Co-doped magnetic N-TiO_2-x/rGO heterojunction@cellulose nanofibrous flakelet for enhanced photocatalytic oxidation and facile separation: Efficient charge separation and self-floatability

Visible-light-absorbing N-TiO_2-x/rGO@cellulose nanohybrid photocatalyst with magnetism and self-floatability was fabricated via a facile in-situ nanocomposite strategy. The co-doping levels of nitrogen and oxygen vacancies formed bandgap states highly broadening the visible-light harvesting. The N-TiO_2-x/rGO heterojunction remarkably enhanced the interfacial charge separation for excellent photocatalytic activity. Bisphenol A (10 mg·L⁻¹) was photodegraded practically (96.2%) by this nanohybrid within 60 min through the synergistic oxidation via persulfate activation. Radical trapping experiments and EPR measurement revealed that the photo-induced superoxide radical (·O₂^–) and hydroxyl radical (·OH) were the predominant reactive oxidizing species. The nanohybrids were stably floating on aqueous solutions for an unprecedented long period of time (up to 5 months) and can be reused without difficult separation or photocatalytic attenuation. Contact angle measurement and thermodynamic model were combined to reveal the floatable nature. This work is therefore of interest for inexpensive and scalable manufacturing of multi-featured visible-light photocatalyst towards environmental remediation applications.