Copper oxide nanoparticles (CuO NPs) and CuO NPs decorated with hematite (Fe₂O₃) nanocomposites (CuO@Fe₂O₃ NC) were biosynthesized by a green method using Portulaca oleracea leaves extract. The NC were characterized using various techniques, including x-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, energy-dispersive x-ray spectroscopy, and UV–vis spectroscopy. The results showed that the synthesized CuO and CuO@Fe₂O₃ NC were crystalline with a monoclinic crystal structure and contained functional groups responsible for catalytic activity. The size of the nanocomposites ranged from 39.5 to 45.9 nm, and they exhibited a variety of agglomerated or aggregated shapes. The CuO@Fe₂O₃ NC showed improved photocatalytic activity for the degradation of antibiotics in water and wastewater and promising antiviral activity against SARS-CoV-2, indicating its potential for use in disinfection applications. The study investigated the impact of irradiation time on the photocatalytic degradation of Amoxicillin and found that increasing the irradiation time led to a higher degradation rate. The band gap energy (E _g) for pure CuO NPs was around 2.4 eV and dropped to 1.6 eV with CuO@Fe₂O₃ NC. In summary, the CuO@Fe₂O₃ NC has the potential to be an efficient photocatalyst and promising antiviral agent for environmental remediation. The CuO@Fe₂O₃ nanocomposites have been found to possess a high degree of efficacy in inactivating SARS-CoV-2 infectivity. The results of the study indicate that the nanocomposites exhibit potent anti-viral properties and hold significant potential for use in mitigating the spread of the virus.

In this study, ZnO@Fe₃O₄ nanocomposite (NC) was synthesized using a green synthesis method with Mentha pulegium leaf extract. Characterization techniques such as UV–vis, FTIR, SEM, TGA, and XRD were employed to confirm the formation of ZnO@Fe₃O₄ NC and thermogravimetric analysis to evaluate the breakdown of NC in the presence of heat. XRD analysis showed a crystallite size of about 25.59 nm and SEM images of ZnO@Fe₃O₄ NC revealed spherical-shaped agglomerated particles. The optical bandgap energy of the ZnO@Fe₃O₄ NC was estimated to be 2.51 eV for direct bandgap and 1.57 eV for allowable indirect bandgap. Photocatalytic activity of the ZnO@Fe₃O₄ NC was evaluated for the degradation of Amoxicillin, Cephalexin, and Metronidazole antibiotics under sunlight irradiation, showing degradation efficiencies of 71%, 69%, and 99%, respectively, suggesting the potential of ZnO@Fe₃O₄ NC for removal of antibiotics from waterways. First-principles theory was employed to establish the adsorption energy (E_ad) of the antibiotic species, including Amoxicillin, Cephalexin, and Metronidazole, on the surface of ZnO@Fe₃O₄ nanocomposite, which was found to be −8.064, −8.791, and −21.385 eV, respectively, indicating strong adsorption. Furthermore, molecular docking studies were conducted to upgrade Fe₃O₄ nanoparticles to ZnO@Fe₃O₄ NC to enhance composite efficiency. Leveraging the FDA-approved use of Fe₃O₄ nanoparticles and their known antiviral activity, our docking experiment demonstrated promising results in the interaction between ZnO@Fe₃O₄ nanocomposite and the spike protein receptor-binding domain of SARS-CoV-2 S Omicron. These findings suggest that ZnO@Fe₃O₄ nanocomposite could potentially inhibit virus attachment to host cell receptors more stably, providing a promising avenue for further exploration in developing effective medications against SARS-CoV-2.

Metal and metal oxide nanoparticles are gaining traction in inorganic catalysis and photocatalysis, driving the development of eco-friendly methods. This study introduces an eco-friendly and cost-effective approach for synthesizing Al₂O₃ nanoparticles (NPs) using extracts derived from the leaves of Calligonum comosum L. The primary objective of this investigation is to assess the photocatalytic efficacy of the synthesized catalyst in addressing organic pollutants. The Al₂O₃ NPs exhibit a spherical morphology with crystalline arrangements, as evidenced by an average crystallite size of 25.1 nm in the XRD analysis. The band gap energy of the Al₂O₃ NPs is determined to be 2.86 eV. In terms of mechanical properties, the Al₂O₃ NPs show significant potential in enhancing both flexural and compressive properties, thereby making them a viable choice for improving the mechanical performance of composites. Notably, the Young’s modulus of the hybrid composite (comprising plant material and Al₂O₃ NPs) exhibits a remarkable increase of 34.4% in flexion and 78.3% in compression compared to the plant material alone. The catalytic performance of the Al₂O₃ NPs is evaluated using methylene blue (MB) as a cationic dye and Rose Bengal (RB) as an anionic dye. Impressively, the Al₂O₃ NPs demonstrate degradation efficiencies of 98.2% for MB and 90.5% for RB. The degradation processes occur under solar light irradiation, with a contact time of 120 m, a maintained pH of 7, and a temperature of 25 °C. This study found that Al₂O₃ nanoparticles are a promising, cost-effective, and environmentally friendly option for water treatment.