Multifunctional prospects of PMMA/Fe₂O₃@NiO nanocomposite membranes: advanced optical, dielectric, and photocatalytic properties for electronic optoelectronic devices, and environmental applications

A novel polymeric nanocomposite (PNC) membrane composed of PMMA and Fe₂O₃@NiO nanocomposite was successfully synthesized using the solution-casting method, incorporating different weight percentages of Fe₂O₃@NiO core-shell nanoparticles. Fe₂O₃@NiO nanostructures were fabricated using a sol–gel method and characterized by XRD, FTIR, FE-SEM, EDX, and UV-Vis diffuse reflectance spectroscopy (DRS). Structural analysis confirmed the cubic structure of Fe2O3@NiO NCs and effective interactions between polymer and nanocomposite fillers, while FTIR results indicated modifications in chemical bonding. From FE-SEM analysis, it is evident that particles exhibit a spherical shape with an average grain size of 45 nm. Optical studies demonstrated a significant decline in the indirect band gap (E_gid), which drops from 4.52 eV to 3.4 eV, while direct band gap (E_gd) declines from 4.96 eV to 4.53 eV as the NCs ratio increases. Additionally, the optical limiting properties were studied using 650 nm and 532 nm laser sources, demonstrating superior laser shielding performance with 99% and 96% attenuation, respectively. As incident frequency increases, both dielectric constant and dielectric loss decrease exponentially; however, as Fe₂O₃@NiO NCs content increases, their AC electrical conductivity improves. The photocatalytic efficacy of a sustainable solution for water contamination and membrane degradation of Brilliant Green (BG) dye was also evaluated, achieving an impressive 98.27% degradation in just 5 min, with a high kinetic rate constant of 0.7315 min⁻¹, attributed to interaction with hydroxyl radicals (^•OH).