Band 238, Heft 11 - Special Issue: Solar Water Splitting And Artificial Photosynthesis (SWAP), Part 2; Guest Editors: Kevin Bethke, Jeyanthinath Mayandi and Smagul Karazhanov

Developing a robust material holding antimicrobial assets has been an efficient strategy for reducing the risk of infections related to healthcare, significantly with medical devices and touch surfaces. Molybdenum-based compounds have drawn momentous attraction because of their unique characteristics. A series of undoped and 5 % rare earth (Ce & La) doped metal (Ni, Co & Bi) molybdate nanocomposites have been prepared by facile microwave combustion method and characterized. The present study investigates the effect of dopants on crystal structure and morphology, and their impact on anti-bacterial properties is noticed. The UV–Vis. absorption spectra of all samples show a broad absorption band between 280 and 430 nm. The antibacterial properties of the prepared nanocomposites have been examined by the agar diffusion method against three Gram-positive and two Gram-negative bacteria, showing good bactericidal efficiency for all samples, except 5 % Ce–NiMoO 4 (antibacterial activity exclusively against Gram-positive bacteria) and 5 % La–NiMoO 4 (no antibacterial activity) nanocomposites. This work provided a novel pathway in the biomaterial field.

The structural, morphological, magnetic, and dielectric properties of lanthanum substituted nickel ferrite (NiLa x Fe 2− x O 4 ) nanoparticles have been reported in this article. The amount of lanthanum substitution in NiLa x Fe 2− x O 4 sample was varied from x  = 0.025 to 0.125. The nanocrystalline Ni–La ferrites were synthesized using a solution combustion reaction (SCR) method. The orthorhombic crystal system of space group Pnma (62) is shown as the single-phase in all samples through structural investigation utilizing an X-ray diffraction (XRD) pattern. The observed trend indicates a positive correlation between the concentration of La and the corresponding rise in the predicted crystallite size values, which range from 60.5 nm to 65.2 nm. The nanoscale of the surface morphology has been confirmed by the utilisation of field emission scanning electron microscopy (FESEM). Energy dispersive X-ray (EDAX) mapping provides the compositional evidence for the prepared Ni–La ferrites. In addition, X-ray photoelectron spectroscopy (XPS) determines the ionic state of the individual atoms present in these samples. It reveals that there are no changes in the ionic state of the parent component atoms by substituting La. EDAX and XPS evidence the purity of prepared NiLa x Fe 2− x O 4 samples without any other impurity elements. By regulating the composition of dopants, this research can substantiate the superparamagnetic characteristics of ferrites. The paramagnetic nature of lanthanum atoms involves in reducing the coercivity value. The dielectric measurement on NiLa x Fe 2− x O 4 samples reveals that La 3+ substitution effectively influence the electro-transport properties.

This study aims to explore the relationship between dust accumulation on a glass and various environmental factors including temperature, humidity, atmospheric pressure, and wind speed. The data was analyzed using Python, a popular language for data science and artificial intelligence, and regression algorithms from the scikit-learn library. The data was divided into training (80 %) and test (20 %) sets and different models were used, such as linear regression, decision tree, K-neighbor regression, random forest regression, and decision tree regression. The accuracy of the models was determined using R 2 scores, where a score of 1.0 indicates a perfect fit and negative values suggest that the model is worse than predicting the mean value. The accuracy of the selected models was calculated as a percentage by multiplying the obtained R 2 scores by 100. Graphs were used to visualise the data and determine the appropriate analysis model. The study found that the amount of dust is directly proportional to temperature and humidity. The accuracy levels of the linear models were suboptimal, leading to the use of nonlinear models like random forest regressor, decision tree regressor, and gradient boosting regressor, which showed improved performance.

A novel organic-inorganic photocatalyst like layer structured graphitic carbon nitride (g-C 3 N 4 or CN) hybrid with strontium titanate (SrTiO 3 or STO) was prepared by a precipitation-sonication technique for photocatalytic activity. The crystal phases, morphologies, elemental composition, optical properties, and porous structure of the prepared pristine and STO/CN hybrid composite were measured using various physicochemical characterizations. It is indicated that STO nanospheres were effectively loaded on the g-C 3 N 4 nanosheets, resulting in the STO/CN hybrid composite, high surface area, enhanced visible-light absorption, enhancing photoinduced charge separation and suppressing the recombination rate. Furthermore, the 3 wt% of g-C 3 N 4 composited STO (STO/CN-3) catalyst demonstrated higher photocatalytic activity than pristine STO in 100 min under white light irradiation, reaching the degradation efficiency of 92.66 % and 93.31 % toward methylene blue (MB) and tetracycline (TC), respectively. The improved photocatalytic activity of STO/gCN hybrid composite could be ascribed to the synergistic effect between STO and CN with strong interfacial interaction facilitating efficient charge separation and inhibiting the charge recombination of photogenerated electron-hole pairs. Moreover, a possible photocatalytic mechanism has been proposed for the degradation of MB and TC. Besides, the excellent photocatalytic performance, STO/CN-3 nanocomposite also exhibits outstanding photostability under the current factors, suggesting that they are suitable for practical applications.

Clay and clay-based minerals have attracted research attention because of their unique properties and a vast range of applications in industry. In order to assess the potential applications, four different processed local kaolin-based raw minerals were collected from the Aral Sea region of Uzbekistan, and the total mineralogical properties have been explored. The results reveal that the structural, vibrational and electronic properties of metakaolinites only slightly differ from those of kaoline. The presence of corundum, quartz and kaolinite structural phase in minerals was determined by XRD analysis. FTIR and Raman studies expose the primary peaks which are associated with the functional groups of Al–OH, Al–O and Si–O in higher-frequency stretching and lower-frequency bending modes. The elemental and chemical compositional (XRF and XPS) analysis demonstrates the presence of major elements (Al, Si, Na, Fe, Ti) in the raw mineral and other metal contaminations (Mg, Ca, S, Cr, Zr). The SEM analysis demonstrates the morphological nature of kaolin-based raw minerals that can be exploited for industrial purposes.

We investigate the effective oxidation state and local environment of yttrium in photochromic YHO thin film structures produced by e-beam evaporation, along with their chemical structure and optical properties. Transmission electron microscopy images reveal the oxidized yttrium hydride thin film sample exhibiting a three-layered structure. X-ray photoelectron spectroscopy (XPS) measurements manifest that the oxidation state of yttrium is modified, dependent on the film’s composition/depth. Furthermore, Ion beam analysis confirms that this variability is associated with a composition gradient within the film. X-ray absorption spectroscopy at the Y K-edge reveals that the effective oxidation state of yttrium is approximately +2.5 in the transparent/bleached state of YHO. Spectroscopic ellipsometry investigations showed a complex non-linear optical depth profile of the related sample confirming the dominant phase of YHO and the presence of Y 2 O 3 and Y towards the middle of the film. The first evidence of ( n ; k ) dispersion curves for e-beam sputtered photochromic YHO thin films are reported for transparent and dark states.

Single crystals of barium bis para -Nitrophenolate para -Nitrophenol tetrahydrate (BBPNT) were grown via the slow evaporation technique. The crystal dimensions were measured to be 15 mm × 10 mm × 6 mm. The BBPNT crystal was analyzed using X-ray diffraction, FTIR spectrum, UV–vis spectrum, dielectric studies, thermo-gravimetric (TG) differential thermal analyses (DTA), Vickers microhardness test, second-harmonic generation efficiency, Z-scan technique, PL spectra, and laser damage threshold studies. These findings were previously published in our paper. In the current situation, the theoretical methods include analyzing several aspects, such as the molecular structure determined using X-ray experimentation at its lowest energy state. This analysis is then contrasted by means of density functional theory (DFT) with a suitable set of basic functions. The first-order hyperpolarizability may also be determined via the use of Density Functional Theory (DFT) methods. The molecule’s stability, resulting from hyper conjugative interactions, was examined using the natural bond orbital approach to analyses its nonlinear optical activity and charge delocalization. The magnitude of the HOMO–LUMO energy gap indicates the potential for charge transfer inside the molecule. The investigation of donor-acceptor interactions was conducted using NBO analysis based on optimized ground state geometries.

A bulk organic single crystal of phenothiazine measuring 65 mm in length and 10 mm in width was grown using the single zone vertical Bridgman technique (VBT), which was visible to the naked eye. Powder X-ray diffraction, also known as XRD, was used in order to perform crystal structural verification on the manufactured crystal. The Fourier transform infrared spectroscopy (FT-IR) approach was used in order to ascertain the crystals’ respective vibrational frequencies. In order to evaluate the single crystal’s crystalline perfection and optical quality, high-resolution X-ray diffraction rocking curve measurement (HRXRD) and UV transmittance spectrum analysis were used. So as to investigate the nonlinear optical (NLO) activity of the generated single crystals, a Q-switched and pulsed Nd: YAG laser was used in the research. This led to the discovery of the SHG efficiency. The single crystal’s mechanical strength was evaluated using Vicker’s microhardness measurement, which provided an approximation of the true value. Furthermore, the single crystal was examined and reported for its optical birefringence, photoluminescence, and refractive index.

In recent decades, nanomedicine has attracted much attention at the forefront of nanotechnology, gaining great expectations in the biomedical sectors. Among various nanomaterials, silica nanoparticles-based drug delivery is considered effective owing to their physicochemical stability and biological compatibility. Surface grafting and chemical conversion techniques were used to create an amphoteric functional ligand known as amidoxime ligand (AL) modified mesoporous silica material (MS-AL NPs). With this technique, amidoxime ligand groups can be introduced in greater concentration to the silica surface without compromising its structure. The active surface allows for surface functionalization and integration of medicinal substances. They are widely employed in the bio-medical industry for diagnostics, target administration of drugs, bio-sensing, cellular absorption, and so on. The function of the produced MS-AL NPs as a regulated drug delivery system was studied utilizing doxorubicin (Dox) as a model anticancer drug. Using the MCF-7 cell line, the biocompatibility and cellular uptake characteristics were investigated. Considering all factors, the MS-AL NPs may be used as pH-responsive drug carriers in cancer treatment applications.

Thulium selenite (TmSeO 3 ) has been synthesized by precipitation method. It shows interesting smooth surface with nearly non-symmetric texture similar to water droplets spreading on hydrophobic surface. TmSeO 3 is found to be monoclinic structure with lattice parameters a  = 5.919±0.01 Å, b  = 12.422±0.01 Å, c  = 8.717±0.01 Å, α  =  γ  = 90°, β  = 106.01° and V  = 616.1 Å 3 . Fourier transform infrared spectroscopy confirms the presence of Tm–Se bonding. X-ray photo emission spectrum confirmed the presence of thulium, selenium and oxygen in the samples in oxide form. Magnetic study between 300 and 20 K, shows decrease of magnetic moment with temperature, then reaches saturation and aligns all thulium spins. This results cooperative interaction of thulium spins. M – H curve at 300 K confirms the paramagnetic nature of sample. Cyclic voltammogram of three electrode system, manifests electric double layer capacitance with a potential window of 0.55 V. Specific capacitance is 102 F/g. Chronopotentiometry analysis shows 75 F/g specific capacitance, 11 Wh kg −1 energy density, and 275 W kg −1 power density. Impedance analysis confirms electric double layer capacitor behavior. Hence, TmSeO 3 electrode based symmetric supercapacitor device was successfully fabricated and tested by two electrode configuration in aqueous electrolyte of KOH. A specific capacitance of 64.60 F/g at 1 A/g within a potential window of 1.85 V was achieved. Impedance analysis also confirms electric double layer capacitor nature with low series resistance of 0.2596 Ω and charge transfer resistance of 1.6352 Ω. The improved cycling performance after 4000 cycles is 51.5 % specific capacitance retention. Thus, symmetric supercapacitor electrodes based TmSeO 3 materials are expected to have good electrochemical properties and good stability for energy storage and conversion applications. Furthur, optical parameters 5.28 eV energy gap, 0.4924 eV Urbach energy value and 1.959 refractive index are determined.