MAGNETIC PROPERTIES OF NANOCOMPOSITES BASED ON NANOTUBULAR SODIUM TRITITANATE

10.25712/ASTU.1811-1416.2025.01.001

Abstract

Recently, nanostructured Na₂Ti₃O₇ has attracted increasing attention of researchers as a promising material for gas sensors, photocatalysts, orthopedic devices, batteries, supercapacitors, etc. In some cases, the usage of such materials requires magnetic properties, e.g., for separation of nanoparticles from aqueous media or for targeted drug delivery. In this work, a method for preparing composite nanomaterials based on Na₂Ti₃O₇ and Fe₂O₃ (α-phase) multi-walled nanotubes has been developed. The outer diameter of multi-walled nanotubes is 7–10 nm, the inner diameter is 3.5–4 nm, and the distance between walls is 1–2 Å. Na₂Ti₃O₇–Fe₂O₃ nanocomposites were synthesized by a one-step hydrothermal method due to the simultaneous treatment of titanium dioxide and iron trichloride in a concentrated sodium hydroxide solution. Compared to sodium trititanate, Na₂Ti₃O₇–Fe₂O₃ nanocomposites have improved optical activity, especially in the visible region, and a reduced band gap (from 3.29 to 2.85 eV) due to the formation of a heterojunction between two semiconductors. Nanocomposites Na₂Ti₃O₇–Fe₂O₃ exhibit superparamagnetic properties at room temperature, their magnetization increases with increasing Fe₂O₃ phase content, and the coercive force reaches 965 Oe (at 3 K).