Surface-driven photocatalytic and antimicrobial enhancement in Cu-doped Ag2SeO3: Experimental–DFT insights

This study investigates the photocatalytic, antimicrobial, and cytotoxic properties of Cu-doped Ag 2 SeO 3 (ASO) synthesized via a sonochemical route at different Cu contents (0, 2, and 8%). Structural, optical, and morphological analyses reveal that Cu incorporation significantly modifies lattice order, quantum cluster behavior, and particle morphology, leading to distinct surface terminations and charge-carrier dynamics. All samples proved efficient towards the degradation of ciprofloxacin under UV irradiation, especially the sample ASO2C (∼100% in 60 min) with over 50% mineralization. Toxicity and phytotoxicity assessments using Staphylococcus aureus ( S. aureus ) and Lactuca sativa seeds, respectively, indicate that the treated effluent presents reduced biological toxicity, supporting the effectiveness of the photocatalytic process. Additionally, the a ntibacterial assays confirm activity against both Escherichia coli ( E. coli ) and S. aureus , with enhanced inhibition observed for ASO2C, particularly against Gram-negative bacteria. Complimentarily, cytotoxicity tests indicate that the materials are biologically active. Finally, first-principles density functional theory calculations correlate the crystallographic surfaces present in each Wulff morphology with the electronic structure and reactive oxygen species (ROS) formation, revealing that preferential exposure of the (100) surface promotes efficient charge separation and ROS generation. This work represents the first report on metal doping as a strategy towards enhancing the multifunctional properties of ASO, and these combined experimental and theoretical results demonstrate that controlled Cu doping enables surface-driven tuning of ASO properties, resulting in enhanced photocatalytic degradation of pharmaceutical contaminants and improved antimicrobial performance for environmental remediation applications. • Cu doping modulates defect chemistry, enabling facet-dependent charge separation. • Maximum CIP removal for ASO2C via synergistic .•OH and 1 O 2 generation. • Experimental-DFT reveals surface-driven mechanisms governing reactivity. • Dose-dependent toxicity thresholds indicate safe-by-design materials.