TiO₂ nanofibers embedded with g-C₃N₄ nanosheets and decorated with Ag nanoparticles as Z-scheme photocatalysts for environmental remediation

Here, we report synergistic sensitization of electrospun TiO₂ nanofibers (TNFs) by heterojunction formation with exfoliated g-C₃N₄ nanosheets and decorated with Ag nanoparticles (NPs) uniformly over its surface for enhanced photocatalytic activity in simulated solar light. These composite catalysts displayed first-order rate constants of 0.087 min^-1 and 0.031 min^-1 for photodegradation of methylene blue (MB) and photoreduction of Cr(VI) under simulated sunlight which is 75% and 87% higher than the pristine TNFs, respectively, and better than the previously reported results for similar materials. Moreover, 99% of E. coli and 83% S. aureus were inactivated after 60 min of irradiation. The enhanced activities of these prepared ternary composite nanofibers are attributed to the effective Z-scheme heterojunction formation between TiO₂ and g-C₃N₄ due to the preferred band positions which facilitates the charge transfer and inhibit the recombination of charge carriers. Moreover, visible-light harvesting, charge separation and antimicrobial nature of these nanofibers were promoted by the Ag NPs due to the surface plasmon resonance (SPR) effect.