Analytical Techniques Including X-ray Diffraction Research Articles

A study on structural and optical properties of the synthesized PVP capped Zinc Oxide Nanoparticles

Zinc Oxide Nanoparticles, capped with a polymer, have been effectively synthesized using a chemical precipitation method at a relatively low reaction temperature of 60 °C. The present study examines the structural and optical properties of ZnO Nanoparticles (NPs) that have been synthesized and capped with different weight percentages of PVP (Polyvinyl Pyrrolidone). To investigate these properties, advanced analytical techniques including X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FE-SEM), Ultra Violet-visible (UV–vis) absorption spectroscopy are employed. The XRD analysis reveals that the synthesized ZnO samples have a hexagonal wurzite structure, regardless of adding capping agent. The Williamson-Hall (W-H) analysis, a commonly used method, estimates the strain present in synthesized materials. The SEM image depicts ZnO NPs that have a nearly spherical form and are seen to be agglomerated. The UV–vis absorption measurements demonstrate a phenomenon known as blue shift when compared to the absorption characteristic of bulk ZnO.

Morphology-transforming AuNPs-based fluorescent probe for ultra-low sensitive detection of levofloxacin in urine samples at pH 7.0 through excimer formation

Fluorescent metal nanoparticles (MNPs) have garnered considerable interest in the realm of healthcare applications. Within this domain, we present a novel fluorescent sensor: Pamoic acid (PA) functionalized excitation-dependent gold nanoparticles (PA@AuNPs), designed to ascertain levofloxacin (LF) concentrations in human urine samples under pH 7.0 conditions. The synthesis of PA@AuNPs was achieved via a chemical reduction method employing PA as both a reducing and stabilizing agent. Validation of the successful synthesis of PA@AuNPs was conducted utilizing a suite of analytical techniques including X-ray diffraction (XRD), ultraviolet–visible absorption spectroscopy (UV–Vis), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). Microscopic examination via field emission scanning electron microscopy (FESEM) and high-resolution transmission electron microscopy (HRTEM) elucidated the spherical morphology of PA@AuNPs, with an average diameter ranging from 10 to 15 nm. Furthermore, atomic force microscopy (AFM) revealed an average surface roughness of 20.72 nm for PA@AuNPs. Thermal analysis results divulge that PA@AuNPs are highly stable up to 370 °C. The PA@AuNPs have shown more than 10-fold higher selectivity for LF in comparison with other commercially available antibiotics. The fluorescence emission intensity of PA@AuNPs (quantum yield (ΦF) 3.36 %) has shown enhanced redshift (436 → 497 nm; ∼61 nm) (λex 353 nm) upon the sequential addition of LF (0 → 100 µM) and achieved a lower detection limit (LoD = 36 nM; LoQ = 121 nM; Ka = 1.0457 × 104 M−1) with increased ΦF 18.96 %. This radiative process and fluorescence enhancement were confirmed by time-correlated single photon counting (TCSPC) measurement (4.89 → 5.36 ns). Interestingly, upon sensing LF, PA@AuNPs changed their morphology from spherical to octahedron and displayed an excimer formation through intermolecular π-π stacking. Furthermore, the stability of the complex, PA@AuNPs•LF which formed through coordination, by restoring the fluorescence intensity of PA@AuNPs•LF (turn on) in the presence of ethylenediamine tetraacetic acid (EDTA) (turn off) is demonstrated. The formation of the PA@AuNPs•LF complex was further confirmed by XRD analysis and FTIR spectroscopy. The HRTEM and FESEM validate that PA@AuNPs•LF have octahedral morphology with an average size of 20–30 nm, and the obtained moiré fringes in TEM images are due to the overlap of LF on the surface of PA@AuNPs. The AFM analysis divulges that PA@AuNPs•LF had a larger surface roughness (Sa = 26.91 nm). The experimentally attained zeta potential of PA@AuNPs (–12.6 mV) was further decreased (–17.6 mV) in the presence of LF, which confirms the interaction between PA@AuNPs and LF. The cell viability (82 %) in L929 Fibroblast cells augmented the biological applications of PA@AuNPs. The practicability of the fluorescent sensor probe was demonstrated in human urine samples with recovery ranges from 97.56 to 104.38 %.

Eco-friendly LEDs radiation-assisted photocatalytic mineralization of toxic azure B dye using Bi2MoZnO7 nanocomposite

The present time nanocomposites show highly improved photocatalytic performance in water pollution remediation technology. Herein, BMZ (Bi2MoZnO7) nanocomposite photocatalyst has been synthesized via the co-precipitation method. The structural and morphological studies were interpreted by analytical techniques including X-Ray Diffraction (XRD), Field emission scanning electron microscopy (FE-SEM), Transmission electron microscopy (TEM), and Energy Dispersive X-ray (EDX) analyses. The accomplishment of photocatalysis was determined by the mineralization of toxic azure B dye using a light-emitting diode (LED) as a source of radiation. The characterization studies revealed that the average particle size of BMZ nanocomposite was 28 nm with a flake-like structure having a smooth surface. An EDX spectrum shows the characteristic peaks of Bi, Mo, Zn, and O elements. The parameters such as pH, dye concentration, catalyst weight, reusability of photocatalyst, Fenton’s reagent, CO2, COD, NO3− and SO42− evaluation, and N2 and O2 purging were studied for optimum conditions. Fenton’s reagent test is one of the green approaches in which OH is generated that is utilized for the degradation of toxic azure B dye. The photocatalytic degradation in Fe2+/H2O2/BMZ/Azure B system, high value of the rate constant was recorded as compared to the experiments, performed without BMZ nanocomposite photocatalyst. The eco-friendly LEDs irradiation was applied as a light source material throughout the experiment. The 98 % degradation of toxic azure B dye was observed in 120 min with the highest rate constant (k = 6.1 × 10−4 s−1) in LEDs irradiation.

Valorisation of microalga Chlorella sp. into furans in the presence of Nb2O5 catalysts

Despite the interest in niobia-based catalysts and the importance of biomass valorisation, studies on these catalysts typically utilize model substrates like simple sugars. In this study, a series of niobium oxide-based catalysts was prepared for the application in aqueous phase catalytic conversion of sugars extracted from Chlorella sp. microalga into value-added furans. The solid catalysts were firstly characterized by various techniques including X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), Raman and X-ray photoelectron (XPS) spectroscopy as well as low-temperature N2 physisorption. Moreover, the acidity of the catalysts was assessed by using the temperature-programmed NH3 desorption (NH3-TPD), by titration of water suspended catalyst with NaOH solution, and by P-bearing molecular probes loaded catalysts through 31P and 1H solid-state nuclear magnetic resonance (NMR) techniques. Herein, we focused on the catalytic transformation of Chlorella sp. and glucose solution as model molecule into furans. The best Nb2O5 catalysts for valorizing Chlorella sp. into furans exhibited a larger number of Brønsted acid sites, achieving conversion yields to 5-HMF and furfural of ca. 20–22 % with respect to the extracted sugars from algae. The results showed a discernible dependence of the conversion yields to 5-HMF and furfural on catalyst acidity, specific surface area, and the presence of the Brønsted acid sites. Conversely, when using the glucose solution as substrate is concerning, the highest yield to 5-HMF was reached by using a catalyst that showed also the presence of Lewis acid sites. A systematic investigation of the structure–activity relationships in niobium oxide application for aqueous phase dehydration using real biomass substrates to obtain furanic derivatives has not been documented thus far. Therefore, the current research is significant as it demonstrates the feasibility of transforming the carbohydrate content in microalgal biomass into furans by identifying the best catalyst to use.

A comparative study between the use of nanoparticles of magnesium oxide and zinc oxide as coating for polymeric surfaces a flame retardant and corrosion resistance

This study deals with the preparation of magnesium oxide nanoparticles (MgO NPs) and zinc oxide nanoparticles (ZnO NPs) by the co-precipitation method. The prepared metal oxide was characterized by X-ray diffraction analysis, scanning electron microscope, transmission electron microscope, element analysis examination, and UV–Visible and IR spectroscopies. The results of these tests showed the nano size, uniform distribution, and purity of the prepared powders. They proved the appearance of cubic and hexagonal phases of MgO NPs and ZnO NPs, respectively. These NPs have 4.2 eV and 3.12 eV energy gap values, respectively. The preparation of a coating consisting of MgO NPs and ZnO NPs involves combining them separately with epoxy in ratios of 3 %, 6 %, and 9 %. This mixture is then used to cover the polymeric surface using the immersion method. The nanocomposites have been examined before and after applying a coating via different techniques including X-ray diffraction analysis, infrared spectrum, atomic force microscopy, combustion test, thermal gravimetric decomposition, thermal conductivity, corrosion rate, hardness, and tensile strength. According to the results, it is found that the immersion coating method gives good dispersion of the NPs within the polymer matrix. Moreover. When comparing the use of MgO NPs and ZnO NPs, it is found that the use MgO NPs has given better results for flame retardancy, thermal gravimetric analysis and reduction of corrosion compared to the use of ZnO NPs, which has given better mechanical properties and thermal conductivity than MgO.

Easy access to strongly fluorescent higher homologues of BODIPY.

We present the easy and high yield synthesis of several group 13 MesDPM compounds (Al-In) with alkyl substituents at the metal atom. All these compounds were fully characterized using techniques including X-ray diffraction analysis and photoluminescence measurements. It shows that for aluminium and gallium pronounced green fluorescence is observed, which is absent for indium. DFT calculations confirm that the first electronic transition corresponds to a ligand-based π-π* transition.

Reducing oil absorption in pea starch through two-step annealing with varying temperatures

In this study, we investigated the effects of one-step and two-step annealing on pea starch (PS) and their impact on the starch structure and oil absorption following frying. Compared to native PS, both one-step and two-step annealing treatments significantly reduced starch solubility, swelling power, oil absorption, and specific surface area while increasing water absorption. The extent of these changes depended on the specific annealing parameters applied. Notably, among all the starch samples, PS-45-55-F (PS subject to two-step annealing at 45 °C and then 55 °C, followed by frying) exhibited the lowest oil absorption. Scanning electron microscopy (SEM) results revealed that PS-45-F (PS subject to one-step annealing at 45 °C, followed by frying) and PS-45-55-F retained more of the original starch structure after frying. Analytical techniques including X-ray diffraction (XRD), Fourier-transform infrared (FT-IR), and differential scanning calorimetry (DSC) consistently indicate that two-step annealed starch (PS-45-55-F) better preserved both long-range and short-range ordered structure of starch granules during frying. Additionally, it enhanced the thermostability of annealed starch, making it more effective in inhibiting oil absorption. These findings highlight the potential of two-step annealed starch for the development of low-oil, high-quality, and healthy fried or pre-fried food products, such as coated fried chicken and tempura.

Enhancing Photocatalytic Activity of Bismuth Ferrite (BiFeO3) via Gadolinium and Copper Doping: A Sol-Gel Synthesis and Characterization Study

In this current research work, the sol-gel method was employed to synthesise, characterize and evaluate the photocatalytic activity of bismuth ferrite (BiFeO3, BFO) doped with two distinctive components consisting of a rare earth element Gadolinium (Gd) and a transition metal Copper (Cu). The dopant concentrations were systematically varied with different weight percentages (wt.%) denoted as Bi1-xGdxFe1-yCuyO3 (where ‘x’ = 0.10, 0.15 and 0.20 wt.%, where ‘y’ = 0.05, 0.10, and 0.15 wt.%). Subsequently, characterizations of the prepared samples were conducted using an array of cutting-edge analytical techniques including X-ray diffraction (XRD), filed emission scanning electron microscopy (FE-SEM), energy dispersive X-ray analysis (EDAX), and transmission electron microscopy (TEM). The XRD analysis results indicated that the presence of small impurity peaks was found in both Gd-doped BFO and GdCu-doped BFO. The FE-SEM and TEM results provided confirmation that the material was observed as a spherical shape, and the elemental compositions were also confirmed through EDAX analysis. The photocatalytic degradation of Rhodamine B dye under the influence of visible light irradiation was carried out and the results revealed varying degradation times, specifically, for Gd and Cu-doped BFO (Gd and Cu = 0.1 wt.%) achieved almost 98% degradation occurred in 30 minutes.

Study on Optical of Chitosan-Aminopropyltriethoxysilane-SiO2 Nanocomposite Decorated with Carbon Nanotubes

In our study, we examined the growth of SiO2-aminopropyltriethoxysilane nanoparticles decorated with carbon nanotubes (CNTs) on a chitosan matrix. This matrix was synthesized through a sol-gel process, where chitosan was dissolved into a silicate sol and subsequently gelled at 50 °C. To explore the structure, morphology, and optical properties of these semiconductor nanocomposites, we employed various analytical techniques including X-ray diffraction (XRD), transmission electron microscopy (SEM), Fourier Transform Infrared (FT-IR) spectroscopy, and UV-vis spectroscopy. From the UV-Vis spectroscopy measurements, the absorption, band gap, refractive index, and optical conductivity were extracted and analyzed with respect to the incident wavelength and content of CNTs. The incorporation of CNTs into the chitosan-SiO2-aminopropyltriethoxysilane semiconductor nanocomposite results in enhanced crystallinity, increased surface area, and modified optical properties. Therefore, it can be inferred that the optical characteristics of the chitosan-SiO2-aminopropyltriethoxysilane composite are significantly influenced by the ratio of CNT decoration.

The structure of Maneb: An important manganese-containing bis(dithiocarbamate) fungicide.

Maneb is a manganese(II) containing fungicide with a multi-site effect and no resistance, therefore it is widely applied in many parts of the world. There is however mounting evidence for neurotoxic effects with Parkinson-like symptoms (manganism) related to usage of Maneb. Due to its insolubility in most solvents and its paramagnetism, structural elucidation is not trivial and thus its exact molecular structure remains unknown. We report herein a synthesis procedure to prepare Maneb reproducibly in pure form and the use of various analytical techniques including X-ray diffraction, X-ray absorption spectroscopy and electron diffraction to determine the molecular structure of Maneb in the solid state and also in solution.

Development of ZnO-GO-NiO membrane for removal of lead and cadmium heavy metal ions from wastewater

The presence of heavy metal (HM) ions, such as lead, cadmium, and chromium in industrial wastewater discharge are major contaminants that pose a risk to human health. These HMs should separate from the wastewater to ensure the reuse of the discharged water in the process and mitigate their environmental impacts. The distinctive mechanical properties of 2D graphene oxide (GO), and the antifouling characteristics of metal oxides (ZnO/NiO) nanoparticles combined to produce composites supporting special features for wastewater treatment. This study employed solution casting and phase inversion methods to synthesize PSF-based GO, ZnO-GO, and ZnO-GO-NiO mixed matrix membranes and the effects of variation in composition on the removal of lead (Pb2+) and cadmium (Cd2+) ion was examined. Several characterization techniques including X-ray diffraction analysis, scanning electron microscopy, energy dispersive X-ray, and Fourier transform infrared spectroscopy were applied to analyze the synthesized NPs and MMMs. The composite membranes were also analyzed in terms of their porosity, permeability, hydrophilicity, surface roughness, zeta potential, thermal stability, mechanical strength, and flux regeneration at various transmembrane pressures (2–3 kgcm−2), and pH value (5.5). The highest adsorption capacities were measured to be 308.16 mg g−1 and 354.80 mg g−1 for Pb (II) and Cd (II), respectively, for membrane (M4_A) having 0.3 wt% of ZnO-GO-NiO nanocomposite, at 200 mg L−1 of feed concentration and 1.60 mL min−1 of permeate flux. The Pb (II) and Cd (II) adsorption breakthrough curves were created, and the results of the experiment were compared with the data of the Thomas model.

Optical and structural properties of H-BN@Gd2O3 nanoflake prepared by laser–induced ablation in liquid

In this paper, we reported the synthesis of hexagonal BN, Gd2O3 nanoparticles, and BN@Gd2O3 hybrid nanocomposites by novel laser ablation in liquid. Several analytical techniques including x-ray diffraction (XRD), UV–vis spectroscopy, Fluorescence spectroscopy, Field Emission Scanning electron Microscopy (FE-SEM) with Energy dispersive spectroscopy (EDS), High-resolution transmission electron microscope (HR-TEM), and map imaging were used to investigate the structural and optical properties of synthesized nanoparticles. According to FE-SEM and TEM results, FE-SEM images show the formation of h-BN NPs, sheet-like, and spherical nanoparticles, hexagonal-type nanoflake of Gd2O3, and needle-like shapes. High-resolution transmission electron microscopy images confirm that the average diameter of all samples is ∼40 nm. However, the length of the nanorods is found to vary from 50 nm to 240 nm. The optical properties studies show that the optical energy gap of h-BN, Gd2O3, and h-BN@Gd2O3 is in the range of (4.5–5.5) eV.

Multi-stage precipitation for the eco-friendly treatment of phosphogypsum leachates using hybrid alkaline reagents

The leachate of waste phosphogypsum (PG) contains substantial amounts of phosphate, sulfate, and fluoride, which poses an immense threat to the safety of the aquatic ecosystem. In this study, a multi-stage precipitation approach is proposed to treat PG leachates using hybrid alkaline reagents including barium hydroxide (Ba(OH)2) and quicklime (CaO). To avoid potential environmental impacts, hazardous environmental contaminants are removed from the PG leachates by adding alkaline reagents in a specific order. The multi-stage precipitation approach achieves nearly 100% removal efficiencies for phosphate, fluoride, and metal ions as well as satisfactory removal efficiencies for sulfate and ammonia nitrogen (93.6% and 94.8% respectively). The compositions of generated mineral precipitates are comprehensively investigated by analytical techniques including X-ray diffraction (XRD), transmission electron microscope (TEM), etc. The main precipitated mineral phases are barite (BaSO4), brushite (CaHPO4·2H2O), and hydroxyapatite (Ca5(PO4)3OH). This is further proven by the geochemical modeling using Visual MINTEQ, in which the precipitation of mineral phases is calculated. Furthermore, a straightforward economic analysis indicates the proposed method has a lower cost of the use of alkaline reagents. Overall, this study establishes an effective and eco-friendly approach for the treatment of waste PG leachates to remove hazardous environmental contaminants and recover valuable precipitates.

Visible light induced photocatalytic activity of MnO2/BiVO4 for the degradation of organic dye and tetracycline

In this work, α-MnO2/BiVO4 nanocomposites with varying MnO2 contents (0–7 wt%) were successfully prepared via the simple chemical method. The structure, morphology, and optical properties of prepared nanocomposites were studied by various analytical techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), UV–visible absorption spectroscopy, and photoluminescence (PL) spectroscopy. The photocatalytic efficiency of α-MnO2/BiVO4 nanocomposites was studied via decomposition of rhodamine B (RhB) and tetracycline (TC) under exposure to visible light (λ ≥ 420 nm). Due to good structure and composite advantages, 5%MnO2/BiVO4 (MnBV-5) photocatalyst exhibited superior RhB and TC degradation efficiency to all other samples. In addition, the MnBV-5 photocatalyst showed good stability, and no apparent reduction in photocatalysis efficiency was noted after five testing cycles. Therefore, the MnO2/BiVO4 nanocomposite demonstrated a good potential for photocatalytic decomposition of new water contaminants.

Direct interfacial growth of Sr–CeO2 nanoparticles on carbon nanofibers and their multidisciplinary applications

Cerium oxide (CeO2) and carbon nanofibers (CNF) based material have been widely used for supercapcitor, optoelectronic as well and electrochemical sensor applications due to their interesting physicochemical properties. Present article reports the facile hydrothermal synthesis of Sr–CeO2/CNF electrode material under subcritical reaction conditions. Different analytical techniques including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), UV–Visible spectroscopy, X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET), Scanning electron microscopy (SEM), Energy dispersive X-ray spectroscopy (EDX), and Transmission electron microscopy (TEM) were used for the chractrization of nanocomposite. XRD and XPS results confirm the formation of Sr–CeO2/CNF having cubic fluorite structure. In addition, morphological studies shows formation of dot like morphology of Sr–CeO2 nanoparticals embedded on CNF nanorods. Surface area analysis indicated that synthesized material is mesoporous in nature and exhibited high surface area of 38.45 m2/g. The optical absorption concludes that the band gap values lies between 2.1 and 3.15 eV, suitable for optoelectronic applications. Moreover, the electrochemical study of 5 wt% Sr–CeO2/CNF exhibits substantial specific capacitance of 192 Fg-1 with 95.4% good cyclic stability at 5000 cycles. The composite electrode exhibit energy density and power density of 96 WhKg−1and 1440 WKg−1at 0.8 Ag-1 current density suggesting a good electrode material for supercapacitor. Finally, the nanocomposite was also studied for cyclic voltammetric electrochemical detection of Harmaline (HAR) showing good sensitivity with Limit of detection (LOD) and Limit of quantification (LOQ) of 0.82 μg mL−1 and 2.48 μg mL−1 respectively.

Insight into Nano-chemical Enhanced Oil Recovery from Carbonate Reservoirs Using Environmentally Friendly Nanomaterials.

The use of nanoparticles (NPs) in enhanced oil recovery (EOR) processes is very effective in reducing the interfacial tension (IFT) and surface tension (ST) and altering the wettability of reservoir rocks. The main purpose of this study was to use the newly synthesized nanocomposites (KCl/SiO2/Xanthan NCs) in EOR applications. Several analytical techniques including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscope (SEM) were applied to confirm the validity of the synthesized NCs. From the synthesized NCs, nanofluids were prepared at different concentrations of 100–2000 ppm and characterized using electrical conductivity, IFT, and ST measurements. From the obtained results, it can be observed that 1000 ppm is the optimal concentration of the synthesized NCs that had the best performance in EOR applications. The nanofluid with 1000 ppm KCl/SiO2/Xanthan NCs enabled reducing the IFT and ST from 33 and 70 to 29 and 40 mN/m, respectively. However, the contact angle was highly decreased under the influence of the same nanofluid to 41° and the oil recovery improved by an extra 17.05% OOIP. To sum up, KCl/SiO2/Xanthan NCs proved highly effective in altering the wettability of rocks from oil-wet to water-wet and increasing the cumulative oil production.

Co-precipitation synthesis of non-cytotoxic and magnetic cobalt ferrite nanoparticles for purging heavy metal from the aqueous medium: Pb(II) adsorption isotherms and kinetics study

ABSTRACT Owing to unique physical and chemical properties, nanostructured magnetic materials have proved their efficacy in treating heavy metals from the aqueous system. In this study, oleic acid-coated cobalt ferrite is synthesised by the co-precipitation method for the remediation of Pb(II) ions from an aqueous solution. The synthesised CoFe2O4@OA was characterised by various analytical techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), vibrating sample magnetometry (VSM), Fourier transform infrared spectroscopy (FT-IR) and dynamic light scattering (DLS). The non-cytotoxic behaviour of CoFe2O4@OA suggests it a risk-free adsorbent for the aquatic environment. The mechanism of adsorption reveals that electrostatic interaction, inner-sphere complex formation within Pb(II) ions and CoFe2O4@OA are responsible for the removal. The kinetics experiment followed the pseudo-second-order model with a regression coefficient (R 2) of 0.999. In the isothermal study, equilibrium data were well tuned with the Langmuir isotherm model with a maximum adsorption capacity of 16.7 mg g−1. The desorption experiment with a series of acid (HCl, HNO3) and alkali (NaOH, KOH) solvents informs the high dependency of desorption efficiency on the solvent type and concentration. Pb(II) ions removal efficiency using 0.5M HCL and 0.6M NaOH was attainted 98% and 82%, respectively, after three cycles. Thus, CoFe2O4@OA maintains sustainable development by reusing and saving the aquatic ecosystem by eliminating Pb(II) ions.

Biogenic Synthesis of CuO, ZnO, and CuO-ZnO Nanoparticles Using Leaf Extracts of Dovyalis caffra and Their Biological Properties.

Biogenic metal oxide nanoparticles (NPs) have emerged as a useful tool in biology due to their biocompatibility properties with most biological systems. In this study, we report the synthesis of copper oxide (CuO), zinc oxide (ZnO) nanoparticles (NPs), and their nanocomposite (CuO–ZnO) prepared using the phytochemical extracts from the leaves of Dovyalis caffra (kei apple). The physicochemical properties of these nanomaterials were established using some characterization techniques including X-ray diffraction analysis (XRD), ultraviolet-visible spectroscopy (UV-vis), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDX). The XRD result confirmed the presence of a monoclinic CuO (Tenorite), and a hexagonal ZnO (Zincite) nanoparticles phase, which were both confirmed in the CuO–ZnO composite. The electron microscopy of the CuO–ZnO, CuO, and ZnO NPs showed a mixture of nano-scale sizes and spherical/short-rod morphologies, with some agglomeration. In the constituent’s analysis (EDX), no unwanted peak was found, which showed the absence of impurities. Antioxidant properties of the nanoparticles was studied, which confirmed that CuO–ZnO nanocomposite exhibited better scavenging potential than the individual metal oxide nanoparticles (CuO, and ZnO), and ascorbic acid with respect to their minimum inhibitory concentration (IC50) values. Similarly, the in vitro anticancer studies using MCF7 breast cancer cell lines indicated a concentration-dependent profile with the CuO–ZnO nanocomposite having the best activity over the respective metal oxides, but slightly lower than the standard 5-Fluorouracil drug.

Self-Assembled Interwoven Nanohierarchitectures of NaNbO3 and NaNb1–xTaxO3 (0.05 ≤ x ≤ 0.20): Synthesis, Structural Characterization, Photocatalytic Applications, and Dielectric Properties

Dependence on fossil fuels for energy purposes leads to the global energy crises due to the nonrenewable nature and high CO2 production for environmental pollution. Therefore, new ways of nanocatalysis for environmental remediation and sustainable energy resources are being explored. Herein, we report a facile surfactant free, low temperature, and environmentally benign hydrothermal route for development of pure and (5, 10, 15, and 20 mol %) Ta-doped horizontally and vertically interwoven NaNbO3 nanohierarchitecture photocatalysts. To the best of our knowledge, such a type of hierarchical structure of NaNbO3 has never been reported before, and changes in the microstructure of these nanoarchitectures on Ta-doping has also been examined for the first time. As-synthesized nanostructures were characterized by different techniques including X-ray diffraction analysis, electron microscopic studies, X-ray photoelectron spectroscopic studies, etc. Ta-doping considerably affects the microstructure of the nanohierarchitectures of NaNbO3, which was analyzed by FESEM analysis. The UV–visible diffused reflectance spectroscopy study shows considerable change in the band gap of as-synthesized nanostructures and was found to be ranging from 2.8 to 3.5 eV in pure and different mole % Ta-doped NaNbO3. With an increase in dopant concentration, the surface area increases and was equal to 5.8, 6.8, 7.0, 9.2, and 9.7 m2/g for pure and 5, 10, 15, and 20 mol % Ta-doped NaNbO3, respectively. Photocatalytic activity toward the degradation of methylene blue dye and H2 evolution reaction shows the highest activity (89% dye removal and 21.4 mmol g–1 catalyst H2 evolution) for the 10 mol % NaNbO3 nanostructure which was attributed to a change in the conduction band maximum of the material. At 100 °C and 500 kHz, the dielectric constants of pure and 5, 10, 15, and 20 mol % Ta-doped NaNbO3 were found to be 111, 510, 491, 488, and 187, respectively. The current study provides the rational insight into the design of nanohierarchitectures and how microstructure affects different properties of the material upon doping.

Water treatment with CoZnAl-LDH and its mixed metal oxide

Abstract CoZnAl-layered double hydroxide (LDH) was synthesized by homogeneous co-precipitation. CoZnAl-Mixed Metal Oxide (MMO) was prepared by calcining the LDH. The samples' structure and morphology were studied by analytical techniques including X-ray diffraction, N2 adsorption-desorption isotherm, scanning electron microscopy and UV–visible spectroscopy. Acid orange 7 (AO7) adsorption by as-prepared samples was studied. CoZnAl-MMO showed 526.32 mg/g adsorption capacity, higher than that of CoZnAl-LDH, 243.9 mg/g. Kinetic studies confirmed the pseudo-second-order and pseudo-first-order AO7 adsorption kinetics of the LDH and MMO, respectively. AO7 adsorption onto both LDH and MMO fitted the Langmuir isotherm model well. Band gap calculation confirmed the ability of this nano-MMO to operate in the visible light region. It displayed synergetic adsorption-photocatalytic performance under visible light and the removal efficiency was about 97%.