Effect of the molar ratio of (Ni2+ and Fe3+) on the magnetic, optical and antibacterial properties of ternary metal oxide CdO-NiO-Fe2O3 nanocomposites

Optimizing magnetic, dielectric, and antimicrobial performance in chitosan-PEG-Fe2O3@NiO nanomagnetic composites

There is a growing interest in eco-friendly and cost-effective organic-inorganic nanocomposites due to their alignment with the principles of "green" chemistry, as well as their biocompatibility and non-toxicity. This study focused on producing Chitosan-PEG-Fe2O3@NiO nanomagnetic composites to improve the stability, dielectric properties, and antimicrobial effectiveness of these nanocomposite materials. The process involved synthesizing Fe2O3@NiO via sol-gel and polymerizing chitosan-PEG. The nanocomposites were characterized by XRD, TEM, FTIR, optical, dielectric, and VSM. Incorporating Fe2O3@NiO significantly improved stability, and the interaction with Fe2O3 during the sol-gel process facilitated the formation of NiFe2O4 with an increase in the crystallinity within the chitosan-PEG matrix. The study examined optical and dielectric properties, highlighting that the 3 NiO-doped chitosan-PEG-Fe2O3 composites had high electrical conductivity (1.8 ∗ 10-3 S/cm) and a significant dielectric constant (106 at low frequencies). As the ratio of NiO NPs within the chitosan-PEG-Fe2O3 increases, the energy band gap of chitosan-PEG-Fe2O3 films decreases up to 3.7 eV. This decrease is owing to the quantum confinement effect. These composites also demonstrated improved antimicrobial activity against E. coli and S. aureus and higher activity in the presence of nanomagnetic particles. The minimum inhibitory concentrations of CS-PEG-Fe2O3/NiO NPs against (Bacillus cereus, M. luteus, S. aureus and (S. enterica, H. pylori, E. coli) were (22-35 mm) and (21-34 mm), respectively.

Effect of copper oxide (CuO) and vanadium oxide (V2O5) addition on the structural, optical and electrical properties of corundum (α-Al2O3)

In this work, we prepared a pure α-Al2O3, α-Al2O3/CuO (AC) and α-Al2O3/V2O5 (AV) nanocomposite. The sol-gel method was used to prepare pure α-Al2O3, (AC) and (AV) samples at 1200 °C. Structural, electrical, and optical properties of the prepared samples were investigated using the X-ray diffraction (XRD), UV-Visible spectrophotometer, and conductivity meter, respectively. The XRD results confirmed the crystalline nature and the presence of the hexagonal structure of α-Al2O3, the rhombohedra structure of CuAlO2 and the tetragonal structure of V2O5. Moreover, the crystallite size of pure α-Al2O3 was 43.1 nm, while the crystallite size of α-Al2O3 in samples AC and AV nanocompsite was 24.05 nm and 34.84 nm respectively. The optical measurements showed that the band gap α-Al2O3 decreased significantly from 5.28 eV for pure to 3.7 and 3.4 eV to AC and AV respectively. The DC electrical conductivity (σd.c) values were measured for all prepared samples at room temperature. The electrical conductivity was 2.4 × 10-7 and 1.8 × 10-7 (Ω cm)-1 in AC and AV nanocompsite respectively, while ionic conductivity (σion) decreased from 3 × 10-10 in pure α-Al2O3 to 7 × 10-5 and 1 × 10-5 in AC and AV nanocompsite, respectively. The results showed an improvement in the structural, optical, and electrical properties, which may make these materials a candidate for use in many applications, such as photocatalytic, gas sensors, optoelectronics, microelectronics, semiconductor devices, ……etc.