Construction of antimicrobial CeO2/Fe2O3 nanomaterials with enzyme-like activity and study of their mechanisms

This study employed rare earth element, Ce, and elemental Fe to prepare antimicrobial nanocomposites with enzyme-like activity. The materials were characterized by SEM, EDS, and XRD, as well as antimicrobial and drug resistance properties were tested. XPS analysis revealed a change in the valence state of Ce 3d in CeO2/Fe2O3 on addition of Fe. Furthermore, UV–vis spectral results showed that the band gap of the composite material decreased after composite formation. The creation of a heterogeneous structure was a significant factor responsible for enhancing the antimicrobial performance. The study analyzed the peroxidase (POD) activity of the materials using UV–vis spectroscopy. Results showed that the enzyme activity of the composites was significantly enhanced, compared to the individual materials. This enhancement combined with H2O2 to induce the production of ROS, resulted in a significant increase in the antimicrobial effect. The antimicrobial rate of the composite material exceeded 90 % at 250 µg/mL concentration. The antibacterial mechanism revealed that it primarily operated through synergistic effects of ROS, ionic dissolution, and damage by adsorption. It also had an apparent inhibitory effect on bacterial micro-organisms in water, which has wider application prospects.