Designing potent plasmonic Ag/TiO₂ nanohetero-phase junction for visible light driven photo-catalysis and...

In this study, we have reported the impact of well-grown Ag nanoparticles on TiO₂ nanofiber mat, focusing the efficiency in anti-bacterial properties with ROS generation. Herein, the nanoheterostructure sample was achieved using electrospinning technique, followed by a solvothermal approach. The core focus was based on the effect of growth of Ag nanoparticles by varying the solvothermal time as well as the molar weight of Ag precursor against both the anti-bacterial property with gram-negative (e.g. E. coli) and another gram-positive (e.g. E. faecalis) bacterium. Prior to the detailed anti-bacterial test, the morphological analysis and the heterojunction formation was thoroughly investigated which showed the clear growth of Ag nanoparticles upon altering the experimental parameters via HRTEM analysis. The investigation showed that superior antibacterial activity was exhibited for the higher Ag loaded heterojunction samples whereas there showed no effect in the absence of Ag nanoparticles for TiO₂ nanofibers. This is basically due to the presence of higher superoxide radicals in the nanoheterojunction materials, which is proved by a systematic study using the NBT degradation test under dark and visible light environment. Moreover, this phenomenon can be elucidated by the surface plasmon resonance effect in Ag nanoparticles, which when illuminated under visible light generates electrons and is transferred to the conduction band of TiO₂. This transfer promotes the generation of reactive oxygen species (ROS), resulting in the exceptional antibacterial properties observed in AgT-10 ˃ AgT-5 ˃ AgT-2.5 ˃ TiO₂NF.