Chemical Co-precipitation Method Research Articles

Design and characterization of superparamagnetic iron oxide nanoparticles of nintedanib for theranostic application

This research was designed to develop and characterize citric acid-coated superparamagnetic nanoparticles (CA-SPIONs) and nintedanib esylate (NE) loaded CA-SPIONs (NE-CA-SPIONs) for their ability as cancer theranostics. The synthesis of SPIONs involved a chemical co-precipitation method. The XPS analysis confirmed the development of iron oxide (Fe3O4) nanoparticles by the presence of photoelectron lines ascribed to C 1 s, O 1 s, and Fe 2p. The CA-SPIONs and NE-CA-SPIONs had particle size of 21.30±2.3 nm and 30.65±3.2 nm, respectively. The zeta potential was found to be −42.7±1.8 mV for CA-SPIONs and −32.3±2.4 mV for NE-CA-SPIONs. The magnetic properties of CA-SPIONs and NE-CA-SPIONs was found to be 65.64 emu/g and 22.09 emu/g, respectively. The particles were spherical-shape and selective area electron diffraction pattern exhibited semi-crystalline nature of NE-CA-SPIONs. The NE-CA-SPIONs showed drug release of 98.85±3.7 % in 29 h. In vitro hemolysis assay demonstrated hemocompatibility of CA-SPIONs and NE-CA-SPIONs. The NE-CA-SPIONs were more cytotoxic compared to free NE across the A549 cells. The CA-SPIONs were proven to be safe with less percentage cell inhibition even at high concentration. The X-ray imaging of CA-SPIONs displayed their use as a contrast agent in diagnosis. Overall, the research suggested the use of CA-SPIONs and NE-CA-SPIONs in diagnosis and cancer treatment.

Fabrication of ternary zinc-nickel-copper oxide microsphere nanocomposite photoanode material for boosting dye-sensitized solar cell efficiency

The present study focuses on the development of cost-effective and efficient energy conversion material for fossil-fuel free society. In this context, ternary ZnO-NiO-CuO nanocomposite (NC) prepared using a facile chemical co-precipitation method was used as a photoanode material in dye-sensitized solar cell (DSSC). Concurrently, ZnO nanoparticles (NPs), binary ZnO-NiO and ZnO-CuO NCs were also prepared, characterized and employed as photoanode materials in DSSC. XRD diffraction analysis disclosed successful formation of nanomaterials with relevant structural parameters. SEM investigation displayed spherical and microsphere morphology of ternary ZnO-NiO-CuO NC. EDAX examination confirmed its purity. TEM and HRTEM analysis revealed that the morphology of ternary ZnO-NiO-CuO NC exhibits microspheres with porous nature, whose size ranges from 150 nm to 400 nm. Less intense PL peaks suggested anticipation of relatively low charge recombination, better charge separation and fast electron transport in ternary ZnO-NiO-CuO NC photoanode based DSSC. Consequently, photovoltaic behavior of DSSC integrated with ternary ZnO-NiO-CuO NC photoanode exhibited significantly higher PCE (η) of 4.96 % when compared to DSSC fabricated using pristine ZnO NPs (2.48 %), ZnO-NiO (3.18 %) and ZnO-CuO NC (4.35 %) photoanodes.

Facile fabrication of MgAl2O4/MWCNT nanocomposite for efficient and stable solar-driven degradation of organic dye

This work reports the synthesis and characterization of Magnesium Aluminate (MgAl2O4) and Magnesium Aluminate/Multi Walled Carbon Nanotube (MgAl2O4/MWCNT) nanocomposite by facile chemical co-precipitation method for the dye degradation application. MgAl2O4 and MgAl2O4/MWCNT nanocomposite are characterized by Scanning Electron Microscopy (SEM), x-ray Diffractometry (XRD), Raman Spectrometry, UV–vis Spectrophotometry (UV–vis), Fourier Transform Infrared Spectroscopy(FTIR), and x-ray Photoelectron Spectroscopy (XPS). Surface morphology of MgAl2O4/MWCNT nanocomposite exhibits entangled needle-like structures while MgAl2O4 spinel comprises agglomerated nanoparticles of different sizes. XRD confirms the formation of MgAl2O4. XPS identifies the chemical states and binding energies of constituent elements present in the sample. Optical properties reveal that addition of MWCNTs in MgAl2O4 decreases the optical bandgap energy from 3.02 eV to 2.78 eV. MgAl2O4/MWCNT nanocomposite shows reduced bandgap compared to pristine MgAl2O4 due to increased chemical defects or vacancies in intergranular regions and chemical interaction between MgAl2O4 and MWCNT, leading to the formation of new energy levels in MgAl2O4/MWCNT nanocomposite. Addition of MWCNTs provides a large surface area, more active sites, and enhances electron mobility between energy levels. MgAl2O4/MWCNT nanocomposite proves itself a better photocatalyst due to the fast degradation of Methyl Blue (MB) in 65 min as compared to MgAl2O4 which degrades the dye in 90 min. MgAl2O4/MWCNT nanocomposite also shows good stability and reusability even after performing the six cycles of dye degradation.

Effect of La2Sn2O7 content on the anti-arc erosion capability of Ag-Ni-La2Sn2O7 composites

La2Sn2O7 has high melting point and excellent thermal stability, which improves the wettability between matrix and reinforcement. In this study, La2Sn2O7 powder was synthesized by chemical coprecipitation method, and Ag-Ni-La2Sn2O7 composites were prepared by vacuum hot-pressing sintering. The effect of La2Sn2O7 content on the arc erosion behavior of Ag-Ni-La2Sn2O7 composites was studied. The Ag-Ni-La2Sn2O7 (85:12:3) composite has the lowest arc energy and the highest breakdown strength. With the increase of La2Sn2O7 content, the defects on the cathode surface decrease and the erosion areas become flat. After arc erosion, the samples generate Ag2O, NiO, La2O3 and SnO2. In this study, the mechanism of La2Sn2O7 to improve the anti-arc erosion capability of composites is mainly enhancing the viscosity of the molten pool by the ``pinning'' action, consuming energy by the decomposition of La2Sn2O7, and the promotion of arc movement.

Green and chemical syntheses of silver nanoparticles: Comparative and comprehensive study on characterization, therapeutic potential, and cytotoxicity

The emergence of metallic nanoparticles through green synthesis has garnered significant recognition, shaping global research efforts towards eco-friendly practices, often termed as the green revolution. Specifically, the green synthesis of silver nanoparticles (AgNPs) has made considerable strides in the past decade, becoming a prominent fixture in the realm of science and technology. The study explores the synthesis and characterization of silver nanoparticles (AgNPs) using Cassia fistula L. flowers extract through chemical co-precipitation (CM_AgNPs) and green methods (CFF_AgNPs). Characterization techniques, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), attenuated total reflectance fourier-transform infrared (FTIR), and X-ray diffraction (XRD), revealed irregular morphologies with agglomeration, polycrystalline nature, and intrinsic functional groups involved in capping AgNPs. Antioxidant assessment demonstrated superior antioxidative activity (84.48 %) in green-synthesized nanoparticles compared to chemically synthesized ones (75.87 %), and they exhibited dose-dependent anti-inflammatory effects with IC50 values CFF_AgNPs_30.19 μg/mL and CM_AgNPs _34.14 μg/mL respectively. The lower IC50 value of CFF_AgNPs_30.19 μg/mL signifies finer and better activity due to the presence of phytochemicals present in it. Whereas for CM_AgNPs the IC50 value is a 34.14 μg/mL which is solely due to AgNPs. To ensure the promising therapeutic aspects of AgNPs with a careful assessment of their safety profile, cytotoxicity of AgNPs on HEP3B cancer cells was evaluated through MTT assay, lactate dehydrogenase (LDH) release, and reactive oxygen species (ROS) level measurement. In the in vitro cytotoxicity evaluation, HEP3B demonstrated more pronounced dose-dependent adverse effects upon exposure to CFF_AgNPs compared to CM_AgNPs. This study underscores the bioactive potential of Cassia fistula L. mediated AgNPs, suggesting promising applications in biomedicine with environmental sustainability. The findings contribute to the growing interest in green synthesis methods for metallic nanoparticles and their potential benefits in various fields.

Influence of phase transition with annealing temperature on structural, morphological, and supercapacitive characteristics of molybdenum oxide nanostructures

In this study, molybdenum oxide nanostructures (MoO3 NSs) were effectively synthesized through a simple, low-cost, surfactant-free, low-temperature, and scalable chemical co-precipitation method and investigated their synergistic effect with annealing temperature on energy storage applications for the first time. Herein, we have reported a phase transition of MoO3 NSs from hexagonal to orthorhombic after the annealing temperature varied from 100°C to 500°C at constant time. Additionally, the resultant NSs were thoroughly examined for their physio-chemical characteristics, which revealed the stable phase formation of the MoO3 NSs, respectively. Furthermore, the electroactive MoO3 NSs were pasted on Ni-foam substrate (M@NF), and electrochemical properties were evaluated using a three-electrode setup at room-air temperature in 1 M KOH aqueous electrolyte across the potential range of 0 V to 0.786 V. As a result, the M@NF-5 electrode exhibited an impressive specific capacitance of 976.84 F g−1 at a scan rate of 1 mV s−1, a higher energy density of 73.69 Wh kg−1, and a power density of 655 W kg−1 at 5 mA g−1. The non-linear galvanostatic charge-discharge (GCD) profile aligns well with the cyclic voltammetry (CV) analysis. Both CV and GCD techniques confirm the pseudocapacitive behavior, with 83% capacitive retention observed after 2000 cycles. The fabricated symmetric device (M@NF-5//M@NF-5) exhibits enhanced electrochemical performance with a specific capacitance of 67.35 F g−1 at 5 mA g−1 and with an energy density of 18 Wh kg−1, and a power density of 1750 W kg−1 at a specific current. These findings underscore the potential of chemically deposited α-MoO3 as an auspicious material for use in supercapacitor applications.

Evaluation of structural parameters of monoclinic nanocrystalline CuO and study of sunlight-driven photocatalytic dye degradation, antimicrobial and antioxidant potential

Highly pure, crystalline and spherical-shaped Copper oxide nanoparticles (NPs) have been synthesized via facile chemical coprecipitation. Various models including the Scherrer, Monshi-Scherrer, Williamson-Hall, Size-Strain Plot and Halder-Wagner method have been applied to study the crystal structure characteristics. The lattice parameters associated with the monoclinic crystal lattice of CuO NPs were estimated to be a = 4.69 Å, b = 3.41 Å, c = 5.14 Å and β = 99.87(degree), unit cell volume V = 81.35Å3 and cell density dx = 6.49 g/cm3. The photocatalytic dye degradation proficiency at 20 mg/l CuO concentration and 120 min sunlight exposure results the order of percentage dye degradation Malachite Green (88.4%) > Crystal Violet (70.8%) > Eosin Yellow (70.2%) > Methylene Blue (54.08%) dyes. The antimicrobial activity assessment was done against the broad-spectrum pathogenic microbes unveiled the exceptional microbial controlling capability of CuO NPs. Furthermore, the antioxidant activity test demonstrated the potential free radical scavenging activity of CuO NPs with an IC50 value of 47.733 µg/ml. Highlights Synthesis of pure and spherical shaped nanocrystalline CuO was done by using low cost and facile chemical coprecipitation method. XRD, FTIR, FESEM, EDX, UV-Vis, and Raman spectroscopic techniques were used for characterization purpose. The structural and crystallographic parameters of monoclinic crystal structure of CuO NPs were evaluated successfully. The photocatalytic performance of CuO NPs follow the percentage dye degradation order as MG (88.4%) > CV (70.8%) > EY (70.20%) > MB (54.08%) after 120 minutes of sunlight exposure. CuO NPs exhibit promising antifungal activity against COVID-19 associated Pulmonary Aspergillosis (CAPA) causing pathogenic fung. CuO NPs show potential DPPH free radical scavenging activity with an IC50 value of 47.733 µg/ml.

Synthesis Of Nano-Porous Strontium Titanate Materials for Photocatalysis

Strontium titanate semiconductor materials have been widely used in the field of photocatalysis due to their high dielectric constant and band gap. Uniform, micron-sized SrTiO3 particles didn’t tend to aggregate, and the low surface area of larger particles could be improved by incorporating porous structures, thus offering superior performance for a range of applications. In this study, six mainly methods to prepare nano-porous SrTiO3 particles were showed and discussed. The methods include hydrothermal method，sol gel method, chemical co-precipitation method, high temperature solid phase method, hard template method and soft template method. These processes and their advantages and disadvantages were analysised.

Synthesis, characterization and magnetic properties of iron oxide nanoparticles from reverse chemical co-precipitation method

Studying magnetic characteristics of iron oxide nanoparticles was highlighted as a key step in creating potential powder nanomaterials. The occurrence of electron spins parallel to the crystallographic orientations and single domain nanopartilces are the recognized causes of superparamagnetism in bulk magnetite. Nanoparticles whose size could be tuned exhibit this superparamagnetism effect. The reverse co-precipitation process is used to create the current magnetite nanoparticles. The iron oxide nanoparticles were synthesized by reverse chemical coprecipitation method and were confirmed based on XRD data. The room temperature magnetic property was studied and the tiny levels of coercivity and remanence indicate that the samples may exhibit superparamagnetic nature.

Determination of the possibility of the synthesis of Zn-Al layered double hydroxides, intercalated with peroxyanions, as a perspective solid disinfectant

Infectious diseases in the modern world pose a significant threat to humanity in the form of epidemics and pandemics. To prevent and combat them, it is necessary to carry out antiseptic and disinfectant treatments of various environments, household and industrial surfaces, as well as wounds of various origins. Double-layer hydroxides intercalated with peroxyanions as active oxygen compounds are promising materials for this. In order to determine the possibility of obtaining Zn-Al double-layer hydroxide intercalated with peroxylactic acid anions, samples were synthesized by the method of chemical co-precipitation in the presence of peroxylactic acid at controlled pH (8, 10) and t=20 ℃. The properties of the synthesized samples were investigated. The content of active oxygen (in terms of H2O2) was determined by the method of iodometric titration with the calculation of the percentage of hydrogen peroxide that was intercalated in double layered hydroxides, remained in the mother solution or was lost. The crystal structure was studied by X-ray phase analysis, the yield of samples was determined gravimetrically, and sedimentation was determined by measuring and normalizing the thickness of the sediment layer. It was found that the samples synthesized at pH=8 and 10 are biphasic and consist of an oxide phase and a double-layer hydroxide phase. The determined content of active oxygen (in terms of H2O2) in the samples synthesized at pH=8 (0.533 %) and at pH=10 (0.876 %) confirms the success of the synthesis of Zn-Al-peroxylactate double layered hydroxides. Synthesis at elevated pH is promising. A low percentage of H2O2 intercalation was revealed – 4.03–6.54 %, the majority of hydrogen peroxide (82.36-94.44 %) remains in the mother solution. The yield of the synthesized samples was determined to be 61.9 % and 79.5 % at synthesis pH of 10 and 8, respectively. The sedimentation properties of the samples were studied and their improvement was shown when the pH of the synthesis was increased

Enhanced dye-sensitized solar cell performance and electrochemical capacitive behavior of bi-functional ZnO/NiO/Co3O4 ternary nanocomposite prepared by chemical co-precipitation method

Increasing prerequisites for sustainable energy storage and conversion technologies have necessitated the exploration of advanced materials with improved properties. Here, we present the synthesis and characterization of ZnO nanoparticles (NPs), ZnO/NiO, ZnO/Co3O4 and ZnO/NiO/Co3O4 NCs as promising bi-functional materials for dye-sensitized solar cell (DSSC) and electrochemical energy storage applications. A facile chemical co-precipitation approach was followed to synthesize pure ZnO NPs, ZnO/NiO, ZnO/Co3O4 and ZnO/NiO/Co3O4 NCs. The structural and morphological analyses revealed the successful integration of ZnO, NiO, and Co3O4 NPs and also the formation of well-defined core-shell and homogenous nanocomposite structures. The XRD and HRTEM analyses confirmed the crystalline nature and nanoscale morphology of synthesized materials, respectively. The photovoltaic performance of DSSC fabricated using ternary ZnO/NiO/Co3O4 NC photoanode showed optimum dye-loading and best solar to electrical energy conversion efficiency with Jsc of 11.29 mA cm−2 and ƞ of 4.66%, which was considerably higher than the DSSC fabricated using pure ZnO NPs photoanode (ƞ = 2.01%). The increment in photocurrent density (Jsc) could be ascribed to the perfect band alignment of NiO and Co3O4 NPs in the ternary NC. Further, the ZnO/NiO/Co3O4 NC photoanode integrated DSSC disclosed 97% retainment in energy conversion efficiency even after 10 days of operation. The electrochemical performance of supercapacitor fabricated using ternary ZnO/NiO/Co3O4 NC showed high specific capacitance of 534.7 Fg−1 at 1 Ag−1 with favourable rate ability (∼52% at 16 Ag−1), good cyclic stability (91.07%) and low internal resistance. Moreover, the ZnO/NiO/Co3O4 NC at a current density of 2 Ag−1 exhibited a significantly high capacitance value of 463.1 Fg−1, which was 1.93, 1.58 and 1.22 times greater than ZnO NPs, ZnO/Co3O4 NC and ZnO/NiO NC, respectively.

Field-induced magnetorheological study towards the active magneto-viscoelastic behavior of stable MnFe2O4 magnetic nanofluid

This work presents the fine-tuned synthesis of MnFe2O4 oleic acid-coated magnetic nanoparticles (MNPs) by the chemical co-precipitation method. The X-ray photoelectron spectroscopy (XPS) was utilized to investigate the elemental composition and oxidation state of oleic acid-coated MnFe2O4 MNPs. The Fourier transform infrared spectroscopy (FTIR) spectra were used to confirm the functional groups in the oleic acid-coated MnFe2O4 magnetic nanoparticles. The spherical shape of MnFe2O4 MNPs is confirmed by Field emission scanning electron microscopy (FESEM) and High-resolution transmission electron microscopy (HRTEM) techniques. Zeta potential (ζ) measurements were performed to confirm the stability of MnFe2O4 magnetic nanofluid (MNF). Magnetic measurements (M−vs−H) reveal the saturation magnetization, Ms = 20.3 emu/g and coercivity, HC = 30 Oe, confirming the single domain superparamagnetic nature at 300 K. Field-induced shear thinning behavior of the MnFe2O4 magnetic fluid is confirmed by a power law, η = c γn + n∞ and steady-state behavior measurements. Magneto viscous effect initially increased at a low shear rate of 20 s−1 and then decreased at a higher shear rate of 100 s−1, which confirms the stability of the MnFe2O4 magnetic fluid. Also, the highest deflection angle, θ = 243 m.rad of MnFe2O4 magnetic fluid was observed at a moderate shear rate 100 s−1 and a high magnetic field of 1.2 T, while the lowest value of deflection angle, θ = 65 m.rad was observed in the absence of magnetic field. In contrast, the storage modulus (G') is greater than the loss modulus (G''), in corroboration with the viscoelastic-to-viscous behavior of MnFe2O4 magnetic fluid.

Structure and morphology modification of ZnO nanocrystals via substitutional cobalt doping for enhanced electrochemical activity

This study investigated the electrochemical performance of the morphologically and structurally modified Co-doped ZnO nanocrystals synthesized via the chemical co-precipitation method. The structural properties were characterized by XRD, where the lattice parameters and volume got smaller with the increasing amount of Cobalt doping. The compositional analyses showed that 1.5 and 2.5 at% of Cobalt was present in the Co-doped ZnO nanocrystals. The FT-IR analyses showed that Zn–O (tetrahedral) and Zn–O (octahedral) vibrational modes are present for the precipitated ZnO-based nanocrystals. Besides that, the characteristic Raman spectra mode for ZnO displayed redshift, and more modes were activated, which showed a change in the defect chemistry after the cobalt substitution into the ZnO host lattice. A significant change was observed in morphology where the pristine ZnO formed nanoflower composed of nanoflakes and the Co-doped ZnO nanoparticles formed nanospheres. Lastly, cyclic voltammetry was performed at different scan rates where typical Faradaic peaks were observed for all the samples, and the electrochemical performance was increased with the small amount of Co doping into the ZnO lattice. The samples showed improved pseudocapacitive behavior, suggesting that Cobalt doped ZnO nanoparticles synthesized via the chemical co-precipitation method can be a potential electrode material for pseudocapacitor applications.

Comparison of the lithium storage performance and electrochromic behavior of Prussian blue and its analogues

Nanosized Prussian blue (FeHCF), cobalt hexacyanoferrate (CoHCF), nickel hexacyanoferrate (NiHCF), copper hexacyanoferrate (CuHCF), and zinc hexacyanoferrate (ZnHCF) particles are prepared by facile chemical co-precipitation method. The microstructure of the samples is characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and N2adsorption measurements. The lithium storage behavior and electrochromic performance of the five samples are systematically studied and compared. Among them, FeHCF presents two pairs of distinct charge/discharge plateaus; the other four samples exhibit one pair of charge/discharge plateaus, and plateau potential varies with the change of metal centers. During discharge and charge processes, the color of FeHCF can be reversibly switched in three colors (blue ↔ white ↔ green); while the CoHCF, NiHCF, CuHCF, and ZnHCF can be reversibly switched in two different colors corresponding to green ↔ red, yellow ↔ colorless, yellow brown ↔ dark red, and light yellow ↔ colorless, respectively. The results reported in this work could be helpful for rational design and performance regulation of Prussian blue analogues as electrochemical energy storage and electrochromic bifunctional materials.

Defects assisted the enhancement of optical and ferromagnetism in Zn1-xCoxS quantum dots: Toward efficient optoelectronic and spintronic applications

Colloidal Co-doped ZnS Quantum dots (QDs) were successfully synthesized through a facile and effective chemical co-precipitation method using polyethylene glycol (PEG) as a capping agent. A comprehensive study on the structure, optoelectronic, and magnetic properties of ZnS: Co2+ QDs was thoroughly carried out using diverse characterization techniques. Transmission electron micrographs reveal spherical QDs with a mean particle size of 5 ± 0.5 nm, whereas the X-ray diffraction (XRD) analysis and Raman spectroscopy confirm the exclusive presence of cubic ZnS phase structure, without any signs of Co-related impurity phases. Energy-dispersive x-ray (EDX) analysis verifies the presence of only three elements: Zinc, Cobalt, and Sulphur, with nearly stoichiometric proportions. X-ray photoemission (XPS) analysis confirmed the presence of Co2+ ions in the divalent oxidation state as well as the fair existence of sulphur vacancies. Optical measurements demonstrate that Co-doping in ZnS leads to a decrease in the optical band gap owing to the presence of defects that create localized states within the band structure. In addition, the refractive index (n) is found to increase with Co-doping level due to the increase in the polarizability. The outcomes of optical properties reveal that the tunability of the optical band gap and dispersive oscillator parameters in Co-doped ZnS QDs results in an enhancement of the non-linear optical parameters, such as third-order non-linear optical susceptibility χ(3), and non-linear refractive index n2, rendering them well-suited for applications in optoelectronic devices. Furthermore, the room-temperature photoluminescence (PL) spectra revealed that the Co-doped ZnS QDs have two broad emission bands, including the blue emission, and the green emission. By varying the level of Co-doping, it becomes possible to effectively control the relative PL intensities of dual-color emissions, highlighting their potential for producing adjustable color outputs. The room temperature ferromagnetic behaviour of the QDs has been observed and analyzed in accordance with the bound magnetic polarons model. These findings suggest that Co-doped ZnS QDs can be utilized effectively in the design of spintronic devices.

Evolution of Ni-induced orthorhombic phase in SnO2: Influence of Ni on the optical and photocatalytic properties

This paper presents the impact of nickel doping on the structural, optical and photocatalytic characteristics of Sn1-xNixO2 (x = 0, 0.3, 0.05, 0.07) nanoparticles. The samples are synthesized via the chemical co-precipitation method. Information on the structural properties of the samples is obtained via the Rietveld refinement technique. As the dopant concentration increases, a partially stable orthorhombic phase emerges and becomes prominent, indicating a correlation with the amount of Ni dopant. This orthorhombic phase arises during the transformation from the amorphous state to a more stable crystalline phase. The FESEM-EDAX analysis demonstrates the uniform distribution of agglomerated particles. Additionally, the Raman data provides information related to surface defects and vacancies. A minor increase in the band gap value is detected, and this observed blue shift can be attributed to the Burstein-Moss effect. The samples exhibit a strong blue emission, primarily attributed to surface defects and states, particularly due to the oxygen vacancies. The CIE coordinates show an increase in blue colour purity, making the samples suitable for blue components in white-light emitting diodes. However, the photocatalytic study reveals only partial degradation of methylene blue under visible light conditions.

Synthesis of nickel-copper layered double hydroxides for asymmetric supercapacitors by low-temperature chemical co-precipitation method

Synthesis of nickel-copper layered double hydroxides for asymmetric supercapacitors by low-temperature chemical co-precipitation method

In English

Currently, textile and food industries produce a significant volume of sewages containing azo dyes and other organic pollutants. These effluents are serious environmental threats, so new methods for their treatment and the degradation of azo dyes are attracting much attention. Composite materials based on TiO2 modified by noble metals and nanoceria show high activity in the photodegradation of organic contaminates and are proposed for hydrogen synthesis as well. To optimize the treatment of contaminants, different processes can combine including the strategies of adsorption, photoluminescence, photocatalysis, etc. The synthesized TiO2-based nanomaterials (sols, powders) will be exploited for bioremediation due to their small size and surface plasmon resonance from noble metals. Binary nanocomposites based on TiO2 were obtained by the chemical co-precipitation method from solutions of titanium tetraisopropoxide (TTIP) and inorganic salts of cerium, silver, and palladium. It has been stated that TiO2 is represented by anatase with primary particle size (CSR) from 8.5 to 16.8 nm, depending on the nature and concentration of the dopant. It is shown that Ag is reduced on the surface of anatase particles and blocks their growth, while Pd and Ce penetrate the titanium dioxide matrix in the form of small clusters with the deformation of the anatase crystal lattice. Nanocomposite particles formed loose and fragile aggregates, which spontaneously dispersed in solutions of dyes with the formation of colloid-stable sols, required the use of a centrifugal field for their sedimentation. Nanoparticles of TiO2&Pd were electronegative and others were electropositive according to the values 4.1÷9.6 of ZPC (zero point of charge). It was shown that the particles of all composites sorbed Methylene Blue (MB) without photocatalytic activity under the visible light to any dye. Moreover, anionic dyes such as Orange-G (Or-G) and Methyl Orange (MO) were excellently discolorated in the presence of TiO2&Pd system; cationic dyes of MB and Rhodamine B (RhB) discolorated too with the TiO2, TiO2&CeO2, and TiO2&Ag systems under UV light action. As such, photocatalysis tests showed that Orange-G’s and MO’s discoloration was higher for TiO2&Pd (2 wt. %) and TiO2 systems with the correlation coefficient R2 0.999.

Microwave-assisted synthesis, characterization, and oxytetracycline antibiotic sorption performance of a novel magnetic nanohybrid material: MnFe2O4@black cumin solid waste-derived activated carbon

Using waste resources to synthesize functional materials without polluting the environment is important for sustainable life and development. In the present study, a novel magnetically separable activated carbon nanohybrid (MnFe2O4@BAC) was produced by using the microwave-assisted chemical co-precipitation method of industrially processed black cumin solid waste-derived activated carbon (BAC) and manganese ferrite nanoparticles (MnFe2O4). It was characterized by VSM, XRD, Raman, BET, SEM-EDX, FTIR, Boehm titration, and pHPZC analysis techniques. Spinel MnFe2O4 nanoparticles significantly affected the pore properties of BAC. MnFe2O4@BAC exhibited a saturation magnetization property of 14.6 emu/g. Also, the optimal sorption conditions of oxytetracycline (OTC), which was chosen as a model to test the antibiotic sorption ability from water, were decided according to the optimum influences of operational variables. The kinetic and isotherm results best described the pseudo-second-order and Langmuir models, respectively. The maximum OTC sorption ability of MnFe2O4@BAC was determined as 591.7 mg/g under specified optimal sorption conditions. Thermodynamic parameters were calculated to show that the sorption is spontaneous volitional and endothermic. The spent MnFe2O4@BAC was accumulated after sorption using an external magnetic field for subsequent reuse and showed excellent reusability stability.

Synthesis and high-temperature phase transformation behavior of Dy2O3–Sc2O3 co-stabilized ZrO2 powders prepared by cocurrent chemical coprecipitation

In this study, Dy2O3–Sc2O3 co-stabilized ZrO2 (DyScSZ) powders with various stabilizer ratios were synthesized by cocurrent chemical coprecipitation method. The difference analysis of phase composition and microstructure was conducted on the synthesized powders in detail. The phase evolution and phase transformation behaviors of the synthesized powders were also investigated. Results show that all of the powders were synthesized with nanoscale and exhibit subglobose morphology. The excessive elevation of Sc2O3 fraction in total stabilizers was adverse to the formation of the synthesized powders with pure tetragonal phase, which also exhibit a significant effect both on the phase transformation behaviors and the final volume fractions of transform products. The 2.5Dy1.0ScSZ powders exhibit favorable phase stability resulting from the nano-size effect and the synergies of Dy2O3 and Sc2O3 stabilizers during the phase transformation process. Moreover, a phase transformation mechanism of DyScSZ was proposed based on the new phase nucleation and growth theory.