Simple Co-precipitation Process Research Articles

Impact of Carbon Dots on the Structural, Morphological, Magnetic, and Electrochemical Performance of Zn Ferrite for Energy Storage Applications

Magnetic core-shell Zn ferrite and carbon dots (C-dots) composite have been synthesized in this work using a simple coprecipitation and hydrothermal process, respectively. X-ray diffraction (XRD) patterns demonstrate an inverse spinel structure of Zn ferrites; the lattice parameter has decreased from 8.19Å to 8.10Å with C-dots. Scanning electron microscopy (SEM) images reveal rods-like structures for C-dots, and in the composite case, it is uniformly dispersed using low contrast consecutive C-dot layers to produce a core-shell structure. Zn ferrites are non-uniform in size, whereas C-dots and their composites are in uniform shape according to SEM images. The energy dispersive X-ray (EDX) study indicates that the substitution has been successful. For Zn ferrites, and composite, the Fourier transform infrared (FTIR) spectra shows that the absorption band of the tetrahedral site at 990 cm-1, and 870 cm-1, respectively. Different bonds in the infrared spectrum match specific function groups and bonding in various chemicals. The vibrating sample magnetometry (VSM) results indicates that the composite displays ferrimagnetic behavior. The specific capacity for composite has been found to be 2351 and 1790 F/g using cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) measurements, respectively. Higher electrochemical performance of the prepared composites may be helpful for energy storage systems.

Bimetallic two-dimensional metal-organic frameworks nanosheets derived bimetallic@C composite materials for effective electromagnetic wave absorption

The development of information technology has resulted in serious environmental pollution and health concerns due to electromagnetic wave radiation. There is a necessity to develop electromagnetic wave absorbers with strong absorption, wide bandwidth, thin thickness, light weight, and environmental friendliness. In this study, a series of Ni4Cux@C composite materials was synthesized through a simple coprecipitation and pyrolysis process. The morphology and absorption properties of the composite materials were precisely tuned by adjusting the ratio of the bimetallic Ni and Cu. The Ni4Cux@C two-dimensional nanosheets were designed to possess a high specific surface area and abundant porous structure, thus optimizing impedance matching. Its strong dielectric loss capability is collectively contributed to the excellent graphitization degree and multiple polarizations. Additionally, the dispersion of NiCu alloy nanodisks within the carbon matrix leads to the aggregation of a large number of free space charges at the heterogeneous interface, inducing the formation of interfacial polarization. The well-designed Ni4Cu2@C composite materials exhibit outstanding electromagnetic wave absorption capabilities, with the optimal reflection loss reaching -74.9 dB, and the maximum effective absorption bandwidth reaching 6.8 GHz (2.9 mm). This work provides an important research foundation for the rational design of a new generation of two-dimensional bimetallic electromagnetic waveabsorption materials.

Eco-synthesis route: Developing bis-hydrazono[1,2,4]-thiadiazoles via a green synthetic approach with calcium oxide-chitosan nanocomposite

Modern environmental organic chemistry is focused on developing cost-efficient, versatile, environmentally acceptable catalytic chemicals that are also highly effective. Herein, hybrid calcium-chitosan nanocomposite films was prepared by doping calcium oxide molecules into a chitosan matrix at weight percentage (15, 20, and 25 % wt. chitosan‑calcium) using an easy and affordable simple co-precipitation process. The CS–CaO nanocomposite's structure was elucidated using analytical techniques such as Fourier transform infrared (FTIR), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). Based on the X ray diffraction (XRD) measurements, the crystallinity was reduced by the incorporation of the CaO molecules. Also, from the calculation of the Debye-Scherrer equation on this X-ray diffraction (XRD) pattern, the crystallite size was found to be 17.2 nm for the nanocomposite film with 20 % wt. The energy dispersive spectroscopy graph demonstrated the presence of the distinctive Ca element signals within the chitosan, with the amount in a sample of 20 % wt. being discovered to be 21.32 % wt. For the synthesis of bis-hydrazono[1,2,4]thiadiazoles, the obtained CS–CaO nanocomposite could be employed as a potent heterogeneous recyclable catalyst. Better reaction yields, quicker reactions, softer reaction conditions, and green reusable efficient biocatalysts for several uses are just a few advantages of this approach.

Superparamagnetic iron oxide nanoparticles functionalized by biocompatible ligands with enhanced high specific absorption rate for magnetic hyperthermia

This study introduces a novel green nanocomposite system of iron oxide coated with secondary metabolites (Fe3O4@SM) and compares it with commonly used materials for hyperthermia cancer treatment. Fe3O4@SM magnetic nanoparticles were synthesized through a simple co-precipitation process using metal precursors, followed by heating in pressure reactor to obtain superparamagnetic nanoparticles (Hc = 36.5–54.1 Oe at 300 K). These nanoparticles were subsequently coated with plant-based phytochemicals. XRD analysis confirmed the presence of magnetite iron oxide nanoparticles. SEM images further confirmed the spherical shape of the synthesized nanoparticles, exhibiting a face-centered cubic (FCC) iron oxide structure with sizes ranging from 12±7–85±15 nm. Characterization through dynamic light scattering (DLS) and zeta potential (ζ) analysis demonstrated colloidal stability, with a polydispersity index (PDI) ranging from 0.226 to 0.436 and zeta potential values ranging from −29.761–1.85 mV. The surface of the nanoparticles was analyzed using GC-MS, which identified bioactive functional groups including ester (42.79 %), terpene (20.69 %), hydrocarbons (17.4 %), and carboxylic (12.37 %) compounds. Compared to Fe3O4 and Fe3O4@GO, Fe3O4@SM exhibited a higher rate of temperature increase within the therapeutic range, reaching Tmax = 45°C with a heating rate (dT/dt) of 0.273 °C/s and specific absorption rate (SAR) of 230.6 W/g at 304 kHz and 400 Oe. In vitro assays utilizing a triple negative breast cancer microenvironment confirmed the non-toxicity of these materials through a DNS assay. The developed nanoparticles offer dual mechanisms of action, combining thermal and chemo effects, making them promising candidates for hyperthermia cancer treatment.

Eu2CuO4 nanostructures: A simple co-precipitation pathway, characterization, and promising photocatalytic application for dye removal under visible light

Contamination of water has become an international concern, and finding efficient and sustainable methods to eliminate harmful pollutants is crucial for ensuring that clean and safe water resources are available. A promising approach in this regard is photocatalysis, which uses light energy to initiate chemical reactions that break down organic contaminants into harmless byproducts. This study presents a nanophotocatalyst based on europium copper oxide (Eu2CuO4) for the elimination of hazardous pollutants. The fabrication of Eu2CuO4 nanostructures was achieved through a simple and rapid co-precipitation process. According to diffuse reflectance spectroscopy (DRS), Eu2CuO4 has an optical bandgap of 1.56 eV, making it suitable for use in visible light. A variety of techniques were used to characterize Eu2CuO4 nanostructures, including XRD, FESEM, FTIR, VSM, HRTEM, BET, EDS, and LC-MS. In order to maximize effectiveness, several variables were considered, such as the amount of Eu2CuO4 used, the concentration of toxic pollutants, and the pH of the solution. It was found that Eu2CuO4 was quite effective in degrading various organic pollutants, particularly methyl orange (MO) of water. Using 50 mg of Eu2CuO4 in the presence of 20 ppm MO and exposing it to visible radiation for 100 min resulted in 94.9 % of MO being destroyed. A further analysis revealed that hydroxyl radicals (•OH) and holes (h+) played a dominant role in pollutant photodegradation. In light of this finding, Eu2CuO4 may serve as a valuable candidate for developing new materials that are capable of successfully removing contaminants from water.

Multifunctional glucose-powered nanomotors with robust dual enzyme mimic activities

Catalytic micro-/nanomotors (MNMs) that use H2O2 as fuel to generate O2 bubbles for propulsion hold great promise for exciting applications in the biological and environmental fields. However, it is still a challenge to alleviate or avoid the negative impact of H2O2 on the ecological environment of water body. Herein, a novel glucose-driven nanomotor with robust dual enzyme-like activities was prepared by precisely controlling the phase composition and enzyme immobilization to construct a 3D hierarchical structure integrating Fe-MOF, MnO2 and glucose oxidase (GOx) on halloysite nanotube (HNTs) support. Embedding GOx into the framework of Fe-MOF by a simple one-step coprecipitation process allowed the in-situ generation of H2O2 in the presence of glucose. Such H2O2 could be further decomposed to O2 bubbles to drive nanomotors. Meanwhile, O2 bubbles and residual H2O2 could convert to active species superoxide radical (O2•−) and hydroxyl radical (•OH) due to the high peroxidase/oxidase-like activities of Fe-MOF/MnO2 in nanomotors. As a proof of concept, the as-synthesized nanomotors could realize sensitively colorimetric detection of glutathione (GSH) with a detection limit of 9.3 × 10−8 M. In particular, the nanomotors could also rapidly degrade tetracycline hydrochloride (TCH) under neutral conditions without additional H2O2. It is envisioned that the new strategy that combines strong enzyme-like activity with enhanced autonomous motion can promote the nanomotors efficiency for biomolecular sensing and environmental remediation.

Enhancement in photo sensing and photocatalytic degradation activity of Cu doped ZnO nanoparticles prepared by co-precipitation method

In the present work, Copper (Cu) doped zinc oxide (ZnO) nanoparticles were prepared using a simple and cost-effective co-precipitation process. The objectives of the proposed work are to identify the cause of Cu dopant on the crystalline structure, morphology, optical characteristics of ZnO nanoparticles for photocatalytic as well as photosensing applications. X-ray diffraction (XRD) and Field emission scanning electron microscope (FESEM) examinations were used to identify the crystal structure and morphology of the prepared samples. The crystallite size of the undoped ZnO sample was 44 nm, which gets reduced to 36 nm with 5% Cu-doping. Using diffuse reflectance spectroscopy (DRS), the band gap of prepared samples of undoped to 5 wt% Cu doped ZnO was calculated, and it was found to be reduced from 3.31 to 3.26 eV. Photoluminescence (PL) spectra show a decrease in luminous intensity which is in line with the photocatalytic behavior. 5 wt% Cu doped ZnO sample displayed maximum degradation efficiency of 85% in 75 min and degradation rate of 0.02 min−1. Additionally, photo-sensing studies of the 5 wt% Cu doped ZnO sample showed higher responsivity (R), detectivity (D*) and external quantum efficiency (EQE) values of 1.93 × 10−1 AW−1, 1.09 × 1011 Jones and 45% respectively. The rise and fall time of 5 wt% Cu doped ZnO photodetector is in the order of 0.3 and 0.5 s.

Design, synthesis and formation mechanism of a novel entropy-stabilized perovskite oxide derived from barium cerate/zirconate

Through the use of the cluster-plus-glue atom model, we theoretically designed a novel perovskite-structured oxide (ABO3), derived from a barium cerate/zirconate, with the following chemical formula: Ba(Ce0.2Zr0.2Gd0.2La0.2Y0.2)O2.7. Given the five different cations on the B-site, we demonstrated that the novel system is an Entropy-Stabilized Perovskite Oxide, which exhibits a reversible transition from a single-phase to a multiphase system. By using a simple coprecipitation process, we were able to synthesize and then sinter a well-densified single-phase perovskite. In the present work, we discussed for the first time the complex interactions occurring among the involved species that, depending on the treatment conditions, could lead to the formation of either an entropy-stabilized orthorhombic perovskite or a metastable cubic perovskite.

In vitro analysis of iron oxide (Fe3O4) nanoparticle mediated degradation of polycyclic aromatic hydrocarbons (PAHs) and their antimicrobial activity

To degrade anthracene, magnetite nanoparticles were produced using a simple co-precipitation process. The fabricated nanoparticles have been analyzed for structural and optical properties. XRD examination revealed that the produced Fe3O4 nanoparticles were cubic phase, having a mean crystallite dimension of 18.84 nm. DLS determined the hydrodynamic diameter of Fe3O4 nanoparticles to be 182 nm. UV–Vis research revealed that Fe3O4 nanoparticles absorb at 390 nm. A peak at 895 cm−1 in the FT-IR study indicated the metal-oxygen connection. The synthesized Fe3O4 nanoparticles demonstrated an effective photocatalytic performance towards anthracene degradation and was found to be 86.55%. Furthermore, Fe3O4 nanoparticles showed the highest antimicrobial activity against Bacillus subtilis was 19.43 mm. The present study is the first and foremost study determining the dual role of Fe3O4 nanoparticles towards bioremediation and biomedical applications.

Structure, morphology, composition, optical properties of CuO/NiO nanocomposite for electrochemical energy storage devices

A CuO/NiO nanocomposite synthesized using a simple co-precipitation process was employed to produce a high-performance electrochemical supercapacitor. The crystal nature, particle,composition, chemical state, and optical properties were investigated using powder XRD, TEM, EDX, FTIR, XPS, and UV–visible spectroscopy respectively. The electrochemical properties of CV, GCD and EIS are measured in 1 M NaOH. At a 0.5 Ag−1 current density, the CuO/NiO composites exhibit greater capacitance (290.56 Fg-1) when compared to the individual compounds of CuO (165.20 Fg−1) and NiO (190.34 Fg−1). After 2000 cycles the CuO/NiO electrode was excellent 90% of capacity retention. The Ragone plot discovers better energy density of 4.24Wh kg−1 and power density of 10.67 kW kg−1 were provided by the CuO/NiO nanocomposites. The maximal ionic conductivity for the CuO/NiO nanocomposite is 3.56 10-4 S/cm based on the Cole-Cole plot. Furthermore, galvanostatic charge–discharge (GCD), peak current, dielectric properties of dielectric constant and electric modulus are discussed in this work. These results have indicated that the CuO/NiO nanocomposite is an excellent material for supercapacitor electrode construction.

Textural properties and adsorption behavior of Zn–Mg–Al layered double hydroxide upon crystal violet dye removal as a low cost, effective, and recyclable adsorbent

The preparation of adsorbents plays a vital role in the adsorption method. In particular, many adsorbents with high specific surface areas and unique shapes are essential for the adsorption strategy. A Zn–Mg–Al/layer double hydroxide (LDH) was designed in this study using a simple co-precipitation process. Adsorbent based on Zn–Mg–Al/LDH was used to remove crystal violet (CV) from the wastewater. The impacts of the initial dye concentration, pH, and temperature on CV adsorption performance were systematically examined. The adsorbents were analyzed both before and after adsorption using FTIR, XRD, and SEM. The roughness parameters and surface morphologies of the produced LDH were estimated using 3D SEM images. Under the best conditions (dose of adsorbent = 0.07 g and pH = 9), the maximum adsorption capacity has been achieved. Adsorption kinetics studies revealed that the reaction that led to the adsorption of CV dye onto Zn–Mg–Al/LDH was a pseudo-second-order model. Additionally, intraparticle diffusion suggests that Zn–Mg–Al/LDH has a fast diffusion constant for CV molecules (0.251 mg/(g min1/2)). Furthermore, as predicted by the Langmuir model, the maximal Zn–Mg–Al/LDH adsorption capacity of CV was 64.80 mg/g. The CV dimensionless separation factor (RL) onto Zn–Mg–Al/LDH was 0.769, indicating that adsorption was favorable. The effect of temperature was performed at 25, 35, and 45 °C in order to establish the thermodynamic parameters ∆Ho, ∆So, and ∆Go. The computed values indicated exothermic and spontaneous adsorption processes. The study presented here might be used to develop new adsorbents with enhanced adsorption capabilities for the purpose of protecting the water environment.

Synergetic Catalytic and Photocatalytic Performances of Tin-Doped BiFeO3/Graphene Nanoplatelet Hybrids under Dark and Light Conditions.

Because of a rapidly growing need for water, it is essential to find new fast and reliable ways of water purification from organic pollutants. For removing organic azo dyes from water, various catalysts and photocatalysts have been designed to meet crucial water needs. In this study tin (Sn) doped bismuth ferrite (BFO) nanoparticles have been synthesized using the sol-gel technique. Further, BFSO/GNP nanohybrids were synthesized by mixing BFSO nanoparticles with graphene nanoplatelets (GNPs) via a simple and cost effective coprecipitation process. XRD and SEM showed that BFSO/GNP nanohybrids are well grown in crystal structure along with uniform and homogeneous morphology. XPS supported the elemental composition and interface bonding of both materials present inside the nanohybrids. DRS and catalytic activities showed that BFSO/GNP nanohybrids are both dark and light active species for performing dye degradation activities during water purification. The as-synthesized nanohybrids provided efficient dye removal from water even in the absence of light owing to the presence of defects and trap-state carriers (electrons) inside the graphene sheets. The optimized nanohybrid BFSO-15/GNP showed 100% dye removal in 60 min with 90% catalytic activity under dark. The recyclability test showed stable and repeatable performance of BFSO/GNP nanohybrids up to 10 cycles of catalytic activities.

Enhanced and rapid photocatalytic degradation of toxic dyes by cobalt oxide and modified cobalt oxide under solar light irradiation

A solar light driven photo degradation approach for methylene blue (MB, model molecule of the thiazine dyes class) and malachite green (MG, model molecule of the triphenylmethane category) abatement by Co3O4 and Cr-Co3O4 spinel nanoparticles is reported. The effect of chromium load (5, 10 and 15%) in Co3O4 particles, synthesized by a simple co-precipitation process, was properly studied. The structural and morphological characteristics, chemical composition and optical properties of the materials were investigated by X-ray diffraction (XRD), Transmission Electron Microscopy(TEM), Field Emission Scanning Electron Microscopy – Energy Dispersive Spectroscopy (FE-SEM-EDS), FT-IR spectroscopy, UV–Vis diffuse reflectance spectroscopy (DRS),photoluminescence (PL) and BET surface area analysis. It was observed that properly tuning the initial pH, the initial dye concentration, the agitation time, and the photocatalyst dose, (10)Cr-Co3O4 exhibited an enhanced photocatalytic activity compared to that of pristine Co3O4, demonstrating the positive role of Cr doping In fact, the PL investigation showed that Cr doping in the Co3O4 lattice greatly increase the separation of electron-hole (e−/h+) pairs, whereas the UV DRS spectra and Tauc plot revealed a decrease in the band gap energy for Cr-Co3O4,. The investigations demonstrated that the MB dye degradation increases from 88% to 96% at pH = 11 after doping of Co3Oby 10% of Cr. Similarly, the Cr doping allowed to enhance the MG dye degradation from 85% to 92% at pH = 9. The photo degradation kinetics of both MB and MG dyes by Cr-Co3O4 and Co3O4 NPs were of pseudo-first-order mode. The active species involved in the photocatalytic process were properly identified using various scavengers by trapping holes and radicals. Finally, the photocatalysts showed good stability during recycling maintaining high performances after 5-time usage. .

Efficient and Rapid Removal of Pb(II) and Cu(II) Heavy Metals from Aqueous Solutions by MgO Nanorods

In this study, the adsorption capability of MgO nanorods for the quick and effective elimination of Cu(II) and Pb(II) heavy metals from wastewater was examined. The MgO nanorods were produced via simple coprecipitation process. Various characterization techniques were used to investigate the morphological and chemical properties of the as-prepared nanomaterial. Moreover, the influences of initial heavy-metal ion concentration, pH, and contact time were investigated to evaluate the removal efficiency of the nanomaterials. The adsorption process followed pseudo-second order and Langmuir adsorption isotherm models, according to kinetics and isotherm investigations, respectively. MgO nanoparticles exhibited a high adsorption capacity for Cu(II) (234.34 mg/g) and Pb(II) (221.26 mg/g). The existence of interfering ions in the aqueous solution leads to a decrease in the adsorption capacity. Surface complexation was determined as the key contributor to the adsorption of Cu(II) and Pb(II) heavy-metal ions onto MgO nanorods. Notably, regeneration experiments demonstrate the potential applicability of MgO nanorods for the elimination of Pb(II) and Cu(II) from aqueous solution.

CO2-Based Poly(propylene carbonate) Functionalized for Sustainable Nanocomposites by a Controllable Magnetic Field

To alleviate environmental problems caused by carbon emissions, the modified application of the CO2-based polymer has attracted extensive scientific and technological interest. In this study, a series of sustainable nanocomposites were fabricated by a magnetic field with controllable direction to achieve nanofiller orientation in the CO2-derived poly(propylene carbonate) (PPC) matrix, and magnetic graphene nanosheets (FG) with varying magnetization were synthesized through a simple coprecipitation process using graphene oxide and iron-containing salts. The resultant nanocomposites not only exhibited anisotropic mechanical properties but also presented anisotropic thermal conductivity (TC) and electromagnetic interference (EMI) shielding properties in different magnetic field directions. The nanocomposites with a parallel orientation showed further significant improvements compared with the vertically oriented nanocomposites in terms of the mechanical properties, in-plane TC, and EMI shielding performances at the same FG loading. This was possibly attributed to the more regular arrangement of the two-dimensional FG nanosheets in the horizontal magnetic field. In addition, these nanocomposites showed a rapid magnetic response when the magnets were in close proximity. This study on PPC/FG nanocomposites with a controllable orientation structure and magnetic response could provide new ideas for the development of applications of CO2-based PPC materials in the functional and intelligent material field.

Pretreatment of membrane dye wastewater by CoFe-LDH-activated peroxymonosulfate: Performance, degradation pathway, and mechanism

When a membrane is used to treat dye wastewater, dye molecules are continually concentrated at the membrane surface over time, resulting in a dramatic decrease in membrane flux. Aside from routine membrane cleaning, the pretreatment of dye wastewater to degrade organic pollutants into tiny molecules is a facile solution to the problem. In this study, the use of layered double hydroxide (LDH) to activate peroxymonosulfate (PMS) for efficient degradation of organic pollutant has been thoroughly investigated. We utilized a simple two-drop co-precipitation process to prepare CoFe-LDH. The transition metal components in CoFe-LDH effectively activate PMS to create oxidative free radicals, and the layered structure of LDH increases the number of active sites, and thereby considerably enhancing the reaction rate. It was found that the reaction process produced non-free and free radicals, including singlet oxygen (1O2), sulfate radicals (SO4•−), and hydroxyl radicals (•OH), with 1O2 being the dominant reactive species. Under the optimal conditions (pH 6.7, PMS dosage 0.2 g/L, catalyst loading 0.1 g/L), the degradation of Acid Red 27 dye in the CoFe-LDH/PMS system reached 96.7% within 15 min at an initial concentration of 200 mg/L. The CoFe-LDH/PMS system also exhibited strong resistance to inorganic ions and pH during the degradation of organic pollutants. This study presents a novel strategy for the synergistic treatment of dye wastewater with free and non-free radicals produced by LDH-activated PMS in a natural environment.

Efficient polyvinyl alcohol degradation via peroxymonosulfate activated by natural illite supported CoNi3O4 nanosheets

In this study, natural illite supported CoNi3O4 nanosheets (CN@I) were fabricated using a simple one-step coprecipitation process and tested for their ability to activate peroxymonosulfate (PMS) for polyvinyl alcohol (PVA) degradation. The probable activation mechanism of PMS by CN@I might be ascribed to the natural mineral carrier effect, numerous surface-bonded and structural hydroxyl groups, and efficient bonding with Co or Ni ions, according to density function theory (DFT) calculations. It is deduced from the results of electron paramagnetic resonance (EPR) and radical quenching tests that both the radical (•OH and SO4•-) and non-radical (1O2) pathways were engaged in the CN@I/PMS degradation of PVA. In addition, the possible degradation pathways of PVA were proposed based on the DFT calculation. The optimum operational conditions, impacts of ions and the reusability of catalyst during CN@I/PMS degradation of PVA degradation were further investigated. This work provides an interesting direction for the use of natural mineral-based catalysts to activate PMS for the treatment of PVA wastewater.

Oxidative adsorption of arsenic from water environment by activated carbon modified with cerium oxide/hydroxide

Arsenic contamination at high concentration frequently occurs in nature water environments and poses a great risk to human health. In this study, a cerium oxide/hydroxide-modified activated carbon was synthesized via a simple co-precipitation process as an adsorbent for the removal of arsenic from aqueous systems. Analysis of the cerium oxide/hydroxide-modified activated carbon by field emission scanning electron microscopy and X-ray photoelectron spectroscopy showed that cerium was mainly coated on the surface of activated carbon as cerium (IV) hydroxide. The arsenic adsorption performance of the adsorbent was investigated via batchwise adsorption and using a chromatographic system with a fixed bed column. Neutral pH conditions were optimal for removal of arsenic. Kinetic experiment data were described by a diffusion–chemisorption model. The adsorption isotherm followed the Langmuir model, and the maximum adsorption capacity of cerium oxide/hydroxide-modified activated carbon was 0.220 and 0.284 mmol g−1 for As(V) and As(III), respectively. Regeneration trials showed that cerium oxide/hydroxide-modified activated carbon could be regenerated with 0.1 mol L−1 NaOH solution as regenerant. During adsorption, redox reactions occurred in the aqueous and solid phases. As(III) was oxidized to As(V) by reduction of surface functional groups (CO, C-O, and cerium oxide/hydroxide) in the solid phase and by dissolved organic matters and surface functional groups in the aqueous phase. Chromatographic treatment with a fixed bed column of cerium oxide/hydroxide-modified activated carbon showed high arsenic adsorption efficiency. The repeated use of cerium oxide/hydroxide-modified activated carbon by chromatographic operation was also achieved.

Optimization studies for nickel oxide/tin oxide (NiO/Xg SnO2, X: 0.5, 1) based heterostructured composites to design high-performance supercapacitor electrode

This work describes component optimization studies for transition metal oxide composites (NiO/0.5 g SnO2 and NiO/1 g SnO2) synthesized using a simple co-precipitation process, as electrode materials for supercapacitor applications. XRD studies revealed the presence of cubic and tetragonal phases of crystals for NiO and SnO2, respectively. Crystallite sizes of NiO/0.5 g SnO2 and NiO/1 g SnO2 were determined from XRD data analysis, that were in range of ∼10–11 nm. Morphological analysis revealed the formation of in homogenuous particles of NiO/0.5 g SnO2 and NiO/1 g SnO2 with great degree of aggregation. As synthesized NiO/1 g SnO2 and NiO/0.5 g SnO2 showed the specific capacitance of 1035.71 Fg-1 and 980.76 Fg-1, respectively. Moreover, NiO/1 g SnO2 showed 64% capacitance retention at 5 mVs−1 after 2000 consecutive CV cycles. In contrast, pure SnO2 exhibited specific capacitance of 648 Fg-1 at scan rate of 5 mVs−1, with 36% retention in capacitance. Results showed that 1 g SnO2 was the optimum concentration for NiO/SnO2 composite to get maximum electrochemical activity. High electrical conductivity and larger surface area arising from synergistic effects between NiO and SnO2 resulted in a great electrochemical response of NiO/1 g SnO2 nanocomposites. The inclusion of the SnO2 improved the electrical impedance spectroscopy results by facilitating the charge transfer.

Facile synthesis of MgCo 2 O 4 hexagonal nanostructure via co‐precipitation approach and its supercapacitive properties

Magnesium cobalt oxide (MgCo2O4) hexagonal nanoplates were prepared via a fast and simple co-precipitation process. The electrochemical properties of MgCo2O4 nanostructures were characterized by various techniques. Furthermore, the MgCo2O4 hexagonal nanoplate material was used for supercapacitors. In three-electrode scheme, MgCo2O4 hexagonal nanoplate electrode demonstrated a good specific capacity of 164 mAh g−1 at 3 A g−1. Furthermore, an aqueous asymmetric supercapacitor (ASC) using MgCo2O4//activated carbon (AC) was also fabricated. The MgCo2O4//AC delivered 39 mAh g−1 of specific capacity at 1 A g−1. It revealed the high energy density of 28.34 W h kg−1 with the power density of 363 W kg−1 with the current density of 0.5 A g−1. The impressive electrochemical performance is mainly associated to high surface area of 55 m2 g−1 resulted from voids/gaps in-between hexagonal nanoplates of MgCo2O4. Also, a toy motor fan, 11 light-emitting diodes (LEDs), and a kitchen timer were functionalized by series linked two ASCs for practical applications.