The contamination of both soil and water by nitrobenzene (NB) is a problem that has been studied, where several reactive agents have been developed for the degradation of this compound as well as different methods. Nanoparticles with semiconductive properties have been studied for organic compounds photodegradation due to their assistance in optimizing the degradation processes. Two of the most promising photocatalysts are ZnO and TiO₂ because of their optimal results. In the present work the performance of the zinc peroxide (ZnO₂) nanoparticles was evaluated. ZnO₂ nanoparticles were synthesized from zinc acetate and hydrogen peroxide using the Sol-Gel method under ultrasound assistance. The characterization was carried out by UV–Vis spectroscopy, infrared Fourier transform total reflectance (ATR-FT-IR) spectroscopy, Raman spectroscopy, X-ray diffraction (XRD), Zeta potential, dynamic light scattering (DLS), field emission scanning electron microscopy (FE-SEM), and Energy Dispersive X-ray spectroscopy (EDX). The experiments for the degradation of NB were carried out in a photoreactor with UV lamps of 254 nm at 25 °C, using a solution of nitrobenzene with the nanoparticles. The best conditions for NB photodegradation were 30 ppm (ZnO₂) and 15 ppm (NB) at pH 2, reaching up to 90% degradation in 2 h. The intermediates formed during the photodegradation of NB were identified by gas chromatography mass spectrometry.

Chabazite (CHA) was synthesized by the hydrothermal fusion method, and zinc oxide/cerium oxide nanoparticles (ZnO/CeO ₂ -NPs) supported on CHA were subsequently synthesized by the sol-gel method. The incorporation of the ZnO/CeO ₂ -NPs (up to 25 wt.%) on structural, morphological and optical properties has been studied, and the applications of the materials in antibacterial studies have also been evaluated. XRD analysis confirmed the preservation of the zeolitic structure with progressive reduction of relative crystallinity. FTIR results showed that the CHA framework bands were preserved, although with evidence of surface interaction with the metallic phases. SEM and TEM images revealed a progressive coverage of the support with well-dispersed ZnO/CeO ₂ spherical NPs with average particle sizes between 8 and 9 nm, and EDX confirmed the homogeneous incorporation of ZnO/CeO ₂ -NPs. UV-vis showed a shift of the absorption edge towards the visible range, attributed to Ce doping and modification of the electronic structure. BET analysis indicated an initial decrease in surface area due to pore blocking, followed by a recovery in samples with higher ZnO/CeO ₂ -NPs loading, associated with a surface redistribution of the ZnO/CeO ₂ -NPs and increased textural accessibility. Antimicrobial assays against Pseudomonas aeruginosa (P. aeruginosa) , Enterococcus faecalis (E. faecalis) and Staphylococcus aureus (S. aureus) showed concentration-dependent inhibition, being the gram-negative strains more sensitive. The synergistic antimicrobial effect was related to adsorption, generation of reactive oxidative species (ROS) and release of Zn ²⁺ . These multifunctional materials are promising for biomedical applications.