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In the present work, Magnesium Aluminate (MgAl2O4) nanoparticles and MgAl2O4–graphene nanocomposites with various graphene weight percentages (1, 2, 3, 4, and 5%) were prepared via sol–gel and ultra-sonication methods, respectively. The formation of the spinel phase was confirmed through XRD analysis. Scanning Electron Microscopy was used to study the morphology of the MgAl2O4nanoparticles and their anchoring on the graphene sheets. The FTIR analysis also confirmed the presence of tetrahedral and octahedral bands at 695 and 526 cm−1, respectively. For magnesium aluminate nanoparticles, the bandgap was calculated to be 5.4 eV, which decreases to 4.9 eV with 5% graphene loading on the MgAl2O4–graphene nanocomposites. For methylene blue dye, the degradation efficiency of the 5% MgAl2O4–graphene nanocomposites was also found to be higher (90%) as compared to the pristine MgAl2O4nanoparticles (70%). This increase in efficiency depicts their enhanced photocatalytic activity and strongly suggests that the MgAl2O4–graphene nanocomposites could be a good candidate for industrial wastewater remediation.

A one-step thermo-chemical approach was employed to synthesize ZnFe2O4/rGO nanohybrids with increasing GO concentrations (0, 10, 20, and 30 wt. %). This approach was used to reduce GO while simultaneously synthesizing ZnFe2O4nanoparticles and adhering them to rGO sheets. The nanohybrids were investigated using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and impedance analyzer. The XRD patterns confirmed the formation of a face-centered cubic single phase of ZnFe2O4/rGO nanohybrid and SEM images revealed the decoration of ZnFe2O4/rGO nanoparticles on rGO sheets. The dielectric properties improved as GO loadings increased. At 100 Hz, the dielectric constant and dielectric loss increased to 2.04 × 104and 1.20 × 105for ZnFe2O4/rGO nanohybrid with 30 wt. % of GO when compared to pure ZnFe2O4of 4.23 × 102and 1.92 × 103, respectively. The feasibility of this method implies that this nanohybrid can be used for charge storage devices.

Background: CuFe2O4 nanoparticles possess good electrochemical properties apart from their inadequate electronic conductivity and large volume variation. The resulting performance lag can be modified by the addition of conductive materials to form a composite. Hence, the properties of CuFe2O4/rGO nanohybrid are presented for application as anode material for lithium-ion batteries. Methods: The composites are synthesized through a facile one-step method of thermochemical reaction. The samples are characterized by X-ray diffraction (XRD), Scanning Electron Microscope (SEM), Fourier transform infrared spectroscopy (FTIR), Dielectric behavior and Galvanostatic charge-discharge test. Result & Conclusion: The XRD analysis confirmed the reduction of GO and formation of CuFe2O4/rGO composite, whereas FTIR results showed two major vibrational bands that correspond to spinel structure formation and attachment of rGO to CuFe2O4. The SEM images confirmed tethering of CuFe2O4 nanoparticles with rGO sheets. It was also observed that the formation of the nanohybrid of CuFe2O4 with rGO resulted in expected enhancement of the dielectric properties; dielectric constant and AC conductivity. At 100 Hz frequency, the dielectric constant of the composite with 15 wt. % of GO was 1.2705, which is higher than that of pure CuFe2O4 (3.5704). The parameters such as charge storage capacity and rate capability, which are reminiscent of battery performance were also enhanced with the increase of rGO content in the composite. Hence, a substantial enhancement of battery performance was depicted that projects the composite as a promising candidate for applications in electrode material for lithium-ion batteries.

In the current research work Ba1−xLaxMnyFe12−yO19hexa-ferrite nanoparticles of different compositions were synthesized using chemical co-precipitation technique. The structural properties were explored using X-ray diffractions (XRD), scanning electron microscopy (SEM) and Fourier transmission infrared spectroscopy (FTIR). XRD indexed pattern confirms the formation of M-type hexagonal phase. The crystallite size of synthesized samples ranges from 13 to 34 ± 2 nm. FTIR peaks observe also confirmed the presence of metal–oxygen bond of the desired product. The position of peak at 467 cm−1corresponds to A2u vibration for octahedral Fe(4+)–O and peak position E1ucorresponds to vibration of Fe(3+)O4octahedral bonds. The band v1in range (677–559 cm−1) and v2in frequency range (356–419 cm−1) are associated to A and B sites. Dielectric properties of all compositions were measured with frequency. The dielectric constant, loss and tangent loss decrease from 26 to 9, 25 to 2 and 0.94 to 0.14, respectively with frequency. DC electrical resistivity is increased with dopant concentration increasing from 2.15 × 104to 1.92 × 105 Ω·cm.

One-dimensional CdZnS nanostructures have been synthesized through the sublimation. Effect of high substrate temperature on morphology, structural and optical properties of these nanostructures has been studied. X-Ray diffraction peak intensity, lattice parameters, crystallite size decreased with an increase in substrate temperature. The morphology changed with the increase in the substrate temperature. Raman Spectroscopy confirmed the existence of constituent elements in CdZnS solid solution and an increase of Zn concentration with the rise in substrate temperature. The nanostructures exhibited strong photoluminescence emission in the green light region with a substrate temperature-dependent blue shift of 53 meV in emission energy. The Stoke’s shift energy raised from 45 meV to 302 meV as the substrate temperature increased from 510 °C to 550 °C. The stoichiometric deviancies, crystallite size, and quantum confinement effects resulted into an increase in the optical band gap from 2.4 eV to 2.71 eV. The results showed that CdZnS nanostructures could be potential candidates for nanostructure based optoelectronics and photovoltaic devices.

•A comprehensive overview of both analytical and electrochemical techniques for studying supercapacitors is provided.•Present knowledge on the use, advances, pros, and cons of techniques for the characterization of supercapacitors.•Different characterization techniques are classified according to the information they can provide.•The prospects and challenges associated with supercapacitors in practical applications are also discussed.

•This work explores the importance of sulfides composite for energy storage in supercapacitors.•The synthesized NiCo2S4/WHAC composite exhibit excellent electrochemical performance.•The redox pseudocapacitive behavior of NiCo2S4/WHAC composite storage is revealed.•The capacitive contribution of NiCo2S4/WHAC composite is discussed in detail.•The synthesized material opens the door to promotion and tenure for energy storage.

Title compounds with 0 ≤ x ≤ 1 are synthesized by the reverse microemulsion method using Ni(NO3)2, Fe(NO3)3, and SbCl3as precursors, iso‐octane as oil phase, cetyltrimethylammoniumbromid as surfactant, an BuOH as cosurfactant.