Titanium dioxide (TiO₂) is widely used in photocatalysis applications for wastewater treatment. Investigations demonstrated that titanium dioxide structure strongly contributes to increase micropollutant degradation efficiency. Indeed, pollutant degradation rates are enhanced when using photocatalysts with highly ordered structures and high specific surface area, such as TiO₂ nanotubes (NTs) synthesized by atomic layer deposition (ALD). Here, TiO₂ NTs, fabricated by ALD followed by nitrogen doping via thermal treatment, were compared with TiO₂ nanofibers (NFs), prepared by electrospinning. Their morphology and structure were investigated by scanning and transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. Photoluminescence measurements showed that TiO₂ NT photoluminescence intensity was lower than that of TiO₂ NFs, due to lower electron-hole pair recombination, and consequently their degradation efficiency was higher. As the surface to volume ratio was higher in TiO₂ NTs than NFs, the rate of non-radiative surface recombination also was higher in TiO₂ NTs. Comparison of their performance for photocatalytic degradation of acetaminophen showed higher degradation activity with TiO₂ NTs than TiO₂ NFs. TiO₂ NT doping with nitrogen (N-TiO₂ NTs) further enhanced their photocatalytic activity that was 5 times higher than that of TiO₂ NFs (degradation rates: 0.05 and 0.01 mg.L⁻¹.min⁻¹, respectively). The N-TiO₂ NT photocatalyst was stable after four cycles of acetaminophen degradation. Acute toxicity assays confirmed the release of harmful by-products during the first hours of acetaminophen degradation, but toxicity strongly decreased after 5 h.