Effect of the Cross-Section Morphology in the Antimicrobial Properties of α-Ag₂WO₄ Rods: An Experimental and Theoretical Study

Abstract

In this work, α-Ag2WO4 particles with different cross-sections were obtained using the co-precipitation method at different synthesis temperatures. The samples were characterized by X-ray diffraction (XRD), field-scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The antimicrobial activity was analyzed using the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) methods against the Escherichia coli and Salmonella spp. gram-negative bacteria. The antimicrobial tests against Escherichia coli and Salmonella spp. indicated that concentrations of 2.5–5 mg/mL and 5 mg/mL completely inhibit its growth, respectively. The antimicrobial activity was analyzed employing band-edge positions for ROS generations and the superficial distribution of Ag+ species that contribute to antimicrobial activity. Quantum-chemical calculations were used at the DFT level to investigate the surface-dependent reactivity of α-Ag2WO4, and we demonstrated how the antimicrobial properties could be tailored by the geometry and electronic structure of the exposed surfaces, providing guidelines for the morphology design.

Keywords

• α-Ag₂WO₄
• cross-section
• antimicrobial activity
• ROS generation
• theoretical study