Plant‐Assisted Synthesis of CeO 2 /BiOCl Nanocomposites and Their Antibacterial Activity Against Multidrug‐Resistant Bacteria

ABSTRACT The global escalation of multidrug‐resistant (MDR) bacteria necessitates the development of new antibacterial materials. In this study, CeO 2 /BiOCl nanocomposites are synthesized using garlic ( Allium sativum ) and sunflower petal ( Helianthus annuus ) extracts as natural surfactants and stabilizing agents. Five nanocomposite variants ( p ‐A to P‐E) are prepared and structurally characterized using XRD, SEM, and EDX analyses, confirming the formation of heterojunction BiOCl/CeO 2 phases with improved crystallinity and hierarchical nanoflower morphology under extract‐mediated synthesis. Antibacterial efficacy is assessed against four MDR pathogens Acinetobacter baumannii , Pseudomonas aeruginosa , Escherichia coli , and Staphylococcus aureus at concentrations of 25, 50, and 100 ppm using OD 600 measurements. Results revealed negligible activity at 25 ppm ( p > 0.05), while significant inhibition occurred at 50 ppm, with P‐A and P‐D showing the highest activity against A. baumannii and P. aeruginosa ( p ≤ 0.0001). At 100 ppm, these variants achieved over 60% growth reduction across all tested strains, attributed to synergistic mechanisms involving piezoelectric charge generation and ROS‐mediated oxidative stress. The study demonstrates that plant‐assisted synthesis enhances crystallinity, morphology, and antibacterial performance compared to control samples. These findings establish plant‐assisted synthesized piezoelectric nanocomposites as promising candidates for next‐generation antimicrobial applications in medical and environmental settings.