Interfacial Charge Engineering in RGO/TiO2-PAN Photocatalytic Fibers for Efficient Dye Degradation

Abstract Interfacial charge engineering is an effective strategy to overcome rapid electron−hole recombination and limited light utilization in conventional photocatalysts. Herein, reduced graphene oxide (RGO)/TiO2 hybrid photocatalysts were constructed and integrated into polyacrylonitrile (PAN) fibers via wet spinning to fabricate porous RGO/TiO2-PAN photocatalytic fibers. The incorporation of RGO induced a hierarchical porous structure with an increased surface area (32.43 m2 g−1) and uniform dispersion of TiO2 nanoparticles. Benefiting from strong π−π interactions and abundant adsorption sites, the fibers achieved 96.5% removal of methylene blue (MB) under dark conditions. Under irradiation, the fibers exhibited superior photocatalytic performance, enabling complete degradation of 50 mg L−1 MB within 2 h, with a rate constant 2.27 times higher than that of TiO2 fibers. The enhanced performance arises from the synergistic coupling of interfacial charge transfer and hierarchical porous architecture, which facilitates rapid electron migration, suppresses charge recombination, and promotes pollutant adsorption. This is evidenced by reduced photoluminescence, enhanced photocurrent response, and a narrowed band gap (3.13 to 2.87 eV). Mechanistic studies indicate that •OH radicals dominate the degradation process, assisted by h+ and •O2− species. The fibers also exhibit excellent stability and reusability, maintaining 96% efficiency after four cycles, and demonstrate broad applicability toward various dyes, achieving rapid and complete removal of malachite green (MG), neutral red (NR), and their mixed dye systems within 70 min. Overall, this work provides a scalable strategy for integrating interfacial charge engineering with fibrous architectures toward efficient and sustainable photocatalytic wastewater treatment.