomogeneous structure.

In the present work, we studied the effects of substitutional Sm3+ ions on the ionic conduction properties of Li5+2xLa3Nb2−xSmxO12 (LLN-Sm) ceramics with x = 0.0—0.6. The investigated final ceramics, prepared by solid state reaction, were sintered at 1000 °C for 12 h. XRD investigations showed the formation of the cubic garnet phase for all of the studied samples. The ionic conductivity was found to increase with Sm3+ content, with the highest value of 7.04 × 10−5 S/cm for the Li5+2xLa3Nb2−xSmxO12 sample compared to 7.49 × 10−6 S/cm for the pure LLN sample, both at RT. Lithium ion mobilities of LLN-Sm garnets at different temperatures were estimated. Considerable enhancement of mobility, the main factor leading to ionic conductivity improvement, was obtained for samples with Sm3+ substitutions. Relaxation processes were studied by the electric modulus, and the corresponding activation energy was found to be very similar to the ionic conduction process.

CaCu3Ti4-x((A0.05Nb0.05))xO12 ceramics (A: Al and Bi; x = 0, 0.3) were synthesized by high-energy mechanical ball milling and reactive sintering at 1050 °C in air. Rietveld refinement of XRD data revealed the pure and (Al3+, Nb5+) cosubstituted ceramics contained a minor CuO secondary phase with a mole fraction of about 3.2% and 6.9%, respectively, along with a CaCu3Ti4O12 (CCTO)-like cubic structure. In addition, (Bi3+, Nb5+) cosubstituted ceramics had a pyrochlore (Ca2(Ti, Nb)2O7) secondary phase of about 18%. While the (Al3+, Nb5+) cosubstituted CCTO showed the highest relative permittivity (ε’ = 3.9 × 104), pure CCTO showed the lowest dielectric loss (tanδ = 0.023) at 1 kHz and 300 K. Impedance-spectroscopy (IS) measurements showed an electrically heterogeneous structure for the studied ceramics, where a semiconducting grain was surrounded by highly resistive grain boundary. The giant relative permittivity of the ceramics was attributed to the Maxwell–Wagner polarization effect at the blocking grain boundaries and domain boundaries. The higher tanδ of the cosubstituted samples was correlated with their lower grain boundary’s resistivity, as confirmed by IS analysis. Modulus-spectrum analysis revealed two relaxation processes for the pure and (Bi3+, Nb5+) cosubstituted CCTO samples. Dissimilar behavior was observed for the (Al3+, Nb5+) cosubstituted CCTO, where three relaxation mechanisms were observed and attributed to the grain, domain-boundary, and grain-boundary responses.

The presence of heavy metals in increased concentrations in the environment has become a global environmental concern. This rapid increase in heavy metals in the environment is attributed to enhanced industrial and mining activities. Metal ions possess a lengthy half-life and property to bioaccumulate, are non-biodegradable and, thus, are a threat to the human health. A number of conventional spectroscopic and chromatographic techniques are being used for the detection of heavy metals, but these suffer from various limitations. Nano-based sensors have emerged as potential candidates for the sensitive and selective detection of heavy metals. Thus, the present study was focused on the synthesis of selenium nanoparticles (SeNPs) by using selenite-reducing bacteria in the development of a heavy metal toxicity biosensor. During the biosynthesis of selenium nanoparticles, supernatants of the overnight-grown culture were treated with Na2SeO32− and incubated for 24 h at 37 °C. The as-synthesized nanoparticles were characterized by UV–Vis spectroscopy, X-ray diffraction (XRD), Fourier transform infrared (FTIR) and transmission electron microscopy (TEM) analyses. XRD and TEM results confirmed the formation of SeNPs in sizes ranging from 35 to 40 nm, with face-centered cubic (FCC) structures. The bioreduction process and validation of the formation of SeNPs was further confirmed by FTIR studies. The reduction in the biosynthesis of SeNPs using bacterial metabolite due to heavy metal cytotoxicity was analyzed by the colorimetric bioassay (SE Assay). The inhibition of selenite reduction and loss of red color in the presence of heavy metals may serve as a biosensor for heavy metal toxicity analysis. Thus, this biosensor development is aimed at improving the sensitivity and specificity of analytic detection.

Vertical Agx/TiO2 nanorods were successfully grown by a simple oxidation method of a Ti-Ag coating. The samples were grown in the phase of ceramic-like materials, which can be reusable for many cycles for photocatalysis applications. These ceramic-like Agx/TiO2 nanostructures were prepared by the spin-coating of silver nitrate onto Ti sheets. The presence of silver on the surface of the Ti sheet during the oxidation process helped in the growth of one-dimensional nanostructures. The physical properties of the fabricated ceramic-like nanostructures were studied by varying the concentration of silver on the Ti-sheet before the oxidation. One-dimensional nanostructures with an average size varying within the range of 200–500 nm were grown. The presence of silver made the nanostructure vertically directed. The nanorods were dense at the low and medium concentrations of 5, 10, and 20 mM of silver in contrary to high silver concentrations, where the nanorods were very sparse at 40 mM. Structural analysis showed the anatase and rutile structure of pure TiO2 with distinguishing diffraction lines A(101) and R(110); however, Agx/TiO2 showed a dominant orientation of A(101), confirming the 1D growth. Raman spectra confirmed the presence of TiO2 via the observation of its corresponding phonon modes. The photocatalysis properties of the fabricated ceramic-like nanostructures were performed on methylene blue (MB) as a known target dye. The low- and medium-silver-concentration samples showed a high photocatalytic activity compared to the pure and high-silver-concentration samples.