P-doped TiO₂ Nanofibers Decorated with Ag Nanoparticles for Enhanced Photocatalytic Activity under Simulated Solar Light

We report the synthesis of titania nanofibers (TNF) of ∼195 nm mean diameter doped with phosphorus through one-pot electrospinning followed by decoration of Ag nanoparticles (NPs). The Ag NPs of ∼8 nm size on 2 % P-doped TNFs (Ag-PTNFs) showed excellent photocatalytic activity for the reduction of Cr(VI), under simulated solar light, with ∼100 % conversion to Cr(III) in 90 min at pH 3 with a pseudo-first order rate constant of 0.085 min⁻¹ that is 96.5 % higher than TNFs. The Ag-PTNFs also exhibited excellent photodegradation of methylene blue with pseudo-first order rate constant of 0.052 min⁻¹ which is 82.7 % better than TNFs. The enhanced photocatalytic performance of Ag-PTNFs is attributed to the reduced band-gap, increased charge separation and reduced recombination rates. A proposed photocatalytic mechanism based on the synergistic effect of both Ag and P doping is presented which highlights the potential of these composite materials for water remediation.