Antimicrobial activity of metal-substituted cobalt ferrite nanoparticles synthesized by sol–gel technique

Supercapacitors are increasingly used for energy conversion and storage systems in sustainable nanotechnologies. Graphite is a conventional electrode utilized in Li-ion-based batteries, yet its specific capacitance of 372 mA h g−1 is not adequate for supercapacitor applications. Interest in supercapacitors is due to their high-energy capacity, storage for a shorter period and longer lifetime. This review compares the following materials used to fabricate supercapacitors: spinel ferrites, e.g., MFe2O4, MMoO4 and MCo2O4 where M denotes a transition metal ion; perovskite oxides; transition metals sulfides; carbon materials; and conducting polymers. The application window of perovskite can be controlled by cations in sublattice sites. Cations increase the specific capacitance because cations possess large orbital valence electrons which grow the oxygen vacancies. Electrodes made of transition metal sulfides, e.g., ZnCo2S4, display a high specific capacitance of 1269 F g−1, which is four times higher than those of transition metals oxides, e.g., Zn–Co ferrite, of 296 F g−1. This is explained by the low charge-transfer resistance and the high ion diffusion rate of transition metals sulfides. Composites made of magnetic oxides or transition metal sulfides with conducting polymers or carbon materials have the highest capacitance activity and cyclic stability. This is attributed to oxygen and sulfur active sites which foster electrolyte penetration during cycling, and, in turn, create new active sites.

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Advanced materials and technologies for supercapacitors used in energy conversion and storage: a review

https://pureadmin.qub.ac.uk/ws/files/190290035/water_treatment_revised_Review_Accepted_for_publication.pdf

Insight on water remediation application using magnetic nanomaterials and biosorbents

Synthesis and characterization of metals-substituted cobalt ferrite [Mx Co(1-x) Fe2O4; (M = Zn, Cu and Mn; x = 0 and 0.5)] nanoparticles as antimicrobial agents and sensors for Anagrelide determination in biological samples

Ferrimagnetic cobalt ferrite (CoFe2O4) nanoparticles were synthesized by employing co-precipitation method. Product physico-chemical and magnetic properties with respect to cetyl trimethylammonium bromide (CTAB), hexamethylenetetramine (HMT) and polyethylene glycol (PEG-400) surfactants were investigated. XRD pattern and Raman characteristic active modes revealed the cubic cobalt ferrite structure formation. SEM images explored spherical shaped product with different particle size. Identified strong PL emission peaks confirmed the product quality. IR metal oxygen vibration at 615 and 426 cm−1 revealed tetrahedral and octahedral site of cobalt ferrite system. Product electrochemical behavior was found to be size dependent and high specific capacitance was observed using CTAB. Room temperature ferrimagnetic behavior was confirmed through VSM studies. High saturation value as 66 emu/g was found using PEG. Particles with larger crystallite and particle size exhibited improved magnetic behavior.

Ferrimagnetism in cobalt ferrite (CoFe2O4) nanoparticles

Synthesis of ferrofluids based on cobalt ferrite nanoparticles: Influence of reaction time on structural, morphological and magnetic properties

To study the effects of Eu2O3 nanoparticles addition to BSCCO superconducting system, four bulk polycrystalline samples with general formula of Bi1.6Pb0.4Sr2Ca2Cu3Oy+xEu2O3 (where x=0.0, 0.3, 0.5, 1.0 wt%) were prepared by chemical sol–gel method. X-ray diffraction, SEM, and TEM were used for structural characterization of the samples. DC electrical resistivity, critical current, and AC magnetic susceptibility were measured. XRD analysis showed that both (Bi,Pb)-2223 and Bi-2212 phases coexist in the samples having orthorhombic crystal structure. DC electrical resistivity, Jc, and AC magnetic susceptibility measurements reveal that adding Eu nanoparticles to BSCCO improves superconducting properties of this system and enhances its critical current density. The enhancement of the Jc may be caused by improvement of the grain connectivity with Eu nanoparticle additions.

Effect of Eu2O3 Nanoparticles Addition on Structural and Superconducting Properties of BSCCO

In this research barium carbonate nanoparticle with composition BaCO3 (Witherite) was prepared by using the gel-combustion (sol - gel) method. A precursor sol was obtained from barium nitrate. The molar ratio of citrate/nitrate=1.3 (CA/NO-3 =1.3) was used to prepare very fine powders of barium carbonate. The gels resulting from these sols were transformed into powders by an auto-combustion process at ≤400oC. The powders consisted of orthorhombic BaCO3 and one another additional phase. The barium carbonate nano-particles produced by the gel-combustion method were calcined in three different calcination temperatures T = 450 °C, T = 600 °C and T =750 °C. The pure orthorhombic phase was found at 450oC X-Ray diffraction. The effect of calcination temperature was studied in three various temperatures. The crystallite size XRD was estimated from the broadening of XRD peaks, using Scherrer's formula. Transmission electron microscope (TEM) and X-Ray diffraction (XRD) of the samples were used for characterization of the obtain products. The size of particles were produced by this method are between 1nm to 10nm.

Ahmad Amirabadizadeh

Papers

Synthesis of ferrofluids based on cobalt ferrite nanoparticles: Influence of reaction time on structural, morphological and magnetic properties

Effect of Eu2O3 Nanoparticles Addition on Structural and Superconducting Properties of BSCCO

Preparation and Characterization of Barium Carbonate Nanoparticles

Comparative study of magnetic and magnetoimpedance properties of CoFeSiB-based amorphous ribbons of the same geometry with Mo or W additions

Giant magnetoimpedance effect of Co68.15 Fe4.35 Si12.5 B15 amorphous wire in the presence of magnetite ferrofluid