https://iopscience.iop.org/article/10.1088/2043-6254/aa853a/pdf

Impact of grain size and structural changes on magnetic, dielectric, electrical, impedance and modulus spectroscopic characteristics of CoFe2O4 nanoparticles synthesized by honey mediated sol-gel combustion method

NiO-CNT composite for high performance supercapacitor electrode and oxygen evolution reaction

Photocatalytic removal of Congo red dye using MCM-48/Ni2O3 composite synthesized based on silica gel extracted from rice husk ash; fabrication and application

Covalently bonded polyaniline/graphene composites as high-performance electromagnetic (EM) wave absorption materials Part A Applied science and manufacturing

Effect of nickel oxide nanoparticles as a photocatalyst in dyes degradation and evaluation of effective parameters in their removal from aqueous environments

Correlation between the dielectric and electrochemical properties of TiO2-V2O5 nanocomposite for energy storage application

Ni2O3 nanoparticles of various sizes (∼25.8 to 49.7 nm), obtained by a facile oxidation process using Ni(NO3)2·6H2O, NaOH and sodium hypochlorite as precursor materials at various temperatures (0°, 25°, 50° and 70 °C), are found to remove toxic Cr(VI) from aqueous solution (20 g L−1). The structure, morphology, surface charge and chemical compositions of the synthesized samples were characterized by XRD, TEM, zeta potential and EDX respectively. Adsorption capacity is found to be strongly dependent on the size and surface heterogeneity of the synthesized particles and a plausible mechanism for such significant adsorption efficacy is attributed to the sorbate–sorbent electrostatic interaction and shielding of Cr(VI) ions. The adsorption mechanism fits with the Langmuir isotherm model with maximum 60% Cr(VI) removal capacity (20.768 mg g−1 (calculated) and 20.408 mg g−1 (predicted from isotherms)) corresponding to Ni2O3 nanoparticles, prepared at 70 °C in 3 hours at room temperature. Thermodynamic parameters, obtained from fitting, demonstrate that the adsorption process being endothermic in nature follows a pseudo-second-order kinetic model. The spontaneity of the adsorption process gets reduced with increasing particle size. pH of the solution is observed to have a remarkable effect on the adsorption, giving maximum adsorption at pH = 6.

Synthesis of pure nickel(III) oxide nanoparticles at room temperature for Cr(VI) ion removal

Porous nickel ferrite nanorods having diameter ?200 nm and length ?2.5 to 3.0 ?m were synthesized by microemulsion method followed by calcination at 450 ?C. The morphology and structure of the final as well as intermediate materials, formed during this method, were characterized by x-ray diffraction, field emission scanning electron microscope, high resolution transmission electron microscope and Fourier transform infrared spectroscopy. Positron annihilation spectroscopy was used to identify the structural defects such as vacancies and surface disorder, and to find out the porosity of the synthesized nanorods. M?ssbauer spectroscopy was used to determine the cation distribution and magnetic hyperfine property of the nanorods. Detailed magnetic characterization by measuring magnetization as a function of magnetic field and temperature were examined by physical property measurement system and SQUID magnetometer, respectively. The reduced saturation magnetization (Ms?=?20.3 emu gm?1) and enhanced coercive (Hc?=?37 Oe) field of our synthesized samples was explained on the basis of surface electron effect. Moreover, formation mechanism and effect of precursor materials were also discussed.

http://iopscience.iop.org/article/10.1088/2053-1591/2/4/046102/pdf

NiFe2O4 nanorod: porosity effect on spin canting, quadrupole splitting and hyperfine magnetic properties

Au nanoparticle-decorated aragonite microdumbbells for enhanced antibacterial and anticancer activities

The effect of direct Ag coating on the optical and catalytic properties of NiO flake-like structures has been investigated in detail in this work. Ag nanoparticle decorated NiO flakes were synthesized using a facile two-step process. The phases and crystal structure were examined using an X-ray diffractometer, whereas the morphologies of the synthesized nanostructures were investigated using FESEM and HRTEM. Interfacial interaction of the synthesized heterostructures was examined using Fourier transformation infrared and Raman spectroscopy. Importantly the LO phonon and magnon scattering mode of NiO are significantly affected by the Ag coating. The band gap of NiO is found to be lowered (direct band gap: 3.52 to 2.78 eV and indirect band gap: 2.72 to 0.50 eV) due to the change in valence band energy originating from the charge transfer process between NiO and Ag. A UV emission that depends on the crystal field splitting of the Ni d orbitals is observed to possess a blue shift along with their enhancement of intensity. Variation of the magnon scattering mode also reveals that the enhancement of exchange interaction with NiO nanoflakes causes the blue shift of the UV emission. The nonradiative part corresponding to this UV emission which is parameterized using the Huang-Rhys factor gets enhanced due to the lowering of the electron–phonon interaction. The photocatalytic activity of the synthesized heterostructures was evaluated using the catalytic decomposition of the dye methylene blue in aqueous solution. The results show that the NiO/Ag heterostructures exhibit a much higher degradation rate than virgin NiO flakes that might be from improved separation of the photogenerated electrons and holes. In particular, the pseudo-first-order degradation rate constant of NiO/Ag is found to be 10 times greater than bare NiO.

Swarupananda Bhattacharjee

Papers

Correlation between the dielectric and electrochemical properties of TiO2-V2O5 nanocomposite for energy storage application

Synthesis of pure nickel(III) oxide nanoparticles at room temperature for Cr(VI) ion removal

NiFe2O4 nanorod: porosity effect on spin canting, quadrupole splitting and hyperfine magnetic properties

Au nanoparticle-decorated aragonite microdumbbells for enhanced antibacterial and anticancer activities

NiO/Ag heterostructure: enhanced UV emission intensity, exchange interaction and photocatalytic activity