Fe3O4-TiO2 and Fe3O4-SiO2 Core-shell Powders Synthesized from Industrially Processed Magnetite (Fe3O4) Microparticles

Abstract

The interest for core-shells has been increased in the recent years due to their improved and modifiable properties. In this work, Fe 3 O 4 -TiO 2 and Fe 3 O 4 -SiO 2 core-shells were successfully synthesized from an industrially produced magnetite-rich powder with micro-and nanometric particle sizes, superparamagnetic behavior and saturation magnetization of 49 emu/g. The reverse microemulsion method was used to the synthesis of these core-shells. X-ray diffraction, energy dispersive X-ray analysis, electron microscopy (SEM-TEM), and magnetization curves were used to characterize the solids. Core-shells with different morphology and size, coating of crystalline TiO 2 (anatase) or amorphous silica, and superparamagnetic performance at room temperature (300 K) were obtained.

MRI Relaxivity Changes of the Magnetic Nanoparticles Induced by Different Amino Acid Coatings

“…The obtained core diameters (DMAG) are almost identical, indicating that the coating layer does not influence the core (Figure 3 inset). The values were very close and were in the range of values (30 to 80 emu/g) reported in the literature (at 300 K) for synthetic IONPs fine powders [30]. As can be seen from Figure 3, the magnetisation decreases with increased coating layer thickness.…”

“…After recalculating the values per IONPs amount, the saturation magnetization of MNPs, Gly-MNPs, Lys-MNPs, and Trp-MNPs were 62.4, 63.1, 62.7, and 63.3 emu/g IONPs , respectively (Figure 3 inset). The values were very close and were in the range of values (30 to 80 emu/g) reported in the literature (at 300 K) for synthetic IONPs fine powders [30]. (Figure 3 inset).…”

Nanocomposite‐based inorganic‐organocatalyst Cu(II) complex and SiO2‐ and Fe3O4 nanoparticles as low‐cost and efficient catalysts for aniline and 2‐aminopyridine oxidation

“…In addition, the pure Fe 3 O 4 nanoparticles are considered nonporous materials, and their rate of N 2 adsorption is negligible. [ 53 ] The porosity of CuLAn 2 @Fe 3 O 4 and CuLAn 2 @SiO 2 @Fe 3 O 4 nano‐species was evaluated by applying the BET method on the specific surface of the current samples. The BET specific surface area ( S BET ) of CuLAn 2 @SiO 2 @Fe 3 O 4 core‐shell‐shell was 187 m 2 g −1 , which is higher than that of CuLAn 2 @Fe 3 O 4 core‐shell ( S BET ~ 98 m 2 g −1 ).…”

Silica-Coated Magnetic Iron Oxide Nanoparticles Grafted onto Graphene Oxide for Protein Isolation

“…The volume of TEOS precursor is an important factor that affected on the thickness of silica shell of superparamagnetic MNP and the formation of bare SiO 2 NP formation in the solution [46,48]. When TEOS is then added to the mixture, it converts to hydrolyzed TEOS adsorbed onto the superparamagnetic MNP surface, which results in transfer of the superparamagnetic MNPs into the water phase [46].…”