Effect of Fe doping on the photocatalytic activity of TiO₂ hollow fibers under LED light irradiation

Abstract

Fe-doped TiO2 hollow fibers (Fe-THF) were prepared using a template replication method with kapok as the template. The Fe concentration was varied by adjusting the amount of iron (III) nitrate from 0 to 5 mol%. The effect of Fe doping on morphology, crystal structure, bandgap energy, and photocatalytic activity was investigated and discussed. Based on the characterization results, it was found that all samples possessed a hollow structure with anatase as the main crystalline phase. The rutile phase began to be observed with high-level doping. Bandgap energy decreased significantly from 3.02 to 2.12 eV as the Fe concentration increased, owing to the formation of intermediate energy level. The photocatalytic activity was probed using the degradation of methylene blue under light-emitting diode (LED) irradiation. We found that the photocatalytic activity of Fe-THF was inferior to undoped THF and decreased with increasing Fe concentration. This result indicated that Fe dopant could act as the recombination centers in the lattice system, thus inhibiting the photocatalytic activity of THF.