Fabrication of Yttrium Ferrite Nanoparticles by Solution Combustion Synthesis

The ternary oxide system Y-Fe-O presents fascinating magnetic properties that are sensitive to the crystalline size of particles. There is a major challenge to fabricate these materials in nano-crystalline forms due to particle conglomeration during nucleation and synthesis. In this paper we report the fabrication of nano sized crystalline yttrium ferrite by solution combustion synthesis (SCS) where yttrium and iron nitrates were used as metal precursors with glycine as a fuel. The magnetic properties of the product can be selectively controlled by adjusting the ratio of glycine to metal nitrates. Yttrium ferrite nano-powder was obtained by using three concentration of glycine (3, 6 and 10 wt.%) in the initial exothermic mixture. Increasing glycine content was found to increase the reaction temperature of the system. The structural and magnetic properties of yttrium ferrite before and after annealing at temperature of 1000 °C were investigated by X-ray diffractometry, Differential Scanning Calorimetry (DSC) and cryogenic magnetometry (PPMS, Quantum Design). X-ray diffraction showed that, a broad diffraction peak was found for all samples indicating the amorphous nature of the product. Particle size and product morphology analysis identified that, Nitrate/ glycine combustion caused considerable gas evolution, mainly carbon dioxide, N2 and H2O vapor, which caused the synthesized powders to become friable and loosely agglomerated for glycine concentration from 3 wt.% up to 10 wt.%. The study of the magnetic properties of produced materials in a metastable state was performed by measuring dependencies of Magnetization (M) on temperature, and magnetization on magnetic field strength between 5 K and 300 K. Magnetization measurements on temperature zero-fieldcooled and field-cooled show different patterns when the fraction of glycine is increased. The analysis of zero-field-cooled (ZFC), field-cooled (FC) and magnetization curves of annealed samples confirmed that nanoparticles exhibit superparamagnetic behavior. The increasing concentration of glycine leads to an increased blocking temperature

Updating The Subject Literacy of the Teacher as A Necessity for Improving His Professional Competence

The article shows the need to update the subject literacy of a teacher to improve his professional competence. The concept of subject literacy, its role and place in improving the professional competence of both a teacher and improving the quality of teaching schoolchildren are revealed

Rational extraction of arsenic from copper production waste

Practically and theoretically important are studies aimed at creating new methods for purifying copper electrolyte with the removal of such a dangerous impurity as arsenic in a form suitable for the intended use. Using probabilisticdeterministic planning of the experiment, the course of chemical reactions in manganese- and arsenic-containing systems, the directions of reactions and the stability of their constituent phases were studied. Based on experimental data and thermodynamic analysis, the probable behavior of chemical elements and their compounds, the limits of potential and pH, within which a given compound of an element must be stable, are determined. X-ray diffraction identified the formation of manganese arsenate (Mn3(AsO4)2・4H2O) in deposits formed during the extraction of arsenic from a copper electrolyte with manganese (IV) oxide

Fabrication of Yttrium Ferrite Nanoparticles by Solution Combustion Synthesis

The ternary oxide system Y-Fe-O presents fascinating magnetic properties that are sensitive to the crystalline size of particles. There is a major challenge to fabricate these materials in nano-crystalline forms due to particle conglomeration during nucleation and synthesis. In this paper we report the fabrication of nano sized crystalline yttrium ferrite by solution combustion synthesis (SCS) where yttrium and iron nitrates were used as metal precursors with glycine as a fuel. The magnetic properties of the product can be selectively controlled by adjusting the ratio of glycine to metal nitrates. Yttrium ferrite nano-powder was obtained by using three concentration of glycine (3, 6 and 10 wt.%) in the initial exothermic mixture. Increasing glycine content was found to increase the reaction temperature of the system. The structural and magnetic properties of yttrium ferrite before and after annealing at temperature of 1000 °C were investigated by X-ray diffractometry, Differential Scanning Calorimetry (DSC) and cryogenic magnetometry (PPMS, Quantum Design). X-ray diffraction showed that, a broad diffraction peak was found for all samples indicating the amorphous nature of the product. Particle size and product morphology analysis identified that, Nitrate/glycine combustion caused considerable gas evolution, mainly carbon dioxide, N2 and H2O vapor, which caused the synthesized powders to become friable and loosely agglomerated for glycine concentration from 3 wt.% up to 10 wt.%. The study of the magnetic properties of produced materials in a metastable state was performed by measuring dependencies of Magnetization (M) on temperature, and magnetization on magnetic field strength between 5 K and 300 K. Magnetization measurements on temperature zero-fieldcooled and field-cooled show different patterns when the fraction of glycine is increased. The analysis of zero-field-cooled (ZFC), field-cooled (FC) and magnetization curves of annealed samples confirmed that nanoparticles exhibit superparamagnetic behavior. The increasing concentration of glycine leads to an increased blocking temperature

Palladium catalysts supported on carbonized porous silicon for H2/O2 recombination

The article presents new research on the use of catalysts for H2/O2 recombination. The study emphasizes the importance of ensuring safe production, storage, and utilization of green hydrogen by recombining gas leaks. We suggest the utilization of innovative palladium catalysts for low-temperature hydrogen oxidation. These catalysts leverage molecular oxygen from the air to efficiently recombine small amounts of leaked hydrogen, resulting in the production of water. Recombination catalysts with a small amount of dispersed palladium metal on an inert support are the most efficient for production to prevent the risks of hydrogen explosion and fire. This study is focused on the development of laboratory prototypes for the H2/O2 recombination catalysts. We identified a potential catalytic system through monitoring of current literature to propose efficient hydrogen recombination catalysts. We present an optimized method for coating the surface of porous silicon nanoparticles with carbon layers, and introduce a technique for the production of supported palladium recombination catalysts. The proposed catalysts efficiently facilitate the recombination of hydrogen in lean air-hydrogen gas mixtures, offering a cost-effective alternative to more expensive commercial catalysts. Furthermore, they exhibit remarkable efficiency at both room and elevated temperatures. The final remarks underscore the necessity of creating new Pd catalysts to guarantee the secure storage and usage of hydrogen

Solution-combustion synthesis and magnetodielectric properties of nanostructured rare earth ferrites

Rare earth ferrites exhibit remarkable magnetodielectric properties that are sensitive to the crystallite size. There is a major challenge to produce these materials in nanoscale due to particles conglomeration during the ferrite nucleation and synthesis. In this paper we report the fabrication of nanostructured particles of rare earth ferrites in the Me-Fe-O system (Me = Y, La, Ce, and Sm) by Solution-Combustion Synthesis (SCS). The yttrium, lanthanum, cerium, samarium and iron nitrates were used as metal precursors and glycine as a fuel. Thermodynamic calculations of Y(NO3)3-2Fe(NO3)3−nC2H5NO2 systems producing Y3Fe5O12 predicted an adiabatic temperature of 2250 K with generating carbon dioxide, nitrogen and water vapor. The considerable gas evolution helps to produce the synthesized powders friable and loosely agglomerated. Adjusting the glycine/metal nitrates ratio can selectively control the crystallite size and magnetodielectric properties of the ferrites. Increasing the glycine content increased the reaction temperature during the SCS and consequently the particle size. Magnetization of zero-field-cooled (ZFC) and field-cooled (FC) ferrites in the temperature range of 1.9–300 K showed different patterns when the fraction of glycine was increased. Analysis of ZFC and FC magnetization curves of annealed samples confirmed that nanoparticles exhibit superparamagnetic behavior. The increasing concentration of glycine leads to escalation of blocking temperature. Reduction of dielectric permittivity (ɛr) toward frequency indicates the relaxation processes in the composites, and the values of ɛr are shifted upward along the operating temperature

Updating The Subject Literacy of the Teacher as A Necessity for Improving His Professional Competence

The article shows the need to update the subject literacy of a teacher to improve his professional competence. The concept of subject literacy, its role and place in improving the professional competence of both a teacher and improving the quality of teaching schoolchildren are revealed.El artículo muestra la necesidad de actualizar la asignatura de alfabetización de un docente para mejorar su competencia profesional. Se revela el concepto de alfabetización en materias, su papel y lugar en la mejora de la competencia profesional tanto de un maestro como en la mejora de la calidad de la enseñanza a los escolares

Rational extraction of arsenic from copper production waste

Practically and theoretically important are studies aimed at creating new methods for purifying copper electrolyte with the removal of such a dangerous impurity as arsenic in a form suitable for the intended use. Using probabilisticdeterministic planning of the experiment, the course of chemical reactions in manganese- and arsenic-containing systems, the directions of reactions and the stability of their constituent phases were studied. Based on experimental data and thermodynamic analysis, the probable behavior of chemical elements and their compounds, the limits of potential and pH, within which a given compound of an element must be stable, are determined. X-ray diffraction identified the formation of manganese arsenate (Mn3(AsO4)2・4H2O) in deposits formed during the extraction of arsenic from a copper electrolyte with manganese (IV) oxide