Tailoring Ag-Co co-doped BaTiO3/graphene oxide nanocomposite as a solar-light-driven multifunctional photocatalyst for wastewater remediation and antibacterial applications

Addressing the pressing need for integrated wastewater remediation, photocatalysts capable of simultaneously removing organic contaminants and inactivating pathogenic microorganisms have become a major research focus. In this work, a multifunctional Ag-Co co-doped BaTiO 3 /GO nanocomposite was synthesized via a facile co-precipitation and calcination route. Dual-site incorporation of Ag and Co within the BaTiO 3 perovskite lattice, combined with graphene oxide integration, induced synergistic electronic modulation and enhanced interfacial charge-transfer. This engineered structure resulted in bandgap narrowing, the introduction of intra-bandgap states, improved electron-hole separation, and reduced charge-transfer resistance, accompanied by the photosensitizing and electron-reservoir roles of GO, as confirmed by structural, optical, and electrochemical analyses. Photocatalytic tests under simulated solar light revealed complete methylene blue (MB) degradation within 180 min with a pseudo-first-order rate constant of 0.0299 min –1 . Radical scavenging experiments identified hydroxyl and superoxide radicals as the dominant oxidative species. Furthermore, the nanocomposite maintained high structural stability and photocatalytic efficiency over four consecutive cycles. Antibacterial assays demonstrated astonishing bactericidal performance, with >99% inactivation of Staphylococcus aureus ( S. aureus ) in 6 h and >99.9% elimination of Escherichia coli ( E. coli ) within 3 h. These findings establish Ag-Co co-doped BaTiO 3 /GO nanocomposite as a robust, recyclable, and efficient multifunctional photocatalyst for solar-driven sustainable wastewater remediation and microbial disinfection, turning it into a promising material for self-cleaning purposes.