Synthesis and Properties of Ferrite-Based Nanoparticles

The work is dedicated to the study of the structural and optical characteristics, as well as the phase transformations, of ferrite nanoparticles of CeO₂-Fe₂O₃. To characterize the results obtained, the methods of scanning and transmission microscopy, X-ray diffraction (XRD) spectroscopy, and Mössbauer spectroscopy were applied. It was found that the initial nanoparticles are polycrystalline structures based on cerium oxide with the presence of X-ray amorphous inclusions in the structure, which are characteristic of iron oxide. The study determined the dynamics of phase and structural transformations, as well as the appearance of a magnetic texture depending on the annealing temperature. According to the Mossbauer spectroscopy data, it has been established that a rise in the annealing temperature gives rise to an ordering of the magnetic properties and a decrease in the concentration of cationic and vacancy defects in the structure. During the life test of synthesized nanoparticles as cathode materials for lithium-ion batteries, the dependences of the cathode lifetime on the phase composition of nanoparticles were established. It is established that the appearance of a magnetic component in the structure result in a growth in the resource lifetime and the number of operating cycles. The results show the prospects of using these nanoparticles as the basis for lithium-ion batteries, and the simplicity of synthesis and the ability to control phase transformations opens up the possibility of scalable production of these nanoparticles for cathode materials.

Deposition of Gold Nanostructures into Porous SiO2∕Si Templates from the Electrolyte Based on Au(I) Sulfite Complex

Gold nanostructures were fabricated in porous SiO2/Si ion-track templates by the wet chemical deposition from a solution of Au(I) sulfite complex. Their morphological features were analyzed, and features of the deposition processes were determined. A mechanism describing the selective formation of gold nanostructures in the pores of SiO2 was proposed. The present approach allows us to control shape and size of Au nanostructures those which can be used as plasmonic active surfaces for SERS detecting of small amounts of biological and chemical substances.