Plasmonic Ag supported on Ni-doped TiO2 nanospheres for rapid microbial inactivation under visible light

Highlights: • Ag decorated Ni-doped TiO₂ nanospheres are successfully synthesized. • The composites exhibit efficient photocatalytic disinfection efficiencies towards E. coli and F. graminearum. • The mechanisms of enhanced disinfection activity are systematically investigated. -- Abstract: Ni-doped TiO₂ nanospheres decorated with silver plasmonic nanoparticles (Ni-TiO₂/Ag) have been successfully synthesized via sol-gel method and photo-deposition approach. In contrast with pure TiO₂ and Ni-TiO₂, the Ni-TiO₂/Ag composite photocatalysts exhibit markedly enhanced visible-light photocatalytic sterilization efficiencies towards Escherichia coli (E. coli). And more importantly, antifungal experiment reveals that the composite can also disinfect ca. 2.0 log₁₀ cfu·mL⁻¹ Fusarium graminearum (F. graminearum) macroconidia within 3 h. The highly efficient antimicrobial activities are ascribed to the introduction of Ni doping and Ag nanoparticles, which increases the visible light utilization and promotes the separation of electron-hole pairs. The photocatalytic disinfection mechanism is studied with scavengers trapping experiments and electron spin-resonance spectroscopy (ESR), which verifies the key role of • O₂^- and • OH during the microbial inactivation. Our study indicates that the Ni-TiO₂/Ag nanocomposite has great potential for use in pathogenic microorganism remediation.