Chabazite-supported ZnO and CeO2 nanoparticles with structural stability and enhanced antibacterial action

Chabazite (CHA) was synthesized by the hydrothermal fusion method, and zinc oxide/cerium oxide nanoparticles (ZnO/CeO2-NPs) supported on CHA were subsequently synthesized by the sol-gel method. The incorporation of the ZnO/CeO2-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/CeO2 spherical NPs with average particle sizes between 8 and 9 nm, and EDX confirmed the homogeneous incorporation of ZnO/CeO2-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/CeO2-NPs loading, associated with a surface redistribution of the ZnO/CeO2-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 Zn2+. These multifunctional materials are promising for biomedical applications.