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• Graphitic carbon nitride loaded titania nanofibers as z-scheme photocatalysts. • Synergistic effect by surface plasmon resonance of silver nanoparticles. • Photodegradation of organic dyes and photoreduction of heavy metal ions. • Bactericidal efficiency against E. coli and S. aureus. • Hierarchical multi-functional nanofiber based materials for water remediation. Here, we report synergistic sensitization of electrospun TiO 2 nanofibers (TNFs) by heterojunction formation with exfoliated g-C 3 N 4 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 TiO 2 and g-C 3 N 4 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. [ABSTRACT FROM AUTHOR]

The water pollution becomes a serious concern for the sustainability of ecosystems due to the existence of pharmaceutical products (ceftriaxone (CEF) antibiotic). Even in low concentration of CEF has lethal effects on ecosystem and human health. To remove CEF, TiO 2 is considered as an effective and efficient nanoparticles, however its performance is reduced due to wider energy gap and rapid recombination of charge carriers. In this study, activated carbon based TiO 2 (ACT-X) heterogeneous nanocomposites were synthesized to improve the intrinsic properties of TiO 2 and their adsorption-photocatalytic performance for the removal of CEF. The characterization results revealed that ACT-X composites have slower recombination of charge carriers, lower energy band gap (3.05 eV), and better light absorption under visible region of light. From ACT-X composites, the ACT-4 photocatalyst has achieved highest photocatalytic degradation (99.6%) and COD removal up (99.2%). The results of radical scavengers showed that photocatalytic degradation of CEF is mainly occurred due to superoxide and hydroxyl radicals. Meanwhile, the reusability of ACT-4 up to five cycles shows more than 80% photocatalytic degradation, which make the process more economical. The highest experimental adsorption capacity is achieved up to 844.8 mg g−1 using ACT-4. The favorable and multilayer heterogeneous adsorption is carried out according to the well-fitted data with pseudo-second-order and Freundlich models, respectively. These results indicate that the carbon-based TiO 2 composites can be used as a green, stable, efficient, effective, reusable, renewable, and sustainable photocatalyst to eliminate the pharmaceutical pollutants (antibiotics) via adsorption and photocatalytic degradation processes. [Display omitted] • Activated carbon derived from corncob was successfully coupled with TiO 2 for the formation ACT-X composites. • ACT-4 shows slower recombination of e−/h+, smaller band gap (3.05 eV), and improved visible light absorbance. • ACT-4 achieves more adsorption capacity (844 mg g−1) and photocatalytic degradation (99.6%) for CEF. • Superoxide and hydroxyl radicals are dominant species to degrade CEF. • ACT-4 is more stable, efficient, economical, and reusable for the elimination of CEF. [ABSTRACT FROM AUTHOR]

Metal-oxide based nanostructures, with mixed crystalline phases and high specific surface area, are of great interest due to their excellent performance. Highly porous TiO 2 nanofiber-in-nanotube (NF@NT) structures are developed through triaxial electrospinning, followed by the annealing process. A mixed solution of polyvinyl pyrrolidone, tetrabutyl titanate, and di-isopropyl azodiformate are used in the outer and inner layers of the nanofibers, while paraffin oil is used in the middle layer for separation. Mesoporous TiO 2 NF@NT structure is confirmed through the SEM images. FTIR spectrums reveal the transformation of as-spun polyvinyl pyrrolidone/tetrabutyl titanate/di-isopropyl azodiformate/paraffin oil triaxial nanofiber into TiO 2 NF@NT after the annealing. XRD results show the maximum mixed phases (anatase and rutile) of TiO 2 NF@NT at 450 °C. The transformation of anatase to rutile phase increases with increasing the temperature from 450 °C to 700 °C. BET analysis shows that TiO 2 NF@NT has a higher specific surface area of ~149.67 m2/g compared to the normal TiO 2 nanofiber (~62.00 m2/g). TiO 2 NF@NT performs better photo-degradation of the Sandalfix N.Blue (SNB) under UV-light irradiation than the normal TiO 2 NFs. Moreover, TiO 2 NF@NT, calcined at 450 °C temperature, had the highest SNB degradation (88.1%). These mixed-phase triaxial multifunctional structures could be employed in many applications. [Display omitted] • Highly porous TiO 2 nanofiber-in-nanotube (NF@NT) structures are developed through triaxial electrospinning. • FTIR spectrums reveal the transformation of spun structure into triaxial NF@NT structure. • XRD reveals the maximum mixed phases (anatase and rutile) of TiO 2 NF@NT at 450°C. • TiO 2 NF@NT has a higher specific surface area of ~149.67 m2/g compared to the normal TiO 2 nanofiber (~62.00 m2/g). • TiO 2 NF@NT perform better photo-degradation of SNB (88.04%) under the UV-light irradiation compared to normal nanofiber. [ABSTRACT FROM AUTHOR]