Electrospun carbon-TiO₂ composite nanofibers for environmental photoelectrocatalysis

Electrospun nanofiber composites are a promising platform for integrating photocatalytic and electrocatalytic functionalities in environmental remediation technologies. In this study, we report the fabrication, structural characterization, and photo(electro)catalytic evaluation of polyacrylonitrile (PAN)-derived carbon nanofibers embedded with TiO2 nanoparticles (NPs). The NPs are synthesized via two distinct routes: a hydrothermally assisted sol-gel process (SG) and commercial flame-pyrolyzed P25. Aiming for a direct comparison, both fiber types were produced using identical electrospinning conditions and were thermally converted into conductive NP-carbon composites. The fibers containing TiO2 from the SG process exhibit a more homogeneous TiO2 distribution, reduced agglomeration, higher surface area (200 m²/g vs. 78 m²/g), and superior photocatalytic degradation rates of a model organic contaminant, rhodamine B (RhB), outperforming P25-containing fibers even when normalized by surface area. Photoelectrochemical measurements further demonstrate enhanced reaction kinetics under a -0.55 V bias compared to photocatalytic or electrocatalytic conditions alone, confirming the viability of these nanofiber composites for integrated photoelectrocatalysis. These findings highlight the benefits of combining SG-NP synthesis with electrospinning to develop flexible high-performance materials for pollutant degradation applications.